Bioassay.pptx

Bioassay

1. NETES Institute of Pharmaceutical Sciences, Mirza Presented by- Jubair Sikdar Roll no-04 M. Pharm 2 nd semester Department of Pharmaceutical Chemistry BIOASSAY

2. CONTENTS Principle Types of bioassay Methods o f bioassay

3. Bioassay Definition: Bioassay is defined as the estimation of the potency of an active principle in a unit quantity of preparation or detection and measurement of the concentration of the substance in a preparation using biological methods . Principle: The basic principle of bioassay is to compare the test substance with the International Standard preparation of the same and to find out how much test substance is required to produce the same biological effect, as produced by the standard.

4. Types of Bioassay T here are two types of Bioassays. They are Qualitative Bioassay. Quantitative Bioassay . Qualitative bioassay: The objective is to determine what type of action a drug produces, by comparing its action with those of other substance of known activity. It can be used to detect small amounts of biologically active substance present at disease sites or released in pathology . Quantitative bioassay: The objective is determined as the amount if active constituent present in the drug preparation, for this purpose another preparation containing a known amount of active constituents is used as standard . Quantitative Bioassay is typically analyzed using the methods of biostatistics.

5. Methods of bioassays Direct methods : Matching method Bracket method (B) Indirect methods: Graphical or interpolation bioassay. 2 . Three point bioassay Four point bioassay ( A) Direct methods : Matching method : This test is performed by using frog's rectus abdominis muscle which placed in organ bath. Main aim of this method is to find out potency (or concentration) of the test sample by comparing the doses of standard acetylcholine and test acetylcholine.

6. In this method, Frog rectus abdominous muscle is placed in organ bath, with that DRC (Dose Response Curve) of drug (standard drug after that test drug) is carried out at various doses . 2. Bracket method : Bracketing Bioassay method is performed by selecting two standard doses, which will give a close bracket between lower dose and higher dose of standard when test dose is given . The method also carried out on frog rectus abdominous muscle. By taking of DRC of drug (for both standard and test) select two response of standard such that response to unknown dose is between these responses.

7. The potency of drug is calculated by using following equation. Potency of drug = mg/ml or µg/ml where S 1 = Standard dose of 1 S2 = Standard dose of 2 (B) Indirect methods : Graphical or Interpolation bioassay : This method is less time consuming and get reliable as compared to matching type of bioassay. Main advantage of this method is that the sensitivity of the tissue is determined by prior plotting of concentration response curve with known against as is the case with standard drug .  

8. Three point bioassay : This method is performed on isolated frog rectus abdominous muscle.• In this method two standard doses were selected which will give close bracket on either side of response produced by unknown. The response of 2 doses of standard ( S1, S2) the test is obtained by changing the order in successive cycle . The potency of the substance is determined by using the following formula . Potency of test solution= S ]log Where n1= Lower standard dose n2-Higher standard dose S1 and S 2 = Standard responses t = Test does (ml ) T1= Test response  

9. Four point bioassay : In four point bioassay comprises are based on analysis of dose response curve and the matching dose of standard and unknown are calculated by following formula . Potency ratio: Where, x1= Lower dose of standard drug x 2= Higher dose of standard drug y 1= Lower volume of test S1, S2, T1, T2= Mean responses of standard and test  

10. Reference 1. Srinivasa A. and Lakshmi N.: Pharmacological Screening Methods and Toxicology, First edition, 2022:101-115

11. OPEN TO DISCUSSION

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