PRECLINICAL – ANIMAL STUDY

Enny Rohmawaty

Department Pharmacology and Therapy

Faculty of Medicine-UNPAD

Preclinical study/preclinical trial Preclinical trial - a laboratory test of a

new drug or a new medical device, usually done on animal subjects, to see if the hoped-for treatment really works and if it is safe to test on humans.

• Pre-Clinical Trials and Clinical Trials are the processes by which scientists test drugs and devices to see if they are SAFE and EFFECTIVE.

Experimental study In vitro and in vivo Animal models

Pharmacodynamic study

Toxicological study

• PHARMACODYNAMIC STUDIES

Effects / Efficacy Mechanism of action • TOXICOLOGICAL STUDIES Safety Spectrum

Pharmacodynamic study

In vitro: tissue, cell culture, blood component, etc

In vivo : whole animal Disease model : inflammatory,

dislipidemi, sepsis, Ca/ malignancy, etc Source of methode (literature) :

Guidelines, journal

Methodology of pharmacodynamic study

ANIMALS : Rodent or non-rodent (may depend on

desired effect) Healthy or diseased-animal model Sex : male and/or female Number : adequate for statistical analysis

Sample size determination:

Studies Comparing Two Group MeansTo compute sample size for continuous variables, it is necessary to obtain an estimate of the population standard deviation of the variable (s) and the magnitude of the difference (d) the investigator wishes to detect, often called the effect.Sample size is given by

where s is the standard deviation, d is the difference to be detected, and C is a constant dependent on the value of and selected. C can be determined from the table above, which gives values for C for two levels of and . Note that for 0.05 and 1- 0.9, C is 10.51 and 2C would be 21

Ralph B. Dell, Steve Holleran, R Ramakhakrishnan, Sample sice determination, 2002

Paired StudiesPaired studies compare values before and after an intervention in the same animal. In this case, data are analyzed by a paired t test, and the sample size is computed by

Ralph B. Dell, Steve Holleran, R Ramakhakrishnan, Sample sice determination, 2002

If the s, d and C cannot be determined Federer’s Formula

(t-1) (n-1) ≥ 15 t = number of treatmentn = number of sample

Federer WT. Experimental design, theory and application, 1967.

Data analysis

Program : SPSS Normality and homogeneity test Quantitative and Qualitative test Post hoc analysis

Route of administration : Per Oral- similar to human use

Dose : Based on Dose-Response Relationship One or more doses that provide a desired effect Dose conversion from human to animal may be used Calculation of ED50

Control group : Negative control

Solvent / vehicle group Positive control

Standard drug group To validate that a method works To obtain Relative Potency of drug candidate or herbal

medicines

Toxicological studies

IN VIVO TOXICOLOGICAL STUDIES A. GENERAL TESTS

SHORT TERM Acute Toxicity Test (LD50)

LONG TERM: Sub Acute Test Sub Chronic Test Chronic Test

B. LOCAL TOXICITY TEST Dermatological Preparation

C. SPECIAL TOXICITY TESTS Mutagenicity Test Carcinogenicity Test Reproductive and Development Toxicity Test

Animal models

Animal models are, at the best, analogous to human condition but no theory can be provided or refused by analogy. The truth is the evidence in animals can be a powerful device in support of virtually theory.

l Why are animals necessary in research?1. Diseases process in human and animals have similarities

2. Cell systems contain or manipulate only a part of the organ system.

3. Computer models lack the complexities of living entity .

Basic Reason Using Animals For Research

WMA DECLARATION OF HELSINKI (Tokyo 2004)

BASIC PRINCIPLES FOR ALL MEDICAL

RESEARCH

- Medical research involving human subjects

must conform to generally accepted scientific

principles, be based on a thorough knowledge

of the scientific literature, other relevant

sources of information, and on adequate

laboratory and, where appropriate, animal

experimentation.

- Appropriate caution must be exercised in the

conduct of research which may effect the

environment, and the welfare of animals used

for research must be respected

3R principles (Russell dan Burch, 1959)

Replacement

Reduction

Refinement

• correct model• genetic homogenity• use healthy animal

• Alternatifve methode• lower class of animal model

• caring• treatment• non-invasive methode• pain, stress, distress minimization

Five Freedoms = Animal welfare

“The council believes that the welfare of an animal ...

should be considered with reference to ‘Five

Freedoms’.

Freedom from hunger and thirst

Freedom from discomfort

Freedom from pain, injury and disease

Freedom to express normal behaviour

Freedom from fear and distress

(Farm Animal Welfare Council UK, 1993)

Group housing when ever possible

Human interactions

Nesting materials

Enrichment Devices for NHP

Enrichment devices for rodents: Igloo, nest etc.

Natural Behavior of burrowing & hiding