Abstract

APPLICATION OF PHYTO PIGMENTS IN NOVEL ANALYTICAL METHOD DEVELOPMENT FOR SOME AMIDE GROUP CONTAINING DRUGS

Sushama Garud, Sachin Pishawikar*, Suresh Killedar and Sameer Nadaf

Abstract

Introduction: The polyphenolic structural features present in synthetic dyes like methyl orange, bromocresol green, thymol blue plays a role in their use as acid base indicators as well as colour complex forming agents in development of spectrophotometric methods. Nature is full of natural colour pigments. Phytochemical investigation of extract of Delonix regia flowers shows presence of anthocyanins which have similar polyphenolic nature. Hence as novelty, in present work a successful attempt has been done to develop simple and accurate spectrophotometric method for estimation of glipizide and repaglinide. Material and Methods: The estimation of glipizide and repaglinide is done on the basis of formation of colour complex between amide group and polyphenolic structural feature present in extracted pigment of Delonix regia flowers. Stock solution of 100μg/ml was prepared and serial dilutions were done to get concentration range of 4 to 20 μg/ml for glipizide and 5 to 40 μg/ml for repaglinide. Result: The absorbance of the coloured complex was at λmax of 610 nm for glipizide and at 605 nm for repaglinide against reagent blank. Validation of method was done as per ICH (Q2) guidelines. Beer’s law range was found to be 4 to 20 μg/ml for glipizide and 5 to 40 μg/ml for repaglinide with correlation coefficient 0.9994 and 0.9996 respectively. The LOD and LOQ was found to be 0.2681 and 0.7962 respectively. The existence of Keto-enol tautomerism shown by polyphenolic compounds and presence of loan pair of electron on nitrogen of amide group were found to contribute in formation of colour-complex between amide and the colour pigment which was confirmed by IR. Conclusion: It can be concluded that, use of natural colour pigments can be done in development of a simple, accurate, sensitive and reliable spectrophotometric and can be used in routine quantitative analysis of different API in bulk as well as pharmaceutical formulation.

Keywords: Glipizide; Repaglinide; spectrophotometry; Delonix regia; validation.