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Explain Segment I and Segment III Female Reproductive Toxicity Study in detail.

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Segment I Segment III female reproductive toxicity study preclinical pharmacology explained

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https://www.frontagelab.com/blog/a-complete-overview-of-dart…

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Segment I fertility early embryonic development Segment III pre postnatal development study ICH S5 female reproductive toxicology detailed

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https://database.ich.org/sites/default/files/S5-R3_Step4_Gui…

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I now have comprehensive information from ICH S5(R3) and DART regulatory guidelines. Let me compile the full, detailed answer.

Segment I and Segment III Female Reproductive Toxicity Studies

These studies are part of the DART (Developmental and Reproductive Toxicology) preclinical testing program required by regulatory agencies (ICH S5, FDA, EMA) before drugs can be used in women of childbearing potential. The three-segment framework covers the entire reproductive cycle from gamete maturation through postnatal development of offspring.

Background: The Segment Framework

The traditional segment classification maps drug exposure to reproductive life stages:
StageLife Event
APre-mating / gamete maturation
BConception, implantation
COrganogenesis
DClosure of hard palate / late fetal development
EParturition (birth)
FWeaning / postnatal development
  • Segment I (FEED) covers Stages A-B
  • Segment II (EFD) covers Stages C-D
  • Segment III (PPND) covers Stages C-F

SEGMENT I - Fertility and Early Embryonic Development (FEED) Study

Purpose

Segment I evaluates whether a compound adversely affects gamete maturation, mating behavior, fertilization, preimplantation embryo development, and implantation. For females specifically, it targets events from follicle maturation through blastocyst implantation in the uterus.

Species Used

  • Primarily rodents (rats preferred)
  • Non-rodent species may be added if data warrants

Female-Specific Dosing Timeline

  • Treatment begins 2 weeks before mating (approximately 2 estrous cycles) to capture the window of folliculogenesis and oocyte maturation
  • Dosing continues through mating and up to gestational day 6-7 (implantation)
  • Some designs extend dosing to GD 13-15 to differentiate live implantations from resorption sites

Female-Specific Endpoints Assessed

1. Estrous Cyclicity
  • Vaginal cytology is examined daily during pre-mating and mating phases
  • Evaluates regularity, phase duration, and any disruption of the estrous cycle
  • Disruption indicates hypothalamic-pituitary-gonadal (HPG) axis interference
2. Mating Performance
  • Females are co-housed with untreated males (or treated males in full fertility studies)
  • Pre-coital interval (days from pairing to mating) is recorded
  • Copulation index = % females that mated / % females paired
3. Fertility Index
  • % of mated females that became pregnant
  • Indicates whether successful fertilization occurred
4. Ovarian Function
  • Corpora lutea count (per ovary) - indicates number of released eggs
  • Pre-implantation loss = (corpora lutea - implantation sites) / corpora lutea × 100
  • Ovarian weight and histopathology
5. Uterine Endpoints
  • Total implantation sites
  • Live implantations
  • Early resorptions (dead implants before GD 13)
  • Post-implantation loss rate
6. Histopathology
  • Ovaries, uterus, vagina, oviducts - examined microscopically
  • Follicle counts (primordial, primary, secondary, Graafian follicles) - identifies follicular depletion or atresia
  • Corpus luteum quality
7. Tubal Transport
  • Evaluates oviductal function (movement of fertilized egg toward uterus)

Key Calculations in Segment I (Female)

IndexFormula
Fertility index(Pregnant females / Mated females) × 100
Pre-implantation loss(Corpora lutea - Implants) / Corpora lutea × 100
Post-implantation loss(Implants - Live fetuses) / Implants × 100

Dose Selection

  • Minimum 3 dose groups + vehicle control
  • Highest dose: maximally tolerated dose (MTD) or limit dose (1000 mg/kg)
  • NOAEL and LOAEL are derived from these dose groups

Regulatory Context

Under ICH S5(R3), Segment I FEED results in rodents are required before Phase 2 trials in women of childbearing potential (WOCBP). It is often run in parallel with the Segment II embryo-fetal development (EFD) study.

SEGMENT III - Pre- and Postnatal Development (PPND) Study

Purpose

Segment III assesses the effects of gestational and lactational maternal exposure on:
  1. The pregnant/lactating female
  2. Parturition (the birth process)
  3. Offspring development from birth through sexual maturity and reproductive capability
It is the most comprehensive of the three segments as it spans from implantation (GD 6-7) all the way through weaning (postnatal day ~21) and beyond.

Species Used

  • Primarily rats (rodents)
  • Non-human primates (NHPs) may be used for biologics (ePPND study)
  • Rabbits are typically used for Segment II, not Segment III

Female Dosing Timeline

  • Dosing begins on Gestational Day 6-7 (post-implantation, to avoid confounding implantation effects which are Segment I territory)
  • Continues through parturition and lactation until postnatal day (PND) 21 (weaning)
  • This covers: late organogenesis, fetal growth, birth, and nursing

Female-Specific Endpoints - Maternal Assessment

1. General Toxicity Monitoring
  • Body weight and food consumption throughout gestation and lactation
  • Clinical observations for signs of enhanced toxicity in the pregnant/lactating state (pregnant animals may be more susceptible due to altered PK/PD)
2. Gestation Length
  • Number of days from confirmed mating to delivery
  • Prolonged or shortened gestation indicates interference with hormonal parturition signals (prostaglandins, oxytocin, progesterone withdrawal)
3. Parturition Assessment
  • Duration and ease of delivery
  • Dystocia (difficult or obstructed labor)
  • Number of stillbirths at birth
  • Cannibalism behavior by dam (reflects maternal stress/neglect)
4. Lactation and Maternal Behavior
  • Nursing behavior and litter care
  • Milk production (assessed indirectly by pup weight gain)
  • Milk yield via pup weight on PND 1 vs. PND 4 (pre-weaning weight gain index)
5. Post-Weaning Maternal Recovery
  • Uterine involution
  • Return to estrous cyclicity after weaning

Offspring (F1 Generation) Endpoints

Although these focus on the pups, they reflect maternal exposure effects:
Survival and Growth
  • Viability index: pups alive on PND 4 / total born alive × 100
  • Weaning index: pups alive at PND 21 / pups alive on PND 4 × 100
  • Pup body weights at PND 1, 4, 7, 14, 21 - tracks growth trajectory
Developmental Landmarks (Sex-specific)
  • Vaginal opening (females) - indicator of sexual maturation timing
  • Balanopreputial separation (males)
  • Eye opening, pinna unfolding, incisor eruption - general developmental markers
Functional Assessments of F1 Offspring
  • Neurobehavioral: motor activity, learning and memory (Morris water maze or passive avoidance), sensory function (acoustic startle response, visual placing)
  • Physical development: body weight, organ weights at necropsy
Reproductive Competence of F1 Generation
  • At least 1 male and 1 female per litter are selected and reared to adulthood
  • These F1 adults are then mated to assess their own fertility (this is what extends the study to sexual maturity)
  • Endpoints mirror Segment I: fertility index, litter size, implantation data
Histopathology of F1 (at weaning)
  • Brain, reproductive organs, liver, kidneys of selected pups

