---

PHARMACEUTICS — Long Answers (15 Marks Each)

---

UNIT I: Introduction to Dosage Forms

---

Q1. Define Dosage Form and Give a Detailed Classification Based on Physical State & Route of Administration. Explain the Importance of Dosage Form in Drug Delivery with Suitable Examples.

---

Definition of Dosage Form

---

Classification of Dosage Forms

• Immediate Release (IR): Drug releases rapidly — conventional tablets/capsules
• Modified Release (MR):
  • Sustained Release (SR): Prolonged drug release (e.g., metformin SR)
  • Extended Release (XR/ER): Slower release over extended period
  • Delayed Release (DR): Enteric-coated tablets (release in intestine, e.g., omeprazole EC)
  • Controlled Release (CR): Near zero-order release kinetics

---

Importance of Dosage Form in Drug Delivery

1. Accurate Dosing: Tablets and capsules contain precise, pre-measured doses, reducing dosing errors. E.g., 500 mg paracetamol tablet.
2. Drug Stability: Dosage forms protect drugs from degradation by moisture, heat, light, and oxidation. E.g., enteric coating protects aspirin from gastric acid.
3. Improved Bioavailability: Form affects absorption rate and extent. E.g., sublingual nitroglycerin bypasses first-pass metabolism, providing rapid onset in angina.
4. Patient Compliance: Palatability, ease of swallowing, and convenient dosing schedules improve compliance. E.g., chewable tablets for children, once-daily SR tablets for adults.
5. Site-Specific Delivery: Topical dosage forms deliver drug to the site of action, minimizing systemic side effects. E.g., betamethasone cream for skin inflammation.
6. Controlled Release: SR/CR formulations maintain steady plasma levels, avoiding peaks (toxicity) and troughs (therapeutic failure). E.g., nifedipine GITS for hypertension.
7. Protection of Gastric Mucosa: Enteric-coated forms (e.g., diclofenac EC) bypass the stomach to reduce GI irritation.
8. Route-Specific Benefits: Inhalation dosage forms (MDI) deliver bronchodilators directly to the lung, allowing very small doses with minimal systemic effects.
9. Handling of Incompatible Drugs: Fixed-dose combinations are formulated as bi-layer tablets or separate compartments to prevent drug-drug physical incompatibility.
10. Masking Unpleasant Taste/Odor: Sugar coating, flavoring in syrups, and capsule shells mask bitter drugs (e.g., chloroquine).

---

Q2. Define Prescription and Discuss All Its Parts in Detail. Also Explain the Role of a Pharmacist in Reading and Interpreting Prescriptions.

---

Definition of Prescription

---

Parts of a Prescription

• The symbol "Rx" (from Latin Recipe = "take thou")
• Date of the prescription
• Patient's name, age, sex, and address

• The name of the drug — generic or brand name
• Strength/concentration of the drug (e.g., 500 mg, 0.1%)
• Dosage form (tablet, capsule, syrup, ointment, etc.)
• Quantity to be dispensed (e.g., #30 tablets, 100 mL)

• Instructions to the pharmacist about:
  • How to prepare the medication (for compounding prescriptions)
  • Number of units to be dispensed
  • Any special dispensing instructions (e.g., "dispense in amber bottle")

• The directions to the patient — written in abbreviated Latin or English
• E.g., "1 tab TID × 5 days" = one tablet three times daily for five days
• Route of administration, timing with food, special storage instructions

• Name, qualifications, and registration number of the prescriber
• Clinic/hospital address and contact number
• Date and signature of the prescriber

• Whether the prescription may be refilled and how many times
• Particularly important for controlled/scheduled drugs

• "Take with plenty of water"
• "Avoid alcohol"
• "Shake well before use"
• "Keep refrigerated"

---

Common Latin Prescription Abbreviations

---

Role of the Pharmacist in Reading and Interpreting Prescriptions

• Check that the prescription is genuine, dated, and signed by a registered prescriber
• Verify prescriber's registration number

• Confirm the patient's name, age, and address to prevent dispensing to the wrong person
• Age is especially important in pediatric and geriatric patients (dose adjustments)

• Decipher handwriting accurately — illegible prescriptions must be clarified with the prescriber before dispensing
• Never guess an unclear drug name or dose

• Check that the prescribed drug, dose, and dosage form are appropriate for the patient's condition, age, weight, and renal/hepatic function

• Review the patient's current medication profile for clinically significant drug-drug interactions (e.g., warfarin + aspirin → increased bleeding risk)

• Confirm that the prescribed dose is within the safe therapeutic range
• For children, verify dose by weight/age (e.g., paracetamol 10–15 mg/kg/dose)

• Screen for documented drug allergies or hypersensitivity reactions before dispensing

• Explain how to take the medication (route, frequency, duration)
• Advise on storage (refrigeration, light protection)
• Warn about common side effects and what to do if they occur
• Emphasize adherence and completion of course (especially antibiotics)

• Maintain records of dispensed prescriptions in accordance with legal requirements
• For controlled/scheduled substances, detailed records are mandatory

• Ensure compliance with the Drugs & Cosmetics Act and Schedule H/H1/X regulations
• Refuse to dispense prescriptions that appear forged or are out of scope

---

Q3. What is Posology? Discuss in Detail the Various Factors Affecting Drug Dosage, Including Age, Weight, Sex, Pathological Conditions, and Tolerance.

---

Definition of Posology

---

Factors Affecting Drug Dosage

• Neonates (0–1 month):
  • Immature liver enzyme systems (CYP450)
  • Reduced renal function
  • Higher body water content → larger volume of distribution for water-soluble drugs
  • Example: Chloramphenicol → "Grey Baby Syndrome" due to inability to conjugate
• Infants & Children:
  • Dose calculated by body weight (mg/kg) or body surface area (mg/m²)
  • BSA method is more accurate (accounts for metabolic rate)
• Elderly (> 65 years):
  • Reduced GFR → accumulation of renally cleared drugs (e.g., digoxin, aminoglycosides)
  • Reduced hepatic mass and blood flow → prolonged half-life of many drugs
  • Decreased albumin → more free drug (e.g., warfarin, phenytoin)
  • Increased sensitivity of CNS receptors → lower doses of sedatives needed
  • Polypharmacy risk → increased drug interactions

• Young's Rule (for children 1–12 years): $$\text{Child's dose} = \frac{\text{Age (years)}}{\text{Age} + 12} \times \text{Adult dose}$$
• Dilling's Rule: $$\text{Child's dose} = \frac{\text{Age (years)}}{20} \times \text{Adult dose}$$
• Clark's Rule (based on weight): $$\text{Child's dose} = \frac{\text{Weight (lb)}}{150} \times \text{Adult dose}$$ (Or weight in kg ÷ 68 × adult dose)
• Fried's Rule (for infants < 1 year): $$\text{Infant's dose} = \frac{\text{Age (months)}}{150} \times \text{Adult dose}$$
• BSA Method (most accurate): $$\text{Child's dose} = \frac{\text{Child's BSA (m}^2)}{1.73 \text{ m}^2} \times \text{Adult dose}$$

---

• Obese patients may require higher absolute doses of lipophilic drugs (greater Vd)
• For hydrophilic drugs, lean body weight is more relevant
• Standard doses assume 70 kg adult body weight

• Women generally have higher body fat percentage → greater Vd for lipophilic drugs
• Lower plasma volume in women → higher peak concentrations of water-soluble drugs
• Hormonal changes (menstrual cycle, pregnancy, menopause) affect drug metabolism
• Pregnancy: Avoid teratogenic drugs (Category X); physiological changes (increased GFR, altered protein binding) alter pharmacokinetics

• IV route bypasses absorption → 100% bioavailability → lower dose needed
• Oral route subject to first-pass metabolism → higher dose needed (e.g., propranolol oral dose >> IV dose)

