Expt 2 interpolation bioassay
- 1. EXPERIMENT NO: 02 AIM : To estimate unknown concentration of acetylcholine solution by interpolation bioassay using hen’s ileum. Presented by: Prof. Mirza Anwar Baig Dept of Pharmcaology AIKTC, School of Pharmacy, New Panvel
- 2. REQUIREMENTS: 1. Basal tension – 0.5 gm 2. Extra load- 1 gm 3. Animal – Hen’s ileum tissue 4. Drug – Acetylcholine stock solution (10 μg/ml) & test solution. 5. Physiological solution – Tyrode solution 6. Contact time – 90sec 7. Magnification – 5-7 times.
- 3. PRINCIPLE:- o Interpolation method of bioassay is less time consuming and yet reliable as compared to matching type of bioassay. o Advantages: sensitivity of the tissue is first determined by prior plotting a concentration response curve with a known sample of acetylcholine. o If the linearity of the curve is good then one can do very accurate estimation of test substance as explained in the procedure.
- 4. PROCEDURE: Procedure for tissue mounting: 1. The fresh entire gastro-intestinal tract of healthy hen was obtained and kept in 200 ml Tyrode solution. 2. Aeration was provided immediately to the tissue. 3. Ileum was cut at the identified point & was transferred to a dish containing tyrode solution. 4. The 2cm long portion was cut & intestinal content was removed & freed from other tissues. 5. A thread was tied at each end taking care that the lumen was left open & thread does not cross it.
- 5. 6. The tissue was maintained for stabilization for 30 min with washing for every 10 min. 7. Basal tension was adjusted to 0.5 gm, magnification was kept 5-7 folds & bath volume to about 15 ml. 8. With the proper care the tissue was mounted in an oxygen delivered organ bath containing tyrode solution & temperature was maintained at 37 + 2 0 C. https://www.youtube.com/watch?v=4jUw6mkYoTU
- 6. Procedure for Interpolation Bioassay:- 1. Dose response of AcetylCholine was taken with the contact time of 90sec. 2. Repeat the first response till the height of the response obtained on the graph is same to ensure the stability of tissue preparation 3. Take at least 4 responses with increasing dose of acetylcholine or till you get the maximum response with higher concentration. 4. Take two responses for sub maximum dose and then select unknown dose of drug which fall in linear portion of concentration response curve 5. Properly labeled the graph. 6. Measure the height of response in mm and plot the log dose vs % response curve.
- 10. References: 1. Kulkarni S. K. Handbook of Experimental Pharmacology, Vallabh Prakashan, New Delhi. 2. Ghosh M.N. Fundamentals of Experimental Pharmacology Hilton & Company, Kolkata
- 11. Thank You