Key Indices in Segment III

IndexFormula
Live birth index(Live pups born / Total pups born) × 100
Viability index (Day 4)(Pups alive PND 4 / Pups born alive) × 100
Weaning index(Pups alive PND 21 / Pups alive PND 4) × 100
Sex ratio% males / % females at birth

Regulatory Context

  • Segment III (PPND) is generally required before Phase 3 trials and before marketing authorization
  • Under ICH M3(R2), PPND is not essential for Phase 2 trials but must be complete prior to marketing
  • For anticancer drugs targeting advanced cancer (ICH S9), PPND is generally not required to support marketing

Comparison: Segment I vs. Segment III

FeatureSegment I (FEED)Segment III (PPND)
Stages coveredA, BC through F
Dosing period (female)2 wks pre-mating to GD 6-7GD 6-7 to PND 21
Primary focusFertility, implantationParturition, postnatal development
Key female endpointsEstrous cycle, ovulation, implantationLabor, lactation, maternal behavior
Offspring assessmentLive implants only (no live birth)Full postnatal development, F1 fertility
SpeciesRodent (rat preferred)Rodent (rat preferred); NHP for biologics
Required beforePhase 2 (WOCBP)Phase 3 / Marketing
Duration~6-8 weeks~3-4 months

Why Both Studies Are Needed

Segment I detects toxicity to gametogenesis and early embryo survival, while Segment III covers a completely different window - it detects birth defects due to late gestational exposure, impaired delivery, lactation failure, and multigenerational effects on the F1 offspring. Neither study can substitute for the other because they target non-overlapping biological stages.
Together with Segment II (teratogenicity during organogenesis), these three segments provide a complete picture of a drug's reproductive safety profile across the entire reproductive cycle - from egg maturation through the sexual maturity of the next generation.
Regulatory References:
  • ICH S5(R3) - Detection of Reproductive and Developmental Toxicity for Human Pharmaceuticals
  • ICH M3(R2) - Nonclinical Safety Studies for Clinical Trials
  • ICH S9 - Anticancer Pharmaceuticals

Based on oecd guideline

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OECD guideline 415 416 Segment I fertility reproductive toxicity female detailed endpoints

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OECD guideline 426 Segment III pre postnatal developmental neurotoxicity female reproductive toxicity endpoints

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https://www.oecd.org/content/dam/oecd/en/publications/report…

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https://ntp.niehs.nih.gov/sites/default/files/iccvam/suppdoc…

I now have rich data from OECD TG 415, 416, 421, 422, and 426. Here is the complete, OECD-specific answer:

Segment I and Segment III Female Reproductive Toxicity Studies - Per OECD Guidelines

OECD Guideline Framework Overview

The OECD maps the traditional Segment classification to specific Test Guidelines (TGs):
SegmentNamePrimary OECD TGs
Segment IFertility & Early Embryonic DevelopmentTG 415 (One-Generation), TG 416 (Two-Generation), TG 421 (Screening), TG 422 (Combined), TG 443 (Extended One-Gen)
Segment IIPrenatal Developmental Toxicity (Teratology)TG 414
Segment IIIPre- and Postnatal DevelopmentTG 426 (Developmental Neurotoxicity), embedded in TG 416/443

SEGMENT I - Female Reproductive Toxicity

Applicable OECD Test Guidelines

1. OECD TG 415 - One-Generation Reproduction Toxicity Study

Purpose: To provide information on the effects of a substance on male and female reproductive performance over one generation.
Test Species: Rats (preferred); minimum 3 dose groups + control
Female Dosing Period:
  • Begins at least 2 weeks before mating (to cover at least 2 complete estrous cycles)
  • Continues through mating, gestation, and lactation until weaning
Female-Specific Endpoints:
Pre-mating Phase:
  • Estrous cyclicity - vaginal smears taken daily to characterize cycle length, phase duration, and regularity before and during treatment
  • Body weight and clinical signs monitored weekly
Mating Phase:
  • Pre-coital interval - days from pairing to confirmed mating (vaginal plug or sperm-positive smear)
  • Copulation index = (females mated / females paired) × 100
  • Fertility index = (pregnant females / females mated) × 100
Gestation:
  • Females weighed on GD 0, 7, 14, and 20/21
  • Food consumption measured weekly
  • Duration of gestation recorded
Parturition:
  • Ease and duration of delivery
  • Dystocia observations
  • Cannibalism rate
Lactation:
  • Maternal behavior and nursing
  • Litter care assessment
Terminal Assessment (Female Reproductive Organs):
  • Ovarian weight and histopathology
  • Corpora lutea count per ovary (number of eggs released)
  • Follicle counts (primordial, primary, secondary, antral) to detect follicular depletion
  • Uterine weight and gross appearance
  • Histopathology of: ovaries, uterus, cervix, vagina, oviducts, mammary glands
Implantation Data:
  • Total number of implantation sites
  • Number of live implants (live fetuses/resorptions)
  • Pre-implantation loss = (corpora lutea - implants) / corpora lutea × 100
  • Post-implantation loss = (implants - live fetuses) / implants × 100

2. OECD TG 416 - Two-Generation Reproduction Toxicity Study

Purpose: To evaluate reproductive integrity and performance in both P (parental) and F1 (first filial) generations, covering gonadal function, estrous cycle, mating behavior, conception, gestation, parturition, lactation, weaning, and offspring growth and sexual development.
Test Species: Rats (preferred); minimum 20 females per dose group
Two-Generation Design (Female-Specific):
P Generation (Parental Females):
  • Dosing begins 10 weeks before mating (to encompass full folliculogenesis cycle)
  • Continues throughout mating, gestation, and lactation of the F1 litter
  • Estrous cycles monitored via daily vaginal cytology during pre-mating, mating, and into gestation
  • Gestation weights: GD 0, 7, 14, 20/21
  • Lactation weights: same schedule as litter weighings
F1 Generation Females (Daughters) - the critical OECD TG 416 addition:
  • F1 pups are selected at weaning to become the F1 parents
  • F1 females are dosed from weaning (PND 21) through mating, gestation, and lactation of F2 litter
  • Vaginal opening (sexual maturation marker) is monitored daily from PND 25-30
  • First estrous cycle post-vaginal opening is recorded
  • Estrous cycle monitored for at least 2 weeks before F1 mating
  • F1 females are assessed for all the same endpoints as P females
Additional TG 416 Female Endpoints:
  • Anogenital distance (AGD) measured at birth and PND 4 - indicator of androgenic/estrogenic disruption
  • Number of nipples/areolae in male pups - indicator of anti-androgenic effects
  • Vaginal cytology of F1 females during adulthood
Reproductive Outcome Data Collected:
EndpointFormula
Gestation index(Females with live born pups / pregnant females) × 100
Live birth index(Pups born alive / total pups born) × 100
Viability index (PND 4)(Pups alive PND 4 / pups born alive) × 100
Lactation index (PND 21)(Pups alive PND 21 / pups alive PND 4) × 100
Sex ratio% male pups at birth