• Renal impairment: Reduced excretion → dose reduction or increased interval for renally cleared drugs (digoxin, aminoglycosides, metformin, lithium)
• Hepatic impairment: Reduced metabolism → dose reduction for hepatically metabolized drugs (morphine, benzodiazepines, warfarin)
• Cardiac failure: Reduced hepatic blood flow → reduced first-pass metabolism; reduced renal perfusion → reduced drug clearance
• Thyroid disorders: Hyperthyroidism increases drug metabolism; hypothyroidism decreases it
• Hypoalbuminemia: Increased free fraction of highly protein-bound drugs (warfarin, phenytoin) → toxicity at normal doses

• Pharmacological tolerance: Reduced response to a drug with repeated use → dose escalation required (e.g., morphine, alcohol, benzodiazepines)
• Cross-tolerance: Tolerance to one drug conferring tolerance to related drugs (e.g., tolerance to one opioid = tolerance to others)
• Tachyphylaxis: Rapid development of tolerance after a few doses (e.g., ephedrine, nitrates)

• CYP2D6 poor metabolizers: codeine fails to convert to morphine (no effect)
• Slow acetylators: accumulate isoniazid → peripheral neuropathy at standard doses
• G6PD deficiency: primaquine, dapsone → hemolytic anemia

• Anxiety, stress, and patient expectations can alter drug response
• Placebo responders may require lower doses

• Drug effects vary with circadian rhythm
• Antihypertensives: morning administration reduces peak blood pressure rise
• Corticosteroids: given in the morning to mimic cortisol rhythm, minimizing adrenal suppression

---

Q4. Explain Different Methods for Calculating Dosages in Children and Infants, Including Young's Rule, Clark's Rule, and Fried's Rule with Suitable Examples.

---

Introduction

---

1. Young's Rule (Age-Based, 1–12 years)

---

2. Dilling's Rule (Age-Based)

---

3. Clark's Rule (Weight-Based — Pounds)

---

4. Fried's Rule (For Infants < 1 year / up to 2 years)

---

5. Body Surface Area (BSA) Method — Most Accurate

• Mosteller formula: BSA = √[(height cm × weight kg) / 3600]
• DuBois formula: BSA = 0.007184 × height^0.725 × weight^0.425

---

6. Weight-Based Dosing (mg/kg)

• Total daily dose = 25 × 20 = 500 mg/day
• Each dose = 500/3 ≈ 167 mg TID

---

Summary Comparison

---

Q5. Discuss the Handling of Prescriptions and Its Legal Requirements, Common Errors in Prescriptions, Methods to Avoid Such Errors in Pharmacy Practice.

---

Handling of Prescriptions — Overview

---

Legal Requirements for Prescriptions

• Only a registered medical practitioner (MBBS, BDS, BAMS, BHMS, BVSc) can issue a valid prescription
• Registration number must appear on the prescription

• Schedule H drugs: Require a prescription; cannot be sold without one (e.g., antibiotics, antihypertensives)
• Schedule H1 drugs: Stricter controls — third-generation cephalosporins, antitubercular drugs, anti-HIV drugs. Prescription must be retained for 2 years; pharmacist's records mandatory
• Schedule X drugs (Narcotics/Psychotropics): Require special prescription forms; record books maintained; only 7 days' supply at a time

• Patient name, age, and address
• Date
• Name, dose, dosage form, and quantity of drug
• Prescriber's signature, name, qualification, and registration number

• Schedule H1 and X prescriptions must be recorded in a register (Form 17)
• Records must be maintained for a minimum of 2 years
• Subject to inspection by drug control authorities

• Schedule H and X drugs generally cannot be refilled without a fresh prescription
• Over-the-counter (OTC) medications in Schedule K can be sold without prescription

---

Common Errors in Prescriptions

• Most common source of dispensing errors
• Example: "Carboplatin" misread as "Cisplatin"

• Missing dose, route, frequency, or duration
• Missing patient age (critical for pediatric dosing)

• "U" for units → misread as "0" (e.g., 10U insulin → 100 units → 10× overdose)
• "QD" misread as "QID" → 4× intended dose
• "μg" misread as "mg" → 1000× overdose

• "1.0 mg" misread as "10 mg" → trailing zero should be avoided
• ".5 mg" (no leading zero) misread as "5 mg" → leading zero must be written as "0.5 mg"

• Look-Alike, Sound-Alike errors: Cephalexin/Cefazolin; Hydromorphone/Morphine; Glipizide/Glibenclamide

• Prescribing for the wrong patient
• Confusing drug names in a hurry

• Standard adult dose prescribed for a child or elderly patient
• Dose not adjusted for renal/hepatic impairment

• Prescribing interacting combinations without recognition (e.g., warfarin + NSAIDs)

• Prescribing a drug the patient is allergic to

• Errors in converting verbal/telephone orders to written form

---

Methods to Avoid Prescription Errors

• Eliminates illegibility; software alerts for interactions, allergies, and dose limits
• Barcode verification reduces dispensing errors

• Reduces brand-name confusion; internationally standardized

• Write "units" not "U"; write "micrograms" not "μg"; always use leading zeros (0.5 mg)

• Independent double-check for high-alert medications (heparin, insulin, chemotherapy)

• For verbal/phone orders, pharmacist reads back the order to the prescriber for confirmation

• Asking the patient what the drug is for (independent verification)
• "Three questions / three prime questions technique"

• Mandatory allergy check before dispensing

• Separate storage of LASA drugs; tall man lettering (e.g., hydrOXYzine vs. hydrALAzine)

• Pharmacist cross-checks all prescriptions against patient profile

• Regular training of both prescribers and pharmacists on error prevention

---

---

UNIT II: History of Pharmacy

---

Q1. Discuss the History, Background, and Development of the Pharmacy Profession — Highlighting Major Milestones in Its Evolution Globally and in India.

---

Ancient Period (Pre-history to 500 AD)

• Babylonia (3000 BC): The Ebers Papyrus (Egypt, ~1550 BC) is the oldest known pharmaceutical record, listing ~700 drug formulas and 800 remedies. Clay tablets from Babylon contain prescriptions.
• Vedic India (1500–600 BC): The Charaka Samhita and Sushruta Samhita are foundational texts of Ayurveda — describing hundreds of plant, animal, and mineral drugs. The concept of Dravyaguna (knowledge of medicinal substances) laid the groundwork.
• Ancient Greece: Hippocrates (~460–370 BC) — the "Father of Medicine" — separated medicine from religion and superstition. Dioscorides wrote De Materia Medica (1st century AD) — a compendium of ~600 plants used as drugs.
• Ancient Rome: Galen (~130–200 AD) — "Father of Pharmacy" — developed complex preparations known as Galenicals (tinctures, extracts, ointments); his principles influenced pharmacy for 1500 years.
• Arabia: Ibn Sina (Avicenna, 980–1037 AD) — Canon of Medicine — systematized drug knowledge; described quality testing and purity standards.

---

Medieval Period (500–1500 AD)

• Arab pharmacists established the first independent pharmacies separate from physician practices (~750 AD in Baghdad under Caliph Al-Mansur)
• First professional separation of pharmacy from medicine
• European apothecaries evolved as drug preparers distinct from physicians

---

Renaissance to Industrial Revolution (1500–1900)

• 1617: Society of Apothecaries of London founded — formal recognition of pharmacy as a profession
• 1820: First edition of the United States Pharmacopeia (USP) published
• 1858: British Pharmacopoeia (BP) published
• 1863: American Pharmaceutical Association (APhA) founded
• 1868: Pharmacy Act passed in Britain — standardized pharmacist qualifications
• 19th century: Synthetic chemistry began — coal tar derivatives, aspirin (1897 by Bayer)

---

20th Century — Modern Era

• 1928: Penicillin discovered by Alexander Fleming
• 1930s–1940s: Sulfonamides and antibiotics revolutionized therapy
• 1950s: Polio vaccine, cortisone; first modern clinical pharmacology
• 1960s–70s: Pharmacokinetics, biopharmaceutics developed as formal disciplines
• 1961: Thalidomide disaster → stricter drug regulation worldwide
• 1980s–90s: Biotechnology drugs (insulin, EPO, vaccines)
• 21st century: Personalized medicine, pharmacogenomics, targeted biologics

