Regulatory Toxicology Tests Flashcards
(20 cards)
hERG Binding Assay
In vitro cardiotoxicity test.
Radioligand binding assay, bind strongly to hERG channel, if compound displaces it is toxic.
hERG Patch Clamp Assay
In vitro, cardiotoxicity test.
Electrophysiological recordings of K+ current through hERG channel in presence of drug.
Cardiotoxicity Tests
Radioligand binding assay
hERG Patch clamp assay
Phototoxicity Test
In vitro, neutral red up take assay.
Neutral Red Uptake Assay
Use mouse fibroblast cell line 3T3.
Cytotoxicity if conc. dependent reduction of uptake of neutral red dye measured 24hrs after exposure to chemical and irradiation (UV)
Cytotoxicity tested in presence of UV and without UV.
Skin Sensitisation Testing
In vivo, local lymph node assay.
Test lymph node cell proliferation.
Acute Toxicity
In vivo, done as part of other tests (e.g. repeat dose study), small number of rodents, clinical route only.
(body weight loss end point)
Repeat Dose Toxicity
In vivo, subacute 28 days
subchronic 90 days.
Rodents and non-rodents. 3-4 dose levels. Lower dose than acute.
Duration of repeat dose studies
For clinical trials have to be at least as long as study duration.
For marketing the repeat dose studies have to be longer e.g 3 months of treatment needs 6 month study.
Knowing this lots of companies will continue studies longer.
Long term carcinogenicity testing
In vivo
Rat-24 months
Mouse-18months min 500 animals.
Needed when drug is going to be continuously used for 6 months.
or recurrent use in intermittent manner e.g. anxiety.
If drug is genotoxic will be carciogenic in some cases still moves forward if can prolong life in end of life treatment, old ppl.
Positive Carcinogenic Testing
-Increase in frequency of 1 or several tumours that occur in control.
-new tumours,
-earlier appearance of tumours
-more tumors in one animal
Stages of Reproductive Toxicity Testing
A) Premating to conception
B) Conception to implantation
C) Implantation to closure of hard palate (organogenesis)
D) Closure of hard palate to end of pregnancy
E) Birth to weaning.
F) Weaning to sexual maturity
Reproductive Toxicity Tests (in vivo)
FEED - Fertility and early embryonic development to implantation [FEED]
PPND - Effects on pre and post natal development
EFD- Effects on embryo foetal development
FEED - Fertility and early embryonic development
Rats,
Covers premating to implantation.
Gamete production and release, mating behaviours, implantation and embryo viability.
Potential Parameter = pre coital intervals
PPND - Pre and Post Natal Development
Rats.
Covers implantation to weaning.
Male and female reared to sexual maturity and mated (looking at f1 fertility).
Parameters= development issues of offspring, behaviour issues, mother weight gain, effect on reproduction
EFD- Embryo foetal development
Rats and Rabbits.
Effects on pregnant female and embryo development.
Caesarian carried out 50% of rat foetuses examined 100% of rabbit.
Necropsy.
Utero absorption sites counted need specimens that have not been pregnant before.
Even drugs that cannot cross placenta effect.
Safety Pharmacology
In vivo.
CNS.
Pulmonary.
Cardiovascular.
Safety Pharmacology - CNS
Mice or rats.
Behaviour and neurological effects. Motor activity. Body temp.
Safety Pharmacology - Respiratory
Rats or dogs.
Respiratory rate.
Tidal volume.
O2 saturation.
Safety Pharmacology - Cardiovascular
Dpgs
-BP/heart rate
-ECG
-hERG assay
-Repolarization