3. OECD TG 421 - Reproduction/Developmental Toxicity Screening Test

Purpose: Generates limited, preliminary information on reproductive toxicity. Not a replacement for TG 415/416/443.
Female Dosing:
  • 2 weeks before mating, through mating, gestation, and at least 13 days post-partum
Female-Specific Endpoints (Screening Level):
  • Estrous cycles: monitored from pre-dosing period to select females with regular cyclicity; vaginal smears daily from start of treatment to evidence of mating
  • Mating and fertility indices
  • Gestation weights (GD 0, 7, 14, 20; within 24 h of parturition; PND 0/1, 4, 13)
  • Food consumption weekly
  • Parturition observation: timing, duration, stillbirths
  • Pup viability on PND 4 and 13
  • Uterine examination at necropsy: number of implantation sites, corpora lutea
Key OECD TG 421 Pre-Natal/Post-Implantation Loss Table: The guideline specifically tabulates females by number of pre-natal losses and post-natal losses (0, 1, 2, ≥3) to identify dose-dependent patterns of reproductive failure.

4. OECD TG 422 - Combined Repeated Dose Toxicity Study with Reproduction/Developmental Toxicity Screening Test

Same female reproductive endpoints as TG 421, but combined with a 28-day repeated dose general toxicity study - used for chemicals with limited production volumes. This is a tiered screening tool, not a definitive reproductive study.

5. OECD TG 443 - Extended One-Generation Reproductive Toxicity Study (EOGRT)

The current recommended standard replacing TG 416 for many regulatory purposes.
Key additions over TG 416 for females:
  • Optional Cohort 2 (developmental neurotoxicity) and Cohort 3 (developmental immunotoxicity)
  • Ovarian primordial follicle quantification is mandatory
  • Thyroid hormones (T3, T4, TSH) in dams and F1 pups
  • Expanded developmental landmarks and functional endpoints

SEGMENT III - Female Reproductive Toxicity (Pre- and Postnatal Development)

Primary OECD Test Guideline: TG 426 - Developmental Neurotoxicity Study

(Also covered within TG 416 and TG 443 postnatal phases)

OECD TG 426 - Developmental Neurotoxicity (DNT) Study

Purpose: To detect adverse effects on the developing nervous system and the reproductive capacity of offspring following gestational and postnatal exposure through lactation. Specifically assesses:
  • General maternal toxicity during gestation and lactation
  • Offspring developmental and neurofunctional endpoints
  • Offspring reproductive competence (when F1 animals are evaluated through adulthood)
Test Species: Rat (preferred); minimum 20 litters per dose group (to ensure statistical power for neurotoxicity endpoints)
Female (Dam) Dosing Timeline (TG 426):
PeriodTimeframe
Start of dosingGestational Day 6 (GD 6)
Through gestationGD 6 to parturition (GD ~22)
Lactation phasePostnatal Day 0 (PND 0) to PND 21 (weaning)
Total dosing window~5 weeks
This window covers late organogenesis through brain development (the brain undergoes the "brain growth spurt" postnatally in rats, equivalent to the third trimester in humans).

Female (Dam) Endpoints in OECD TG 426

1. Maternal Toxicity Monitoring
  • Body weight: recorded at GD 0, 6, 9, 12, 15, 17, 20 and PND 1, 4, 7, 14, 21
  • Food consumption: weekly throughout gestation and lactation
  • Clinical signs: daily observation; onset, degree, duration of any toxic signs recorded individually
  • Comparison of toxicity in pregnant vs. non-pregnant state is mandatory - to detect whether the gravid/lactating female is more susceptible (enhanced toxicity)
2. Parturition Assessment
  • Gestation length (number of days from confirmed mating to delivery)
  • Parturition duration and ease - prolonged or difficult delivery noted
  • Number of pups born alive vs. stillborn
  • Post-partum observations for cannibalism or neglect
3. Litter Standardization (PND 4)
  • On or before PND 4, litter size is adjusted (culled) to the average litter size for the strain (typically 8-12 pups per litter), with equal sex ratio
  • This step normalizes nutritional availability through maternal milk - critical to prevent confounding
4. Lactation Behavior
  • Nursing posture, pup retrieval, nest building
  • Maternal milk sufficiency assessed indirectly through pup weight gain

Offspring (F1) Endpoints in OECD TG 426 - Sex-Specific Developmental Landmarks

Physical Development Landmarks (Pre-weaning):
LandmarkSexApproximate Timing
Pinna unfoldingBothPND 3-5
Incisor eruptionBothPND 7-10
Eye openingBothPND 12-15
Vaginal openingFemalePND 28-35 (index of pubertal timing)
Balanopreputial separationMalePND 40-50
Note: OECD TG 426 states that pre-weaning landmarks are highly correlated with body weight, so body weight may be the best indicator of physical development. Developmental landmarks are recommended only when prior evidence suggests they provide additional information beyond body weight.
Neurobehavioral Functional Battery (F1 Offspring):
  • Motor activity: measured using automated activity monitors; assessed at approximately PND 21, 40-45, and 60-70; should show habituation (decrease in activity within session)
  • Acoustic startle response: assessed at approximately PND 22-24 and post-weaning; includes prepulse inhibition
  • Cognitive function: learning and memory tests (passive avoidance or Morris water maze) at approximately PND 60-75
  • Sensory function: visual and auditory assessments
Neuropathology (F1 Offspring):
  • Perfusion-fixed brains at PND 11 (neonatal) and PND 70+ (adult)
  • Brain weight and morphometric analysis
  • Brain regions examined histologically: cerebral cortex, hippocampus, cerebellum, striatum, brainstem, olfactory bulb
  • Morphometric measurements: cortical thickness, hippocampal areas, cerebellar volume

Segment III Endpoints Embedded within OECD TG 416 (Two-Generation Study)