---

Development of Pharmacy in India

• Ayurvedic pharmacy dates back to Vedic period (1500 BC) — Charaka Samhita, Sushruta Samhita, Ashtanga Hridayam
• Nagarjuna (2nd century AD) introduced Rasa Shastra — use of metals and minerals in medicine (bhasmas)

• British East India Company brought Western medicine and pharmacy practices
• First Western-style pharmacy established in Madras (now Chennai) in the 18th century
• 1948: Drugs and Cosmetics Act enacted (1940) with rules in 1945, providing first legal framework for pharmacy

• 1948: Pharmacy Act enacted — defining qualifications and registration of pharmacists
• 1949: Pharmacy Council of India (PCI) established — regulatory body for pharmacy education
• 1955: Indian Pharmacopoeia (IP) first edition published
• 1963: All India Institute of Medical Sciences (AIIMS) included clinical pharmacy
• 1970: Patents Act passed — promoted Indian generic drug industry
• 1990s–2000s: India emerged as the world's largest generic drug exporter ("Pharmacy of the World")
• National Pharmaceutical Pricing Authority (NPPA) established to regulate drug prices
• Jan Aushadhi Scheme (2008): Government initiative for affordable generic medicines

• First B.Pharm program: Banaras Hindu University (1937)
• PCI curriculum revisions: Diploma, B.Pharm, M.Pharm, Pharm.D programs
• Introduction of Pharm.D (Doctor of Pharmacy, 2008) — clinical pharmacy training

---

Q2. Explain the Growth and Development of the Pharmaceutical Industry in India, Including Key Players and Contribution to Global Healthcare.

---

Historical Foundation

---

Phases of Growth

• Dominated by multinational companies (MNCs): Glaxo, Pfizer, Ciba-Geigy, Hoechst
• India largely imported bulk drugs
• Limited domestic manufacturing

• 1970 Patents Act: Process patents only (not product patents) → Indian firms could reverse-engineer drugs
• Domestic companies rapidly developed generic manufacturing capabilities
• Key companies emerged: Cipla, Dr. Reddy's Laboratories, Ranbaxy, Sun Pharma, Lupin
• Price controls via DPCO (Drug Price Control Order) reduced drug costs

• Liberalization (1991) opened the economy
• Indian companies began exporting generics globally — US FDA approvals sought
• India became a major supplier to regulated markets (US, EU, Australia)

• 2005: India amended Patents Act to comply with TRIPS — product patents now recognized
• Increased R&D investment; biosimilars and novel drug delivery systems
• India's pharma industry: 3rd largest by volume, 14th by value globally
• Contributes ~20% of global generic supply
• Supplies 60% of global vaccines (Serum Institute, Bharat Biotech)
• During COVID-19 pandemic: India supplied vaccines and generic drugs (Covaxin, Covishield) globally

---

Key Pharmaceutical Companies

---

India's Contribution to Global Healthcare

1. Affordable Medicines: Generic production dramatically reduced prices of HIV/AIDS drugs, making treatment accessible in Africa and Asia
2. Vaccine Supply: Serum Institute produces ~1.5 billion vaccine doses/year; supplied Covishield globally during COVID-19
3. Bulk Drug (API) Manufacturing: India is a major global supplier of Active Pharmaceutical Ingredients — ~20% global API supply
4. Regulatory Standards: Increasing number of US FDA-approved manufacturing plants (India has most outside the US)
5. Make in India: Government initiative to boost domestic pharmaceutical manufacturing — Production Linked Incentive (PLI) scheme for critical drugs

---

Q3. Describe the Development of the Indian Pharmacopoeia (IP), Including Its History, Objectives, and Significance in Drug Standardization.

---

Introduction

---

Historical Development

---

Structure and Contents of IP

1. General Notices: Interpretation of standards, general requirements
2. Monographs: Individual drug standards — description, identity tests, purity tests, assay methods
3. General Chapters: Methods of analysis (chromatography, spectroscopy, microbiology)
4. Appendices: Standard analytical procedures, reference standards
5. Herbal Drug Monographs: Standards for Ayurvedic and herbal drugs
6. Biological Monographs: Vaccines, blood products, biotechnology-derived products
7. Veterinary Monographs
8. Index

---

Objectives of the Indian Pharmacopoeia

1. Establish standards for identity, purity, and strength of drugs marketed in India
2. Ensure drug quality — provide analytical methods to test quality
3. Protect public health by preventing substandard and spurious drugs from reaching patients
4. Harmonize standards with international pharmacopoeias (USP, BP, EP) where appropriate
5. Regulate domestic production and imports — drugs must comply with IP or other accepted pharmacopoeial standards
6. Provide reference standards — IP Reference Standards (IPRS) issued for analytical purposes

---

Legal Status

• Under the Drugs and Cosmetics Act, 1940: A drug is considered substandard if it does not conform to IP standards
• IP standards are legally enforceable in India
• Manufacturers, importers, and dispensers must comply with IP specifications

---

Significance in Drug Standardization

1. Quality Assurance: Specifies minimum quality requirements for all drugs sold in India
2. Control of Spurious Drugs: IP methods allow rapid detection of adulteration or counterfeiting
3. National Standards: Provides India-specific standards for drugs widely used in the Indian subcontinent (including traditional medicines)
4. Harmonization: IP aligns with WHO International Pharmacopoeia, USP, and BP to facilitate international trade
5. Reference for Judiciary and Regulatory Bodies: Used by drug inspectors, courts, and the Drug Control General of India (DCGI) for enforcement
6. Education: IP is a standard reference in pharmacy education and practice

---

Indian Pharmacopoeia Commission (IPC)

• Established in 2010 as an autonomous institution under Ministry of Health
• Functions: Publication of IP; distribution of reference standards; training; harmonization with international pharmacopoeias
• Also publishes the National Formulary of India (NFI)

---

Q4. Compare the Major Pharmacopoeias — IP, BP, USP, and EP — Highlighting Their Features and Importance.

---

Introduction

---

Comparison Table

---

Key Features of Each

• Tailored to Indian context — includes drugs specific to tropical diseases (antimalarials, antifilarials)
• Covers Ayurvedic, Siddha, and Unani drug standards (unique among major pharmacopoeias)
• Cost-effective reference for developing countries
• Published every 5 years with supplements

• One of the oldest pharmacopoeias; highly authoritative globally
• Widely used in Commonwealth countries, Middle East, Southeast Asia
• Closely aligned with European Pharmacopoeia (BP adopts EP monographs)
• Well-recognized by WHO for international drug procurement

• World's most widely used pharmacopoeia; de facto international standard
• Combined with National Formulary (NF) as USP-NF
• Unique inclusion of dietary supplements and nutraceuticals
• Comprehensive general chapters on analytical methods, water activity, packaging
• 50+ language translations; used in over 140 countries
• Strong emphasis on bioavailability/bioequivalence standards (dissolution testing)

• Legally binding across all 38 member states of the Council of Europe
• Published in English and French
• Strongest international harmonization — coordinates with ICH (International Council for Harmonisation)
• Comprehensive biological and biotech monographs
• Reference for EU drug registration (CEP — Certificate of Suitability)

---

Importance of Pharmacopoeias

1. Quality Guarantee: Legal enforceable standards prevent substandard and counterfeit drugs
2. Trade Facilitation: Harmonized standards allow international drug trade
3. Patient Safety: Ensures every dose of a drug meets defined specifications
4. Regulatory Compliance: Drug approvals (ANDA, NDA, MA) require compliance with pharmacopoeial standards
5. Education & Research: Reference for pharmacists, chemists, and researchers

---

Q5. Write a Detailed Note on Extra Pharmacopoeia (Martindale) and INF (Indian National Formulary), Including Their Purpose, Contents, and Role in Pharmacy Practice.