TG 416 also contains full Segment III-level assessment as part of the F1 litter postnatal phase:
Post-natal offspring monitoring:
  • Live birth index, viability index, lactation index (formulae listed above)
  • Pup weights on PND 1, 4, 7, 14, 21
  • Anogenital distance (AGD) at PND 1 and 4 (sex-specific index of endocrine disruption)
  • Number of nipple/areolae anlagen in male pups
  • Sex ratio at birth and on PND 4
  • Developmental landmarks: vaginal opening (females), testis descent and balanopreputial separation (males)
F1 sexual development and reproductive competence:
  • Vaginal opening monitored daily from PND 25-30
  • First estrous cycle after vaginal opening recorded
  • F1 females mated to produce F2 litter - all parturition/litter data collected again (confirms the next generation's fertility)

Summary Comparison Table: OECD-Based Segment I vs. Segment III

FeatureSegment ISegment III
Primary OECD TGsTG 415, 416, 421, 422, 443TG 426; also within TG 416/443
Dosing onset (female)2-10 weeks pre-matingGD 6 (post-implantation)
Dosing endGD 6-7 (implantation) or Cesarean sectionPND 21 (weaning)
Key female endpointsEstrous cycle, ovulation, corpora lutea, implantation, fertility indexGestation length, parturition ease, lactation, maternal behavior
Ovarian histopathologyYes - follicle counts, CL count (mandatory in TG 443)Not primary focus (TG 426 focuses on pup neurodevelopment)
Offspring assessedImplantation sites only (no live birth in Segment I proper)Full postnatal: body weight, landmarks, neurobehavior, brain morphometry
Pup endpointsNone (Cesarean section at GD 13-21)Motor activity, startle response, learning/memory, neuropathology
F1 reproductive competenceN/A for Segment I aloneYes in TG 416/443 - F1 females mated for F2 data
Group size (female)≥20 females mated per group≥20 litters evaluable per group
SpeciesRat (primarily)Rat (TG 426); NHP for biologics

Regulatory Notes (OECD Context)

  • TG 415 is the older (1983) one-generation design and is being phased out in favor of TG 443
  • TG 416 (two-generation) is still widely used but TG 443 is now the preferred choice under OECD because it reduces animal use while providing richer data (neurotoxicity, immunotoxicity cohorts)
  • TG 421/422 are screening tests only - they cannot substitute for TG 414, 415, 416, or 443 for regulatory submissions
  • OECD guidelines align closely with ICH S5(R3) for pharmaceuticals, but OECD TGs also apply to industrial chemicals, pesticides, and food additives under REACH, CLP, and biocidal product regulations

Create a comparison poster of OECD TG 415 vs TG 416 vs TG 443 study designs

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A detailed scientific comparison poster titled "OECD Reproductive Toxicity Study Designs: TG 415 vs TG 416 vs TG 443" with a clean, professional medical/regulatory style on a white background. The poster has three main columns, one for each guideline, with a distinct color header: TG 415 (One-Generation) in teal/green, TG 416 (Two-Generation) in deep blue, TG 443 (Extended One-Generation / EOGRT) in purple. Each column contains clearly labeled sections: ROW 1 - HEADER BANNERS: - TG 415: "One-Generation Reproduction Toxicity Study" | Adopted: 1983 - TG 416: "Two-Generation Reproduction Toxicity Study" | Adopted: 2001 - TG 443: "Extended One-Generation Reproductive Toxicity Study (EOGRT)" | Adopted: 2011 ROW 2 - PURPOSE (small icons): - TG 415: Effects on male & female reproductive performance; single generation - TG 416: Integrity of reproductive systems across two generations (P, F1, F2) - TG 443: Comprehensive one-generation with optional neurotoxicity & immunotoxicity cohorts; preferred current standard ROW 3 - SPECIES & GROUP SIZE: - TG 415: Rat preferred | 20 females/group - TG 416: Rat preferred | 20 females/group (P and F1) - TG 443: Rat preferred | 20 females/group ROW 4 - FEMALE DOSING TIMELINE (small horizontal timeline bars): - TG 415: 2 weeks pre-mating → mating → gestation → lactation (PND 21) - TG 416: 10 weeks pre-mating (P females) → mating → GD 0–21 → lactation PND 21; F1 females dosed from weaning → mating → GD 0–21 → PND 21 - TG 443: 2 weeks pre-mating → mating → GD 0 → PND 21 (weaning); Cohort 1A continues to adulthood ROW 5 - KEY FEMALE ENDPOINTS: TG 415: • Estrous cyclicity (vaginal smears) • Copulation & fertility index • Gestation length • Parturition observations • Corpora lutea count • Implantation sites • Pre/post-implantation loss • Ovarian histopathology • Uterine histopathology TG 416: • All TG 415 endpoints PLUS: • Vaginal opening (F1 females, PND 25–30) • First estrous cycle post-vaginal opening • Anogenital distance (PND 1 & 4) • Nipple/areolae in male pups • F1 female fertility & F2 litter data • Organ weights (ovary, uterus) TG 443: • All TG 416 endpoints PLUS: • Primordial follicle quantification (MANDATORY) • Thyroid hormones (T3, T4, TSH) in dams & F1 • Cohort 1A: F1 fertility (mandatory) • Cohort 2A/2B: Developmental neurotoxicity (optional trigger) • Cohort 3: Developmental immunotoxicity (optional trigger) ROW 6 - GENERATIONS ASSESSED: - TG 415: P + F1 litter (no F1 adults mated) - TG 416: P + F1 adults mated → F2 litter - TG 443: P + F1 Cohort 1A (mated) → limited F2; Cohorts 2 & 3 for specialized endpoints ROW 7 - OFFSPRING ENDPOINTS: - TG 415: Live birth index, viability index, pup weights PND 1–21, sex ratio - TG 416: All TG 415 PLUS sexual maturation landmarks, F1 organ weights, F2 litter data - TG 443: All TG 416 PLUS motor activity, acoustic startle, learning & memory, brain weight & morphometry, immune function panels ROW 8 - STATUS / REGULATORY USE: - TG 415: OUTDATED — being phased out; limited current use - TG 416: Still accepted; used for pesticides/industrial chemicals under REACH - TG 443: PREFERRED CURRENT STANDARD under OECD/REACH; reduces animal use vs TG 416 ROW 9 - ADVANTAGES VS LIMITATIONS (color-coded green/red bullet points): TG 415: + Simple, shorter | − Only one generation; no F1 adult data; no follicle count TG 416: + Two generations; F1 reproductive competence | − High animal use; no neurotoxicity TG 443: + Comprehensive; built-in neurotox & immunotox cohorts; follicle count mandatory | − Complex design; higher cost At the bottom, a footer bar: "Reference: OECD Guidelines for Testing of Chemicals | TG 415 (1983), TG 416 (2001), TG 443 (2011)" The overall layout is a well-organized scientific poster, easy to read, with color-coded columns, horizontal comparison rows, small timeline diagrams, and bullet-point lists. Bold section labels. Clean white background with subtle grid lines separating rows.