---

A. Extra Pharmacopoeia (Martindale: The Complete Drug Reference)

• First published in 1883 by William Martindale, a London pharmacist
• Currently published by the Royal Pharmaceutical Society of Great Britain (RPSGB)
• Latest edition: 40th edition
• Available in print and online via MedicinesComplete (Pharmaceutical Press)

1. Drug Monographs (~6,000 drug substances):
   • Names: INN, brand names, synonyms
   • Chemical and pharmacopoeial information
   • Adverse effects and toxicity
   • Precautions and contraindications
   • Interactions
   • Pharmacokinetics
   • Uses and doses (clinical applications)
2. Supplementary Drugs: Drugs used in specific regions or limited use
3. Herbal Medicines: Phytochemical constituents, traditional uses, clinical evidence
4. Diagnostic Agents: Contrast media, radioactive isotopes
5. Vaccines and Immunologicals
6. Disease Treatment Summaries: Disease-oriented reviews with drug treatment options
7. Preparations (Proprietary names): Listed by country with active ingredients, dosage forms

• Drug information queries: Pharmacists use it to answer questions about unusual drugs, doses, interactions
• Clinical decision-making: Physicians/pharmacists refer to it for off-label uses, overdose management, pediatric doses
• Drug identification: Identify foreign drugs by brand name or active ingredient
• Research reference: Background information for formulary development, drug policy

---

B. Indian National Formulary (INF)

• Published by the Indian Pharmacopoeia Commission (IPC) with collaboration from MOHFW, Government of India
• First edition: 1954
• Recent editions: INF 2011, updated revisions available online
• Available free at: www.ipc.gov.in

1. Essential Medicines List (EML): Drugs selected based on efficacy, safety, and cost-effectiveness
2. Drug Monographs:
   • Indications
   • Contraindications and precautions
   • Side effects
   • Doses (adult and pediatric)
   • Formulations available
3. Prescribing Guidelines: Principles of rational drug use
4. Appendices:
   • Drugs in pregnancy and lactation
   • Drugs in renal and hepatic impairment
   • Drug interactions
   • Immunization schedules
5. Index: By generic name and therapeutic category

1. Promotes Rational Drug Use: Provides evidence-based prescribing guidance, reducing irrational polypharmacy
2. Essential Medicines Framework: Guides procurement for government hospitals and primary health centers (PHCs)
3. Standardizes Prescribing: Reduces variability in drug selection across India's diverse healthcare system
4. Educational Tool: Used in medical and pharmacy education for clinical pharmacology
5. Cost-Effectiveness: Encourages use of affordable, effective drugs over expensive brand-name alternatives
6. Reference for Drug Policy: Government drug procurement, NPPA price regulation, and Jan Aushadhi scheme are guided by INF-listed drugs
7. Herbal/Traditional Medicine Integration: Includes Ayurvedic drugs in some editions, recognizing India's pluralistic healthcare system
8. Patient Safety: Drug interaction tables, pregnancy/lactation cautions promote safer prescribing

---

Summary of All 10 Questions Answered

---

Note: All answers are written at the standard 15-mark detail level appropriate for B.Pharm / D.Pharm examinations in Pharmaceutics (Unit I & Unit II). Each answer contains definitions, detailed explanations, tables, formulas with worked examples, and clinical/practical significance as expected in university examinations.

---

PHARMACEUTICS — UNIT V & UNIT VI (15 Marks Each)

---

UNIT V — Q2. Gargles, Mouth Washes & Throat Paints

---

A. GARGLES

Definition

Formulation Components

Preparation

• Dissolve active ingredient in purified water with gentle heating if needed
• Add flavouring, sweetening agents and buffer
• Adjust pH to 6–7 (oral cavity compatible)
• Make up to volume; filter if required
• Label clearly: "Not to be swallowed — For gargling only"
• Concentrated preparations carry dilution instructions (e.g., dilute 1 in 8 with warm water)

Official Example — Compound Sodium Chloride Gargle (BNF)

• Sodium chloride 1.5% w/v
• Sodium bicarbonate 1% w/v
• Purified water to 100 mL
• Use: sore throat, post-tonsillitis

Therapeutic Uses

1. Throat infections (pharyngitis, tonsillitis)
2. Oral hygiene and mouth ulcers
3. Post-operative oral care
4. Reducing oral bacterial load

Precautions

• Never swallow
• Dilute concentrated solutions before use
• Avoid in children too young to gargle safely
• Potassium permanganate gargles — stain mucosa; use diluted (1:10,000)

---

B. MOUTH WASHES

Definition

Classification

1. Antiseptic mouth washes: Chlorhexidine 0.12–0.2%, cetylpyridinium chloride
2. Fluoride mouth washes: Sodium fluoride 0.05–0.2% (caries prevention)
3. Deodorant/Cosmetic: Zinc chloride, essential oils (Listerine® = thymol, eucalyptol, methyl salicylate, menthol)
4. Astringent: Tannic acid-based
5. Analgesic/Anti-inflammatory: Benzydamine HCl (Difflam®)

Formulation Components

Preparation Method

1. Dissolve antiseptic in warm purified water (or dissolve in ethanol first if poorly water-soluble)
2. Dissolve humectants (glycerin/sorbitol) separately
3. Mix both portions with stirring
4. Add flavouring agents and sweeteners
5. Adjust pH to 5.5–7.5 (near-neutral)
6. Make up to volume; filter if necessary
7. Fill into amber glass/HDPE bottles; label

Official Example — Compound Thymol Glycerin Mouth Wash (BPC)

• Thymol 0.05%, glycerin 10%, alcohol 5%, purified water to 100 mL
• Use: antiseptic, fresh breath, gingivitis

Therapeutic Uses

1. Prevention and treatment of gingivitis (chlorhexidine)
2. Caries prevention (fluoride rinses)
3. Oral candidiasis (nystatin mouth wash)
4. Post-extraction oral hygiene
5. Chemotherapy-induced mucositis
6. Deodorizing (halitosis)

Precautions

• Chlorhexidine: stains teeth with prolonged use; do not use with anionic surfactants (SLS toothpaste — incompatible)
• Alcohol-containing washes: avoid in children, recovering alcoholics
• Fluoride rinses: supervise children to prevent swallowing
• Not a substitute for brushing and flossing

---

C. THROAT PAINTS

Definition

Why Glycerin?

• Hygroscopic → demulcent, soothing
• High viscosity → prolongs contact with mucosa
• Preservative effect (high osmolarity)
• Sweet taste → improves palatability

Classification

1. Antiseptic throat paints: Mandl's paint (iodine + potassium iodide + glycerin)
2. Antifungal throat paints: Gentian violet paint 1% (for oral candidiasis)
3. Astringent throat paints: Tannic acid + glycerin
4. Compound throat paints: Compound benzoin throat paint (BPC)

Formulation Components

Official Formula — Mandl's Throat Paint

• Iodine 1.25 g
• Potassium iodide 2.5 g
• Water for injection 2.5 mL
• Peppermint oil 0.5 mL
• Glycerin to 100 mL

1. Dissolve potassium iodide in water
2. Dissolve iodine in the KI solution (forms KI₃ complex — more soluble)
3. Add peppermint oil
4. Make up to 100 mL with glycerin and mix well
5. Transfer to amber glass bottle with brush applicator

Another Formula — Compound Iodine Throat Paint (BPC)

• Iodine 1.25%, potassium iodide 2.5%, alcohol 0.5%, glycerin to 100 mL

Therapeutic Uses

1. Tonsillitis, pharyngitis, laryngitis
2. Oral thrush (gentian violet paint)
3. Aphthous ulcers (antiseptic paints)
4. Diphtheria carriers (iodine glycerin)

Precautions

• Apply with swab/brush; avoid excess application
• Iodine paints: avoid in hyperthyroid patients; can cause iodism with prolonged use
• Not for use in young children (choking risk with brush)
• Store in amber containers (iodine is photosensitive)

---

UNIT V — Q3. Ear Drops & Nasal Drops — Formulation, Evaluation, Therapeutic Uses & Precautions

---

A. EAR DROPS (Aural Preparations)

Definition

Therapeutic Uses

1. Antibacterial: Ciprofloxacin, gentamicin, neomycin — otitis externa
2. Antifungal: Clotrimazole — fungal otitis externa
3. Anti-inflammatory: Hydrocortisone (often combined with antibiotics)
4. Ceruminolytic (wax softening): Sodium bicarbonate 5%, almond oil, paradichlorobenzene
5. Local anaesthetic: Lidocaine — acute earache relief
6. Astringent: Aluminium acetate solution (Burow's solution) — otitis externa

Formulation Requirements

• Viscosity: Slightly viscous (glycerin/propylene glycol base) to prolong contact
• pH: 5–7 (outer ear is slightly acidic; low pH discourages bacterial/fungal growth)
• Vehicle: Purified water, glycerin, propylene glycol, or fixed oils (arachis, olive)
• Sterility: Preferred sterile (especially if TM may be perforated); at minimum, free from harmful organisms
• Preservative: Benzalkonium chloride (BAK) — but contraindicated if tympanic membrane (TM) is perforated; thimerosal as alternative

Standard Formula — Aluminium Acetate Ear Drops (BPC)

• Aluminium acetate solution 13 mL
• Glacial acetic acid 0.1 mL
• Purified water to 100 mL
• pH ~4.5 — astringent, antibacterial, antifungal

Standard Formula — Sodium Bicarbonate Ear Drops (IP)

• Sodium bicarbonate 5 g
• Glycerin 30 mL
• Purified water to 100 mL
• Use: cerumen removal (wax-softening)

Preparation

1. Calculate quantities
2. Dissolve active ingredient in appropriate solvent (water/glycerin)
3. Add preservative and pH-adjusting agent
4. Make up to volume
5. Filter through 0.45 μm membrane
6. Fill into sterile amber dropper bottles
7. Label: "For ear use only"

Evaluation of Ear Drops

Precautions

• Never use drops in perforated tympanic membrane unless specifically formulated for it (e.g., ciprofloxacin otic solution — safe with perforation; aminoglycosides — ototoxic if TM perforated)
• Warm the dropper bottle to body temperature before instillation (cold drops → vertigo)
• Tilt head to one side for 2–5 min after instillation
• Do not use cotton wool to block ear unless advised
• Benzalkonium chloride-containing drops: AVOID with perforation

---

B. NASAL DROPS

Definition

Therapeutic Uses

1. Decongestants: Xylometazoline, oxymetazoline — allergic rhinitis, common cold
2. Corticosteroids: Beclomethasone, fluticasone — allergic rhinitis, nasal polyps
3. Antibacterials: Neomycin, framycetin — bacterial rhinitis
4. Antihistamines: Azelastine — allergic rhinitis
5. Saline drops: Normal saline 0.9% — nasal irrigation, infant nasal congestion
6. Isotonic saline: Nasal mucosal hydration, crusting

Formulation Requirements

• Isotonicity: Solutions should be isotonic (0.9% NaCl equivalent) — hypertonic or hypotonic solutions damage ciliated nasal epithelium and impair mucociliary clearance
• pH: 5.5–7.5 (physiological nasal pH ~5.5–6.5)
• Buffering: Phosphate or borate buffer maintains pH
• Preservative: Benzalkonium chloride 0.01–0.02% (most common), thiomersal; but BAK can cause rebound congestion — minimize use
• Viscosity: Low (aqueous); slightly increased viscosity with CMC/HPMC prolongs contact
• Isotonicity: Achieved with NaCl, KCl, glucose, or sodium bicarbonate

Avoidance of Rebound Congestion

• Oxymetazoline/xylometazoline → vasoconstriction → if used >5 days, causes rhinitis medicamentosa (rebound congestion)
• Patients must be counseled to limit use to ≤3–5 days

Standard Formula — Simple Saline Nasal Drops

• Sodium chloride 0.9 g
• Purified water to 100 mL
• Sterile isotonic solution — safe for all ages

Standard Formula — Ephedrine Nasal Drops (BPC)

• Ephedrine HCl 1.0 g
• Sodium chloride 0.5 g (to adjust tonicity)
• Chlorhexidine acetate 0.025 g (preservative)
• Purified water to 100 mL

Preparation

1. Dissolve active drug in warm purified water
2. Add tonicity agent (NaCl) — calculate amount for isotonicity
3. Add buffer and preservative
4. Adjust pH to 5.5–7.0 with HCl or NaOH
5. Make up to volume; filter through 0.45 μm
6. Fill into sterile amber dropper bottles
7. Label: "Nasal drops — Not to be swallowed"

Evaluation of Nasal Drops

Precautions

• Do not use nasal drops for more than 3–5 consecutive days (decongestants)
• Blow nose before instillation
• Do not share dropper bottles (cross-infection risk)
• Use isotonic preparations for infants and prolonged treatment
• Oily nasal drops: avoid long-term use — risk of lipoid pneumonia if aspirated
• Label: "For nasal use only"

---

UNIT V — Q4. Lotions & Liniments — Differentiation, Formulation, Preparation & Uses

---

Comparison at a Glance

---

A. LOTIONS

Definition

Types of Lotions

1. Aqueous lotions: Zinc oxide lotion
2. Alcoholic lotions: Calamine lotion with alcohol
3. Suspension lotions: Calamine lotion (zinc oxide + calamine suspension)
4. Emulsion lotions: Benzyl benzoate application (o/w emulsion)

Formulation Components

Official Formula — Calamine Lotion (BPC)

• Calamine 15 g
• Zinc oxide 5 g
• Glycerin 5 mL
• Bentonite 3 g
• Sodium citrate 0.5 g
• Liquefied phenol 0.5 mL
• Purified water to 100 mL

1. Triturate calamine and zinc oxide with glycerin to form a smooth paste
2. Mix bentonite with water to form a gel; add sodium citrate
3. Incorporate the paste into bentonite gel gradually
4. Add phenol (dissolved in a little water) and make up to volume
5. Bottle in amber glass; label: "Shake well before use — External use only"

Therapeutic Uses of Lotions

1. Calamine lotion — pruritus (itching), sunburn, chickenpox, insect bites
2. Benzyl benzoate lotion 25% — scabies treatment
3. Whitfield's lotion — fungal skin infections
4. Salicylic acid lotion — acne, psoriasis (keratolytic)
5. Clotrimazole lotion — cutaneous candidiasis

Precautions

• Shake well before use (suspensions)
• Avoid contact with eyes
• Do not apply to broken or infected skin (unless directed)
• Benzyl benzoate: dilute to 12.5% for children

---

B. LINIMENTS

Definition

Types of Liniments

1. Oily liniments: Fixed oil + active ingredient; e.g., Camphor liniment
2. Alcoholic liniments: Alcohol + active ingredient; fast penetration; rubefacient action; e.g., Turpentine liniment
3. Emulsion liniments: o/w or w/o emulsions; e.g., White liniment
4. Soap liniments: Soap (potassium oleate) as emulsifying base; e.g., Opodeldoc

Formulation Components

Mechanism of Action of Counter-Irritants

Official Formula — Turpentine Liniment (BPC)

• Turpentine oil 65 mL
• Camphor 5 g
• Soft soap 7.5 g
• Water to 100 mL
• Type: soap liniment (emulsion)

1. Dissolve camphor in turpentine oil
2. Dissolve soft soap in warm water
3. Gradually add turpentine-camphor to soap solution with constant stirring
4. Mix to form stable emulsion; make up to 100 mL
5. Transfer to amber bottle; label: "External use only — Apply with friction"

Official Formula — Methyl Salicylate Liniment

• Methyl salicylate 25 mL
• Camphor 25 g
• Arachis oil to 100 mL
• Preparation: Simple mixing; methyl salicylate and camphor dissolve in oil

Therapeutic Uses

1. Rheumatic pain, arthritis — deep-penetrating analgesics (methyl salicylate)
2. Muscular pain, strains, sprains — camphor, turpentine
3. Neuralgia — rubefacient action diverts pain sensation
4. Sports injuries — post-exercise muscle soreness
5. Chest rubs — camphor/eucalyptus for nasal congestion (when used externally)