OECD TG 415 vs TG 416 vs TG 443 Comparison Poster
Here is your comparison poster covering all three OECD reproductive toxicity study designs. Here is a quick read of what it captures:
TG 415 (Teal - One-Generation, 1983)
  • The oldest and simplest design; females dosed 2 weeks pre-mating through lactation
  • Only one generation assessed; no F1 adult mating
  • Being phased out - limited current regulatory acceptance
TG 416 (Blue - Two-Generation, 2001)
  • Adds a full F1 generation of adult females dosed from weaning, mated to produce an F2 litter
  • Captures vaginal opening, first estrous cycle, and F1 female fertility
  • Still widely used under REACH for industrial chemicals and pesticides
TG 443 (Purple - EOGRT, 2011)
  • The current preferred OECD standard - replaces TG 416 for most purposes
  • Mandatory primordial follicle quantification and thyroid hormones in dams/F1
  • Modular cohort system: Cohort 2 (neurotoxicity) and Cohort 3 (immunotoxicity) can be triggered
  • Reduces total animal use vs TG 416 while providing deeper mechanistic data
The key regulatory message is: TG 443 > TG 416 > TG 415 in terms of comprehensiveness, and TG 443 is now the standard required by OECD/REACH for new submissions.

Create a detailed timeline diagram showing dosing windows for each TG

Running Command

ls -la /home/daytona/workspace/ 2>/dev/null || mkdir -p /home/daytona/workspace && echo "workspace ready"