Precautions

• Apply only externally; do not apply near eyes or mucous membranes
• Do not apply to broken or inflamed skin
• Methyl salicylate: toxic if ingested — particularly dangerous for children
• Avoid tight bandaging after application (trapping heat → burning)
• Alcoholic liniments: flammable — keep away from open flames

---

UNIT V — Q5. Enemas & Collodions — Types, Formulation, Preparation & Uses

---

A. ENEMAS

Definition

Classification of Enemas

• Purpose: Bowel evacuation (constipation, pre-operative bowel prep, fecal impaction)
• Examples:
  • Soap water enema (SWE): 1–2% soft soap solution, 1–2 litres
  • Glycerin enema: glycerin 30 mL in warm water (irritant, draws water into colon)
  • Phosphate enema (Fleet®): Sodium dihydrogen phosphate + disodium hydrogen phosphate — osmotic purgative
  • Micro-enema: Sodium citrate + sodium lauryl sulfoacetate + glycerin (5 mL; e.g., Micralax®)

• Purpose: Drug is retained for local or systemic absorption
• Examples:
  • Steroid enema: Prednisolone sodium phosphate 20 mg/100 mL — for ulcerative colitis
  • Mesalazine enema: 1–4 g — inflammatory bowel disease
  • Nutritive enema: Glucose + saline — when oral/IV feeding not possible
  • Aminophylline retention enema (for severe asthma — historical)

• Purpose: Expel intestinal parasites
• Example: Quassia enema (pinworms/threadworms)

• Barium sulphate suspension enema — radiographic examination of colon

• Ice cold water — for hyperpyrexia (rarely used now)

• Arachis oil 130 mL — soften impacted feces; retained for several hours

---

Formulation Requirements for Enemas

• pH: Near physiological (7.2–7.4) for retention enemas; less critical for evacuant
• Tonicity: Isotonic for retention; hypertonic for osmotic evacuant effect
• Temperature: Warmed to body temperature (37°C) before administration
• Volume: Evacuant — 0.5–1 L; Retention — 50–100 mL; Micro-enema — 5 mL
• Sterility: Not required for most enemas; sterile if rectally absorbed for systemic effect
• Vehicles: Water, saline, oils

Official Formula — Sodium Phosphate Enema (IP/BPC)

• Disodium hydrogen phosphate 12H₂O — 10.24 g
• Sodium dihydrogen phosphate 2H₂O — 3.84 g
• Purified water to 100 mL
• Use: evacuant — osmotic mechanism draws water into colon

Preparation of Evacuant Enema

1. Dissolve sodium phosphate salts in warm purified water
2. Adjust to 100 mL; check pH (4.5–5.5 is acceptable for this formula)
3. Fill into single-dose squeezable plastic container (118–133 mL)
4. Label: "For rectal use only — Warm before use"

Therapeutic Uses Summary

Precautions

• Use rectal tube lubricated with KY jelly; patient lies on left side (Sims' position)
• Do not force the tube — rectal perforation risk
• Warm to body temperature (cold enemas → severe colicky pain and cramping)
• Avoid repeat phosphate enemas in renal impairment (hyperphosphatemia risk)
• Sodium phosphate enema: contraindicated in sodium-restricted patients, congestive cardiac failure
• Sterile technique for retention enemas containing steroids

---

B. COLLODIONS

Definition

Types of Collodions

• Contains: Pyroxylin 2.5%, camphor 2%, castor oil 3%, ether 62%, ethanol 31%
• Camphor and castor oil act as plasticizers → film is flexible (does not crack)
• Use: Protective coating for skin; vehicle for keratolytic agents

• Pyroxylin 4% in ether-alcohol without plasticizers
• Forms a rigid film → may crack with movement
• Now rarely used; replaced by flexible collodion

• Salicylic acid 12–16.7% w/v in flexible collodion
• Use: Wart treatment (verruca vulgaris) and corn removal
• Keratolytic action: salicylic acid softens and destroys hyperkeratotic tissue

• Salicylic acid 16.7% + lactic acid 16.7% in flexible collodion
• Use: Plantar warts, common warts

Formulation Components

Preparation of Flexible Collodion (BPC)

1. Weigh pyroxylin carefully (FLAMMABLE — no open flames)
2. Dissolve in diethyl ether in a closed container
3. Add ethanol and mix well (closed system — ether vapor)
4. Add camphor and castor oil (pre-dissolved in a little ethanol)
5. Make up to volume with ether-alcohol mixture
6. Filter through glass wool (not paper — incompatible)
7. Transfer to well-closed, air-tight amber glass bottles
8. Label: "Highly Flammable — Keep away from flame — External use only"

Preparation of Salicylic Acid Collodion

1. Dissolve salicylic acid in flexible collodion (NaOH must NOT be used — causes decomposition)
2. Stir gently until fully dissolved (low-speed mixing, closed container)
3. Fill into small glass bottles with brush applicator
4. Label: "Apply with brush — Avoid normal skin — Flammable"

Therapeutic Uses

Advantages

• Provides mechanical protection to wounds
• Ensures prolonged contact of drug with skin (film traps drug)
• Easy to apply; dries rapidly
• Transparent film allows wound observation

Precautions

• HIGHLY FLAMMABLE (ether content) — no smoking, open flames, or heat during preparation or application
• Avoid applying near eyes or mucous membranes
• Salicylic acid collodion: protect surrounding healthy skin with petroleum jelly before application (to prevent keratolytic damage to normal tissue)
• Do not use on infected or inflamed skin
• Seal bottles tightly — ether evaporates rapidly
• Keep refrigerated to retard evaporation

---

---

UNIT VI — Q1. Biphasic Dosage Forms — Definition, Advantages & Disadvantages of Suspensions & Emulsions

---

Definition of Biphasic Dosage Forms

1. Suspensions — Solid dispersed in liquid (solid:liquid system)
2. Emulsions — Liquid dispersed in liquid (liquid:liquid system)

---

A. SUSPENSIONS

Definition

Advantages of Suspensions

1. Overcome solubility limitations: Drugs that are insoluble or poorly soluble in water can be administered as suspensions (e.g., antacids — aluminium hydroxide, zinc oxide)
2. Improved stability: Some drugs are chemically unstable in aqueous solution but stable in suspension form (e.g., amoxicillin oral suspension — reconstituted just before use)
3. Masking bitter/unpleasant taste: Insoluble particles do not dissolve in saliva → less taste perception (e.g., chloramphenicol palmitate — insoluble, tasteless; vs. chloramphenicol sodium succinate — soluble, bitter)
4. Prolonged duration of action: Depot suspensions provide slow drug release (e.g., insulin zinc suspension, depot corticosteroid injections)
5. Topical use: Protective and soothing coating on skin/mucosa (e.g., calamine lotion, antacid suspension)
6. Flexibility of dosing: Liquid form allows dose adjustment (especially for pediatric patients — spoon or syringe dosing)
7. Alternative to tablets/capsules: For patients who cannot swallow solid dosage forms
8. Higher bioavailability than tablets in some cases (large surface area of dispersed particles)

Disadvantages of Suspensions

1. Physical instability: Sedimentation occurs over time due to gravity (Stokes' Law); may result in caking (hard, irreversible sediment)
2. Inaccurate dosing: If not shaken adequately before use, dose variation occurs (settled particles = concentrated dose in bottom; clear supernatant = sub-therapeutic dose)
3. Poor palatability: Gritty texture if particle size is large; chalky mouthfeel
4. Bulky: Large volume — inconvenient to carry and store compared to tablets
5. Limited stability: Aqueous suspensions support microbial growth — requires preservative; shelf-life typically 2–5 years (dry powder for reconstitution)
6. Redispersion problems: Caking (when particles fuse into hard cake) makes redispersion impossible — therapeutic failure
7. Not suitable for all routes: Cannot be given IV (particle embolism risk) — only SC/IM acceptable if specially formulated
8. Manufacturing complexity: Requires controlled particle size reduction (micronization), selection of suspending agents, and stability testing

---

B. EMULSIONS

Definition

Types:

• O/W (Oil-in-Water): Oil droplets in water → miscible with water → washable; for internal use
• W/O (Water-in-Oil): Water droplets in oil → miscible with oil → used topically (cold creams, barrier creams)
• Multiple emulsions: W/O/W or O/W/O — used for sustained release, vaccine adjuvants

Advantages of Emulsions

1. Improves oral bioavailability of lipophilic drugs: Emulsification enhances GI absorption of poorly water-soluble drugs (e.g., cyclosporine — Neoral® oral emulsion)
2. Masking unpleasant taste/odor: Oily drugs (castor oil, fish liver oil) are more palatable in O/W emulsion form with flavoring
3. Accurate dose measurement: Uniform liquid form allows precise dosing for both adults and children
4. Topical drug delivery: W/O emulsions (cold creams) occlude skin, hydrate, and enhance drug penetration
5. Intravenous lipid emulsions: Provide parenteral nutrition (Intralipid® — 10–20% soybean oil emulsion); deliver lipophilic drugs IV (propofol — 1% in soybean oil emulsion)
6. Sustained release potential: Multiple emulsions and microemulsions can provide controlled release
7. Protection of drug from degradation: Oily phase protects acid-labile drugs from aqueous environment
8. Versatility: Can be formulated as oral liquids, topical creams/lotions, IV injections, rectal preparations
9. Self-emulsifying drug delivery systems (SEDDS): Enhance bioavailability of BCS Class II/IV drugs

Disadvantages of Emulsions

1. Thermodynamic instability: All emulsions are inherently unstable — given enough time they will separate (Gibbs free energy of mixing is positive)
2. Creaming: Globules aggregate and rise (O/W) or sink (W/O) — does not break emulsion but leads to uneven dosing; reversed by shaking
3. Coalescence: Globules merge → larger droplets → irreversible if the film breaks → phase separation (breaking/cracking) — irreversible
4. Flocculation: Loose aggregation of globules → precursor to coalescence
5. Phase inversion: O/W emulsion converts to W/O (or vice versa) due to temperature, electrolytes, or excess dispersed phase
6. Microbial contamination: Aqueous phase and oily phase both support microbial growth → requires preservative (methylparaben, propylparaben — O/W; sorbic acid)
7. Incompatibilities: Emulsifying agents may interact with cationic drugs or electrolytes → emulsion destabilization
8. Manufacturing complexity: Requires specific equipment (colloid mill, high-pressure homogenizer, ultrasonicator); controlled conditions for stable globule size
9. Bulky preparation: Inconvenient vs. tablets/capsules
10. Short shelf life: Typically 2–3 years; IV emulsions — very short (must be used soon after manufacture)

---

UNIT VI — Q2. Classification of Suspensions & Emulsions — Characteristics with Examples

---

A. CLASSIFICATION OF SUSPENSIONS

1. Based on Route of Administration

2. Based on Electrokinetic Nature

3. Based on Proportion of Solid

• Dilute suspensions: <2% solids — e.g., insulin injection
• Concentrated suspensions: >50% solids — e.g., zinc oxide paste for topical use, barium sulfate (oral/rectal)

4. Based on Particle Size

• Colloidal suspensions: Particle size < 0.1 μm (technically approaching colloids)
• Coarse suspensions: Particle size 0.5–10 μm — most pharmaceutical suspensions
• Very coarse: > 50 μm — not ideal for pharmaceutical use

Characteristics of a Good Suspension

1. Particles settle slowly; redisperse uniformly on shaking
2. Uniform particle size (narrow distribution)
3. Does not cake (form hard sediment)
4. Adequate viscosity for pourability
5. Chemically stable; does not change pH over shelf life
6. Pleasing appearance; good palatability
7. Pours easily from bottle; measures accurately

---

B. CLASSIFICATION OF EMULSIONS

1. Based on Dispersed Phase

2. Based on Globule Size

3. Based on Route of Administration

• Oral emulsions: Castor oil emulsion, fish liver oil emulsion
• Topical emulsions: Creams (vanishing cream O/W; cold cream W/O), lotions
• Parenteral emulsions: Intralipid® (soybean oil 10–20%, O/W — for IV nutrition); propofol
• Rectal emulsions: Arachis oil enema

Characteristics of a Good Emulsion

1. Small, uniform globule size (< 5 μm for most pharmaceutical uses; < 0.5 μm for IV)
2. Does not cream, coalesce, or phase-invert during shelf life
3. Easily redispersible if creaming occurs
4. Appropriate viscosity
5. Sterile (parenteral); low microbial counts (topical/oral)
6. Chemically stable active ingredient
7. Pleasing appearance and palatability (oral)

---

UNIT VI — Q3. Formulation of Suspensions — Role of Excipients & Stability

---

Introduction

---

Role of Various Excipients in Suspension Formulation

1. Suspending Agents (Rheological Modifiers)

2. Wetting Agents (Surfactants)

3. Flocculating Agents (Controlled Flocculation)

• Electrolytes: Sodium/potassium chloride — reduce zeta potential
• Ionic surfactants
• Polymers (at specific concentrations)
• Target zeta potential: -20 to -5 mV (mild flocculation) → soft, dispersible sediment

4. pH-adjusting Agents / Buffers

• Maintain pH for drug stability, palatability, and preservative effectiveness
• Citrate buffer (pH 4–6), phosphate buffer (pH 6–8)
• pH affects ionization and thus solubility; also affects zeta potential (surface charge)

5. Preservatives

6. Sweeteners and Flavoring Agents

• Sucrose syrup 60–70% in oral suspensions (also increases viscosity)
• Sorbitol solution (non-cariogenic alternative)
• Flavors: orange, strawberry, peppermint (added at low concentrations 0.01–0.1%)
• Artificial sweeteners: saccharin, aspartame (for sugar-free preparations)

7. Colorants

---

Factors Affecting Stability of Suspensions

Physical Stability Factors:

• Smaller particles → slower sedimentation (Stokes' Law); but also → greater risk of Ostwald ripening
• Micronization (< 10 μm) improves dispersion but increases surface energy → risk of caking
• Optimal: 1–5 μm

• Higher viscosity → slower sedimentation
• Too viscous → difficult to pour, dose inaccurately

• High zeta potential (> ±30 mV) → deflocculated → hard cake
• Optimal zeta potential for controlled flocculation → soft, redispersible sediment

• Minimizing density difference between particles and vehicle reduces sedimentation

• High temperature → reduced viscosity → increased sedimentation
• Freeze-thaw cycles → can cause aggregation or changes in crystal form (polymorphic conversion)

• High electrolytes → reduce zeta potential → promote flocculation (can be beneficial for controlled flocculation or disastrous if leads to caking)

• Wide-mouth bottles allow vigorous shaking
• Amber glass or opaque HDPE → protects from light

Chemical Stability Factors:

• pH drift → may alter solubility and drug form
• Oxidation (antioxidants: ascorbic acid, sodium metabisulfite)
• Hydrolysis — keep water activity low; use dry powder for reconstitution

---

Evaluation of Suspensions

---

UNIT VI — Q4. Formulation of Emulsions — Emulsifying Agents & Methods of Preparation

---

Introduction

---

Emulsifying Agents — Classification & Role

1. Natural Emulsifying Agents

2. Semi-synthetic Emulsifying Agents

• HPMC, Na-CMC, HEC — cellulose derivatives; O/W emulsifiers/stabilizers

3. Synthetic Emulsifying Agents (Surfactants)

• HLB 3–6 → W/O emulsifiers
• HLB 8–18 → O/W emulsifiers
• HLB 7–9 → wetting agents
• HLB > 16 → solubilizers

4. Finely Divided Solid Particles (Solid Particle Emulsifiers)

• Bentonite — O/W (particle preferentially wetting by water)
• Magnesium aluminum silicate — O/W
• Carbon black — W/O

---

Method of Preparation

Principle

A. Dry Gum Method (Continental / 4:2:1 Method)

1. Weigh 4 parts oil (e.g., 40 mL)
2. Add 1 part dry acacia powder (e.g., 10 g) to the oil in a dry mortar; mix to a uniform oily mass
3. Add 2 parts water (e.g., 20 mL) all at once and triturate vigorously and continuously with a pestle
4. A clicking sound indicates primary emulsion formation; appearance turns creamy white
5. Dilute progressively with remaining aqueous phase (small additions with mixing)
6. Transfer to graduated cylinder; make up to final volume; shake

B. Wet Gum Method (English Method)

1. Dissolve 1 part acacia in 2 parts water → form mucilage
2. Add 4 parts oil gradually, in small portions, with continuous trituration
3. After each addition of oil, triturate until uniform before adding more
4. Continue until all oil is incorporated
5. Transfer and make up to volume

C. Bottle Method (Forbes Method)

1. Place dry gum in a bottle
2. Add oil; shake to disperse gum
3. Add water all at once; shake vigorously
4. Dilute with aqueous phase

D. Beaker Method

1. Heat oil phase to 70–75°C with oil-soluble emulsifier (Span)
2. Heat water phase to same temperature with water-soluble emulsifier (Tween) and other water-soluble excipients
3. Add aqueous phase to oily phase (or vice versa, depending on desired emulsion type) with continuous mechanical stirring
4. Stir until cool; homogenize if required
5. Add heat-sensitive ingredients (fragrance, preservative) below 40°C

E. In Situ (Nascent) Soap Method

• E.g., Lime water + arachis oil → calcium oleate soap (W/O) → application in Lime Liniment

F. High-Energy Equipment

• Colloid mill: Passes emulsion through narrow gap between rotor and stator at high speed
• High-pressure homogenizer: Forces through narrow orifice (< 1 μm droplets) — used for IV emulsions
• Ultrasonic homogenizer: High-frequency vibrations → micronized droplets
• Microfluidizer: Used for nanoemulsions

---

Formulation of Oral Emulsion — Practical Example

• Liquid paraffin 500 mL
• Acacia powder 125 g (1/4 of oil weight)
• Chloroform water (preservative) to 1000 mL
• Saccharin sodium 0.1 g
• Peppermint oil 0.5 mL

1. Place acacia and liquid paraffin in dry mortar
2. Add 250 mL water all at once, triturate vigorously → primary emulsion
3. Transfer to cylinder; add saccharin and peppermint (dissolved in small water)
4. Make up to 1000 mL with chloroform water
5. Bottle and label: "Shake well before use"

---

UNIT VI — Q5. Evaluation & Stability of Emulsions — Including Tests to Identify Emulsion Type

---

A. EVALUATION OF EMULSIONS

1. Physical Evaluation

• Color, odor, taste, consistency
• Should be homogeneous; no visible phase separation or grittiness

• Measured by: Laser diffraction (most common), dynamic light scattering (DLS), optical microscopy
• Target: D₅₀ < 5 μm (oral); D₅₀ < 0.5 μm (IV emulsions — critical for safety)
• Polydispersity Index (PDI): < 0.2 for monodisperse; < 0.3 acceptable for pharmaceutical emulsions

• Measured with Brookfield viscometer (rotational), Ostwald viscometer (dilute systems)
• Important for stability, pourability, and patient acceptance

• Measured with calibrated pH meter
• Important for drug stability, preservative effectiveness, and skin compatibility (topical: pH 4.5–6.5)

• Measured by pycnometer or densitometer
• Used to calculate content uniformity

• Measured by electrophoresis or Zetasizer (laser Doppler)
• Indicates electrical stability of emulsion
• |Zeta potential| > ±30 mV = stable emulsion
• Values approaching 0 = tendency to flocculate/coalesce

---

2. Stability Testing

• Drug assay by HPLC at 0, 3, 6, 12, 24 months
• Peroxide value (for oils susceptible to oxidation)
• pH stability (should remain within ±0.5 pH units)

• Total aerobic microbial count (TAMC): ≤ 100 CFU/mL (oral); ≤ 10 CFU/mL (ophthalmic)
• Preservative efficacy test (PET) — USP <51>/BP

• ICH guidelines: 40°C/75% RH for 6 months (accelerated); 25°C/60% RH for 24 months (long-term)

---

3. Chemical Evaluation

• Assay: HPLC, UV spectrophotometry for drug content (90–110%)
• Preservative assay: Ensure adequate preservative levels throughout shelf life
• Oxidation products: Particularly for oils (rancidity — peroxide value < 10 meq/kg)
• Acid value: Monitor hydrolysis of oils

---

B. TESTS TO IDENTIFY THE TYPE OF EMULSION (O/W vs. W/O)

1. Dilution Test

• Add a small amount of water to the emulsion; mix gently
• O/W emulsion: Miscible with water → uniform dilution (continuous phase is water)
• W/O emulsion: Immiscible with water → separates, appears "greasy" or chunky

• W/O: Miscible with oil → dilutes uniformly
• O/W: Immiscible with oil → separates

2. Conductivity Test (Electrical Conductivity)

• Water conducts electricity; oil does not
• Connect emulsion to an electrical circuit with a light bulb
• O/W emulsion: Conducts electricity → bulb lights up ✓
• W/O emulsion: Does not conduct → bulb stays dark ✗

3. Dye Solubility Test

• If water-soluble dye colors the continuous (external) phase → O/W
• If oil-soluble dye colors the continuous phase → W/O

4. Fluorescence Test

• Many oils fluoresce under UV light
• W/O emulsion: Entire emulsion fluoresces under UV
• O/W emulsion: Only globules fluoresce; background (continuous water phase) does not

5. Cobalt Chloride Paper Test

• Anhydrous CoCl₂ paper is blue; turns pink in presence of water
• O/W emulsion: Paper turns pink (aqueous external phase contacts paper)
• W/O emulsion: Paper remains blue (oil external phase; water is internal)

6. Creaming Direction Test (Ultracentrifugation)

• In an ultracentrifuge: denser phase moves to bottom; lighter phase moves to top
• O/W: oil globules (less dense) cream upward; water stays below
• W/O: water globules (denser) sediment downward; oil remains above

Summary Table — Type Identification Tests

---

C. MECHANISMS OF EMULSION INSTABILITY (Stability Phenomena)

1. Creaming

• Upward movement of oil globules (O/W) or downward of water globules (W/O) due to density difference
• Reversible — redispersed by shaking
• Governed by Stokes' Law
• Prevention: reduce globule size; increase viscosity of continuous phase; match densities

2. Flocculation

• Loose aggregation of globules without merging
• Increases creaming rate (larger effective particle)
• Can be reversible
• Prevention: increase zeta potential; add polymeric stabilizers

3. Coalescence

• Merging of globules into larger ones → progressive phase separation
• Irreversible — cannot be restored by shaking
• Prevention: strong emulsifying agent film; adequate concentration of emulsifier; avoid excessive temperature; add stabilizers (HPMC, Carbopol)

4. Ostwald Ripening

• Small droplets dissolve and re-deposit onto larger ones (driven by Laplace pressure difference)
• Results in gradual increase in mean globule size
• Prevention: narrow initial globule size distribution; add water-insoluble compound (e.g., hexadecane) to oil phase (thermodynamic barrier)

5. Phase Inversion

• O/W converts to W/O (or vice versa) — triggered by:
  • Temperature change (phase inversion temperature — PIT)
  • Electrolyte addition (salting out of emulsifier)
  • Exceeding critical phase volume ratio (> 74% dispersed phase)
• Prevention: avoid extreme temperatures; control electrolyte levels; maintain phase ratio

6. Breaking (Cracking)

• Complete and irreversible phase separation
• Cause: coalescence taken to completion; incompatibility of emulsifier with added drugs/salts
• Prevention: avoid incompatible additives; maintain appropriate HLB; correct manufacturing

---

All 9 questions answered at full 15-mark examination standard for B.Pharm / D.Pharm Pharmaceutics — Unit V & Unit VI. Each answer includes definitions, classification, formulation, preparation method, excipient roles, evaluation tests, and therapeutic uses/precautions as appropriate for 15-mark long answers.