Running Command

mkdir -p /home/daytona/workspace/oecd-timeline && python3 << 'EOF' import matplotlib matplotlib.use('Agg') import matplotlib.pyplot as plt import matplotlib.patches as mpatches from matplotlib.patches import FancyArrowPatch, FancyBboxPatch import matplotlib.patheffects as pe import numpy as np # ── colour palette ────────────────────────────────────────────────────────── C = { 'bg': '#F8F9FC', 'grid': '#E2E6ED', 'teal': '#00897B', 'teal_lt': '#B2DFDB', 'blue': '#1565C0', 'blue_lt': '#BBDEFB', 'purple': '#6A1B9A', 'purple_lt': '#E1BEE7', # phase colours 'premating': '#FF8F00', 'mating': '#F57F17', 'gestation': '#2E7D32', 'lactation': '#1565C0', 'weaning': '#6A1B9A', 'adult': '#AD1457', 'cohort2': '#00838F', 'cohort3': '#558B2F', 'f2': '#E65100', 'necropsy': '#B71C1C', 'white': '#FFFFFF', 'dark': '#1A1A2E', 'subtext': '#4A4A6A', } # ── figure ─────────────────────────────────────────────────────────────────── fig = plt.figure(figsize=(24, 20), facecolor=C['bg']) ax = fig.add_axes([0, 0, 1, 1]) ax.set_xlim(0, 1) ax.set_ylim(0, 1) ax.axis('off') ax.set_facecolor(C['bg']) # ── helpers ─────────────────────────────────────────────────────────────────── def bar(ax, x0, x1, y, h, color, alpha=1.0, radius=0.008, label=None, fontsize=8.5, zorder=3): """Draw a rounded rectangle bar.""" width = x1 - x0 rect = FancyBboxPatch((x0, y - h/2), width, h, boxstyle=f"round,pad=0,rounding_size={radius}", linewidth=0, facecolor=color, alpha=alpha, zorder=zorder) ax.add_patch(rect) if label: mid = (x0 + x1) / 2 ax.text(mid, y, label, ha='center', va='center', fontsize=fontsize, fontweight='bold', color=C['white'], zorder=zorder+1, path_effects=[pe.withStroke(linewidth=1.5, foreground='#00000040')]) def vline(ax, x, y0, y1, color='#888', lw=1, ls='--', zorder=2): ax.plot([x, x], [y0, y1], color=color, linewidth=lw, linestyle=ls, zorder=zorder) def tick_label(ax, x, y, label, fontsize=8, color='#555', ha='center'): ax.text(x, y, label, ha=ha, va='top', fontsize=fontsize, color=color, fontfamily='monospace') def section_header(ax, x, y, w, h, label, color, sub=''): rect = FancyBboxPatch((x, y), w, h, boxstyle="round,pad=0,rounding_size=0.006", linewidth=0, facecolor=color, zorder=4) ax.add_patch(rect) ax.text(x + w/2, y + h*0.62, label, ha='center', va='center', fontsize=14, fontweight='bold', color=C['white'], zorder=5) if sub: ax.text(x + w/2, y + h*0.22, sub, ha='center', va='center', fontsize=9.5, color='#FFFFFFCC', zorder=5) def row_bg(ax, y_center, height, color='#FFFFFF80', zorder=1): rect = FancyBboxPatch((0.01, y_center - height/2), 0.98, height, boxstyle="round,pad=0,rounding_size=0.004", linewidth=0.5, edgecolor='#D0D4DD', facecolor=color, zorder=zorder) ax.add_patch(rect) def annotation(ax, x, y, text, color, fontsize=7.5): ax.text(x, y, text, ha='center', va='bottom', fontsize=fontsize, color=color, fontweight='bold', rotation=0) def side_label(ax, x, y, text, color, fontsize=10): ax.text(x, y, text, ha='right', va='center', fontsize=fontsize, color=color, fontweight='bold') # ── TITLE ───────────────────────────────────────────────────────────────────── ax.text(0.5, 0.975, 'OECD Reproductive Toxicity Test Guidelines', ha='center', va='top', fontsize=22, fontweight='bold', color=C['dark']) ax.text(0.5, 0.953, 'Dosing Windows & Study Timeline Comparison · TG 415 | TG 416 | TG 443 (EOGRT)', ha='center', va='top', fontsize=13, color=C['subtext']) # thin separator line ax.plot([0.03, 0.97], [0.942, 0.942], color='#C0C8D8', linewidth=1.5) # ── LEGEND ──────────────────────────────────────────────────────────────────── legend_y = 0.928 legend_items = [ ('Pre-mating dosing', C['premating']), ('Mating period', C['mating']), ('Gestation (GD 0–21)', C['gestation']), ('Lactation (PND 0–21)',C['lactation']), ('Post-weaning / Adult',C['adult']), ('F2 Litter phase', C['f2']), ('Cohort 2 – Neuro', C['cohort2']), ('Cohort 3 – Immuno', C['cohort3']), ('Necropsy ✚', C['necropsy']), ] lx = 0.04 for label, col in legend_items: rect = FancyBboxPatch((lx, legend_y - 0.010), 0.022, 0.016, boxstyle="round,pad=0,rounding_size=0.003", linewidth=0, facecolor=col, zorder=5) ax.add_patch(rect) ax.text(lx + 0.025, legend_y - 0.002, label, va='center', fontsize=8, color=C['dark']) lx += 0.107 # ── TIMELINE X-AXIS SETUP ──────────────────────────────────────────────────── # We map study days onto a common relative axis # Origin = Start of Pre-mating dosing (Day 0 of study) # All three TGs aligned at GD 0 (conception) for visual clarity # Key day markers (relative to start of pre-mating dosing): # TG 415: Day 0=pre-mating start; Day 14=GD0; Day 35=GD21(birth); Day 56=PND21(wean/necropsy) # TG 416: Day 0=P pre-mating; Day 70=P GD0; Day 91=P GD21; Day 112=F1PND21(wean) # F1 females then dosed from Day 112; F1 mating ~Day 182; F1 GD0 ~Day 182 # F1 GD21 ~Day 203; F2 PND21 ~Day 224 (necropsy) # TG 443: Day 0=pre-mating; Day 14=GD0; Day 35=GD21; Day 56=PND21 # Cohort 1A continues to ~Day 126 (adult mating) # Cohort 2 continues to ~Day 140 (neurotox done) # Cohort 3 continues to ~Day 140 (immunotox done) # Global x range covers 0..240 days DAY_MIN = -14 # 2 weeks before pre-mating for context DAY_MAX = 240 def d2x(day): """Convert study day to axes x coordinate (0.09 to 0.97).""" return 0.09 + (day - DAY_MIN) / (DAY_MAX - DAY_MIN) * 0.88 # ── X-AXIS (shared timeline) ────────────────────────────────────────────────── AXIS_Y = 0.082 ax.annotate('', xy=(d2x(DAY_MAX)+0.005, AXIS_Y), xytext=(d2x(DAY_MIN)-0.005, AXIS_Y), arrowprops=dict(arrowstyle='->', color=C['dark'], lw=2), zorder=6) # day tick marks at key milestones tick_days = { -14: '-14', 0: '0\n(Pre-mating\nstart)', 14: 'GD 0\n(±14)', 35: 'GD 21\n(Birth)', 56: 'PND 21\n(Wean)', 70: 'Day 70\n(P GD 0\nTG416)', 91: 'Day 91\n(P Birth\nTG416)', 112: 'Day 112\n(F1 Wean\nTG416)', 126: 'Day 126\n(F1 Adult)', 182: 'Day 182\n(F1 GD 0\nTG416)', 203: 'Day 203\n(F2 Birth)', 224: 'Day 224\n(F2 Wean\nNecropsy)', } for day, lbl in tick_days.items(): tx = d2x(day) ax.plot([tx, tx], [AXIS_Y - 0.008, AXIS_Y + 0.008], color=C['dark'], lw=1.2, zorder=6) ax.text(tx, AXIS_Y - 0.012, lbl, ha='center', va='top', fontsize=6.5, color=C['subtext'], linespacing=1.3) ax.text(d2x(DAY_MAX)+0.012, AXIS_Y, 'Study Days', ha='left', va='center', fontsize=9, color=C['dark'], fontweight='bold') # ── SECTION HEADERS (TG labels on left) ────────────────────────────────────── # Row Y centers (from top) Y_TG415_H = 0.86 # TG 415 section header top Y_TG415_P = 0.80 # TG 415 P-generation row Y_TG415_F1 = 0.74 # TG 415 F1 litter row Y_TG416_H = 0.64 Y_TG416_P = 0.58 Y_TG416_F1 = 0.52 Y_TG416_F2 = 0.46 Y_TG443_H = 0.36 Y_TG443_P = 0.30 Y_TG443_C1A = 0.24 Y_TG443_C2 = 0.18 Y_TG443_C3 = 0.12 BAR_H = 0.030 HEADER_H = 0.030 # ── row backgrounds ─────────────────────────────────────────────────────────── for yc in [Y_TG415_P, Y_TG415_F1, Y_TG416_P, Y_TG416_F1, Y_TG416_F2, Y_TG443_P, Y_TG443_C1A, Y_TG443_C2, Y_TG443_C3]: row_bg(ax, yc, BAR_H + 0.018) # ── TG 415 SECTION ─────────────────────────────────────────────────────────── section_header(ax, 0.01, Y_TG415_H - 0.002, 0.07, HEADER_H + 0.008, 'OECD TG 415', C['teal'], 'One-Generation (1983)') ax.plot([0.01, 0.97], [Y_TG415_H - 0.004, Y_TG415_H - 0.004], color=C['teal'], linewidth=1.0, alpha=0.4) # P generation row label side_label(ax, 0.085, Y_TG415_P, 'P ♀ (Parent)', C['teal'], 10) # Pre-mating: Day 0–14 bar(ax, d2x(0), d2x(14), Y_TG415_P, BAR_H, C['premating'], label='Pre-mating\n14 days') annotation(ax, d2x(7), Y_TG415_P + BAR_H/2 + 0.008, '2 oestrous cycles', C['premating']) # Mating: Day 14–19 bar(ax, d2x(14), d2x(19), Y_TG415_P, BAR_H, C['mating'], label='Mat.') # Gestation: Day 19–40 (GD 0–21) bar(ax, d2x(19), d2x(40), Y_TG415_P, BAR_H, C['gestation'], label='Gestation\nGD 0–21') # Lactation: Day 40–61 (PND 0–21) bar(ax, d2x(40), d2x(61), Y_TG415_P, BAR_H, C['lactation'], label='Lactation\nPND 0–21') # Necropsy marker vline(ax, d2x(61), Y_TG415_P - BAR_H/2 - 0.005, Y_TG415_P + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(61), Y_TG415_P + BAR_H/2 + 0.008, '✚ Necropsy PND 21', C['necropsy']) # F1 litter row side_label(ax, 0.085, Y_TG415_F1, 'F1 Litter', C['teal'], 10) bar(ax, d2x(40), d2x(61), Y_TG415_F1, BAR_H, C['lactation'], alpha=0.55, label='F1 Pups\nPND 0–21') annotation(ax, d2x(50), Y_TG415_F1 - BAR_H/2 - 0.012, 'Live birth index · Viability index · Pup weights · Sex ratio', C['subtext'], fontsize=7.5) # Necropsy marker F1 vline(ax, d2x(61), Y_TG415_F1 - BAR_H/2 - 0.005, Y_TG415_F1 + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') # Status badge rect = FancyBboxPatch((d2x(70), Y_TG415_H - 0.016), 0.13, 0.022, boxstyle="round,pad=0,rounding_size=0.004", linewidth=0, facecolor='#FF6F00', zorder=6) ax.add_patch(rect) ax.text(d2x(70) + 0.065, Y_TG415_H - 0.006, '⚠ OUTDATED — limited current regulatory use', ha='center', va='center', fontsize=8.5, color=C['white'], fontweight='bold', zorder=7) # ── TG 416 SECTION ─────────────────────────────────────────────────────────── section_header(ax, 0.01, Y_TG416_H - 0.002, 0.07, HEADER_H + 0.008, 'OECD TG 416', C['blue'], 'Two-Generation (2001)') ax.plot([0.01, 0.97], [Y_TG416_H - 0.004, Y_TG416_H - 0.004], color=C['blue'], linewidth=1.0, alpha=0.4) # P generation side_label(ax, 0.085, Y_TG416_P, 'P ♀ (Parental)', C['blue'], 10) # Pre-mating: 10 weeks = 70 days bar(ax, d2x(0), d2x(70), Y_TG416_P, BAR_H, C['premating'], label='Pre-mating 70 days (10 wks)') annotation(ax, d2x(35), Y_TG416_P + BAR_H/2 + 0.008, 'folliculogenesis + spermatogenesis cycle', C['premating']) bar(ax, d2x(70), d2x(75), Y_TG416_P, BAR_H, C['mating'], label='Mat.') bar(ax, d2x(75), d2x(96), Y_TG416_P, BAR_H, C['gestation'], label='Gestation GD 0–21') bar(ax, d2x(96), d2x(117), Y_TG416_P, BAR_H, C['lactation'], label='Lactation PND 0–21') vline(ax, d2x(117), Y_TG416_P - BAR_H/2, Y_TG416_P + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(117), Y_TG416_P + BAR_H/2 + 0.008, '✚ P Necropsy', C['necropsy']) # F1 females side_label(ax, 0.085, Y_TG416_F1, 'F1 ♀ (Daughters)', C['blue'], 10) # F1 dosed from weaning (Day 117) pre-mating 14 days; mating Day 131; GD0 Day 136; Birth Day 157; Wean/necropsy Day 178 bar(ax, d2x(117), d2x(131), Y_TG416_F1, BAR_H, C['premating'], label='Pre-mating 14d') annotation(ax, d2x(117), Y_TG416_F1 + BAR_H/2 + 0.008, 'Vaginal opening monitored\nfrom PND 25–30', C['premating'], 7.5) bar(ax, d2x(131), d2x(136), Y_TG416_F1, BAR_H, C['mating'], label='Mat.') bar(ax, d2x(136), d2x(157), Y_TG416_F1, BAR_H, C['gestation'], label='Gestation GD 0–21') bar(ax, d2x(157), d2x(178), Y_TG416_F1, BAR_H, C['lactation'], label='Lactation PND 0–21') vline(ax, d2x(178), Y_TG416_F1 - BAR_H/2, Y_TG416_F1 + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(178), Y_TG416_F1 + BAR_H/2 + 0.008, '✚ F1 Necropsy', C['necropsy']) # F2 litter side_label(ax, 0.085, Y_TG416_F2, 'F2 Litter', C['blue'], 10) bar(ax, d2x(157), d2x(178), Y_TG416_F2, BAR_H, C['f2'], alpha=0.75, label='F2 Pups PND 0–21') annotation(ax, d2x(167), Y_TG416_F2 - BAR_H/2 - 0.012, 'Live birth · viability · pup weights · sex ratio · organ weights · AGD', C['subtext'], 7.5) vline(ax, d2x(178), Y_TG416_F2 - BAR_H/2, Y_TG416_F2 + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') # Status badge TG 416 rect2 = FancyBboxPatch((d2x(185), Y_TG416_H - 0.016), 0.14, 0.022, boxstyle="round,pad=0,rounding_size=0.004", linewidth=0, facecolor=C['blue'], zorder=6) ax.add_patch(rect2) ax.text(d2x(185) + 0.070, Y_TG416_H - 0.006, '✔ Still accepted | REACH / pesticides / industrial chemicals', ha='center', va='center', fontsize=8.5, color=C['white'], fontweight='bold', zorder=7) # ── TG 443 SECTION ─────────────────────────────────────────────────────────── section_header(ax, 0.01, Y_TG443_H - 0.002, 0.07, HEADER_H + 0.008, 'OECD TG 443', C['purple'], 'EOGRT — Extended One-Gen (2011)') ax.plot([0.01, 0.97], [Y_TG443_H - 0.004, Y_TG443_H - 0.004], color=C['purple'], linewidth=1.0, alpha=0.4) # P generation side_label(ax, 0.085, Y_TG443_P, 'P ♀ (Parental)', C['purple'], 10) bar(ax, d2x(0), d2x(14), Y_TG443_P, BAR_H, C['premating'], label='Pre-mating 14d') annotation(ax, d2x(7), Y_TG443_P + BAR_H/2 + 0.008, '≥2 oestrous cycles · follicle count · T3/T4/TSH', C['premating']) bar(ax, d2x(14), d2x(19), Y_TG443_P, BAR_H, C['mating'], label='Mat.') bar(ax, d2x(19), d2x(40), Y_TG443_P, BAR_H, C['gestation'], label='Gestation GD 0–21') bar(ax, d2x(40), d2x(61), Y_TG443_P, BAR_H, C['lactation'], label='Lactation PND 0–21') vline(ax, d2x(61), Y_TG443_P - BAR_H/2, Y_TG443_P + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(61), Y_TG443_P + BAR_H/2 + 0.008, '✚ P Necropsy\nPrimordial follicle count (MANDATORY)', C['necropsy'], 7) # Cohort 1A side_label(ax, 0.085, Y_TG443_C1A, 'Cohort 1A ♀\n(F1 Fertility)', C['purple'], 9) bar(ax, d2x(61), d2x(75), Y_TG443_C1A, BAR_H, C['adult'], label='Post-wean growth') annotation(ax, d2x(61), Y_TG443_C1A + BAR_H/2 + 0.008, 'Vaginal opening · 1st estrous · AGD monitored', C['adult']) bar(ax, d2x(75), d2x(110), Y_TG443_C1A, BAR_H, C['adult'], alpha=0.7, label='Adult pre-mating (≥10 wks)') bar(ax, d2x(110), d2x(115), Y_TG443_C1A, BAR_H, C['mating'], label='Mat.') bar(ax, d2x(115), d2x(136), Y_TG443_C1A, BAR_H, C['gestation'], label='GD 0–21') bar(ax, d2x(136), d2x(157), Y_TG443_C1A, BAR_H, C['f2'], label='F2 Litter PND 0–21') vline(ax, d2x(157), Y_TG443_C1A - BAR_H/2, Y_TG443_C1A + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(157), Y_TG443_C1A + BAR_H/2 + 0.008, '✚ Necropsy', C['necropsy']) # Cohort 2 (Developmental Neurotoxicity — triggered) side_label(ax, 0.085, Y_TG443_C2, 'Cohort 2\n(DNT — if triggered)', C['cohort2'], 9) bar(ax, d2x(40), d2x(61), Y_TG443_C2, BAR_H, C['lactation'], alpha=0.5, label='PND 0–21') bar(ax, d2x(61), d2x(140), Y_TG443_C2, BAR_H, C['cohort2'], alpha=0.85, label='Neurobehavioral endpoints PND 21 → PND ~77') annotation(ax, d2x(100), Y_TG443_C2 + BAR_H/2 + 0.008, 'Motor activity · Acoustic startle · Learning & memory · Brain morphometry', C['cohort2']) vline(ax, d2x(140), Y_TG443_C2 - BAR_H/2, Y_TG443_C2 + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(140), Y_TG443_C2 + BAR_H/2 + 0.008, '✚', C['necropsy']) # Cohort 3 (Developmental Immunotoxicity — triggered) side_label(ax, 0.085, Y_TG443_C3, 'Cohort 3\n(DIT — if triggered)', C['cohort3'], 9) bar(ax, d2x(40), d2x(61), Y_TG443_C3, BAR_H, C['lactation'], alpha=0.5, label='PND 0–21') bar(ax, d2x(61), d2x(126), Y_TG443_C3, BAR_H, C['cohort3'], alpha=0.85, label='Immunological assessments PND 21 → PND ~56') annotation(ax, d2x(90), Y_TG443_C3 - BAR_H/2 - 0.012, 'Lymphocyte subsets · NK cell activity · T-cell dependent antibody response', C['subtext'], 7.5) vline(ax, d2x(126), Y_TG443_C3 - BAR_H/2, Y_TG443_C3 + BAR_H/2 + 0.005, C['necropsy'], lw=2.5, ls='-') annotation(ax, d2x(126), Y_TG443_C3 + BAR_H/2 + 0.008, '✚', C['necropsy']) # Status badge TG 443 rect3 = FancyBboxPatch((d2x(165), Y_TG443_H - 0.016), 0.165, 0.022, boxstyle="round,pad=0,rounding_size=0.004", linewidth=0, facecolor=C['purple'], zorder=6) ax.add_patch(rect3) ax.text(d2x(165) + 0.083, Y_TG443_H - 0.006, '★ PREFERRED CURRENT STANDARD | OECD / REACH / Regulatory default', ha='center', va='center', fontsize=8.5, color=C['white'], fontweight='bold', zorder=7) # ── vertical milestone lines across entire chart ────────────────────────────── milestones = [ (d2x(0), 'Day 0\nPre-mating\nbegins', '#FF8F00'), (d2x(14), 'GD 0\n(≈Day 14)', '#2E7D32'), (d2x(35), 'GD 21\nBirth', '#2E7D32'), (d2x(61), 'PND 21\nWeaning', '#1565C0'), ] for mx, mlabel, mcol in milestones: ax.plot([mx, mx], [0.095, Y_TG415_H - 0.01], color=mcol, linewidth=1.2, linestyle=':', alpha=0.5, zorder=1) # ── bottom footer ───────────────────────────────────────────────────────────── ax.plot([0.03, 0.97], [0.068, 0.068], color='#C0C8D8', linewidth=1.2) ax.text(0.5, 0.058, 'GD = Gestational Day · PND = Postnatal Day · Mat. = Mating · AGD = Anogenital Distance · DNT = Developmental Neurotoxicity · DIT = Developmental Immunotoxicity', ha='center', va='center', fontsize=8, color=C['subtext']) ax.text(0.5, 0.044, 'Reference: OECD Guidelines for Testing of Chemicals | TG 415 (1983) · TG 416 (2001) · TG 443 (2011) · Bars represent FEMALE dosing windows', ha='center', va='center', fontsize=8, color=C['subtext']) # outer border border = FancyBboxPatch((0.005, 0.005), 0.990, 0.990, boxstyle="round,pad=0,rounding_size=0.01", linewidth=2, edgecolor='#B0BAD0', facecolor='none', zorder=10) ax.add_patch(border) # ── save ────────────────────────────────────────────────────────────────────── out = '/home/daytona/workspace/oecd-timeline/OECD_TG_Timeline_Diagram.png' fig.savefig(out, dpi=180, bbox_inches='tight', facecolor=C['bg']) plt.close() print(f"Saved: {out}") EOF

Reading File
Running Command

ls -lh /home/daytona/workspace/oecd-timeline/OECD_TG_Timeline_Diagram.png

Your timeline diagram is ready (702 KB, 180 DPI):

OECD TG Timeline Diagram

Image · PNG

Here is what the diagram contains:

TG 415 (Teal - top section)

  • P female row: Orange pre-mating bar (14 days, 2 estrous cycles) → mating → green gestation (GD 0-21) → blue lactation (PND 0-21) → red necropsy marker
  • F1 litter row: Shows pup monitoring PND 0-21; annotated with live birth index, viability index, pup weights, sex ratio
  • Status badge: ⚠ OUTDATED - limited current regulatory use

TG 416 (Blue - middle section)

  • P female row: 70-day pre-mating bar (10 weeks for full folliculogenesis) → mating → gestation → lactation → necropsy
  • F1 daughters row: Dosed from weaning (Day 117) → pre-mating with vaginal opening monitoring → mating → gestation → lactation → necropsy
  • F2 litter row: PND 0-21 with AGD, organ weights annotated
  • Status badge: ✔ Still accepted - REACH / pesticides / industrial chemicals

TG 443 EOGRT (Purple - bottom section)

  • P female row: Pre-mating with mandatory primordial follicle count + T3/T4/TSH annotation → gestation → lactation → necropsy
  • Cohort 1A (F1 fertility): Post-wean growth → adult pre-mating → mating → gestation → F2 litter → necropsy
  • Cohort 2 (DNT - triggered): Extends from PND 21 to ~Day 140 with motor activity, startle, learning/memory, brain morphometry
  • Cohort 3 (DIT - triggered): Extends to ~Day 126 with lymphocyte subsets, NK cell activity, T-cell antibody response
  • Status badge: ★ PREFERRED CURRENT STANDARD
A shared day-scale x-axis runs across all three sections with labeled milestone markers (GD 0, GD 21/Birth, PND 21/Weaning) and dashed vertical reference lines for alignment.
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