www.derpharmachemica.com t Available online a Scholars Research Library Der Pharma Chemica, 2014, 6(2):20-23 (http://derpharmachemica.com/archive.html) ISSN 0975-413X CODEN (USA): PCHHAX 20 www.scholarsresearchlibrary.com Colorimetric estimation of few pharmaceutical agents miglitol, carvedilol and alverine citrate in pure and tablet dosage forms using MBTH R. Vijayalakshmi*, Poorna Chandrarao 1 ,Vsh. Naveena, Aishwarya Maithili, K. Rajasekhar and M. D. Dhanaraju * GIET School of Pharmacy, Chaitanya Knowledge city, Rajahmundry, India 1 Mahindra Satyam, Hyderabad, Andhra Pradesh, India _____________________________________________________________________________________________ ABSTRACT The objective of the present work is to develop simple, precise and accurate colorimetric methods for the estimation of miglitol (MIG), carvedilol (CRV) and alverine citrate (ALV) using MBTH reagent. The method was developed on Perkin Elmer LAMBDA 25 UV –VIS spectrophotometer with 1cm quartz cells. MBTH (3-methyl benzothiazolin-2- one-hydrazone), in the presence of acidified ferric chloride for MIG and CRV; cerric ammonium sulphate for ALV undergoes oxidative coupling and forms electrophilic intermediate; active coupling species. The drugs reacts with the active coupling species to give greenish blue coloured solution with maximum absorbance measured at 623 nm for MIG; 635 nm for ALV, blue coloured solution monitored at 561 nm for CRV. The order of addition followed is CRV followed by oxidizing agent and MBTH and MIG/ALV followed by MBTH and oxidizing agent. The linearity was assessed and found to be in 10-30 μg/mL for MIG, 20-100 μg/mL for CRV and 50-250 μg/mL for ALV, respectively. The colorimetric methods were extensively validated as per ICH guidelines and all the parameters were within the acceptance criteria with correlation of 0.999 and percentage RSD less than 2 for all the three methods. The methods were proved to be more accurate, simple, precise and rapid by statistical analysis. Key words: Miglitol (MIG), carvedilol (CRV), alverine citrate (ALV), MBTH (3-methyl benzothiazolin-2-one- hydrazone), ferric chloride and cerric ammonium sulphate (CAS). _____________________________________________________________________________________________ INTRODUCTION Miglitol, chemically is ((2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl) piperidine-3,4,5-triol, used in curing type II diabetes mellitus. Carvedilol is chemically known as (±)-[3-(9H-carbazol-4-yloxy)-2-hydroxypropyl][2-(2- methoxyphenoxy)ethyl]amine, a nonselective beta-adrenoreceptor blocking agent used in the treatment of hypertension Literature survey of these drugs revealed that there are methods for the determination of MIG [1-3] , CRV [4-14] and ALV [15-17] by LC and spectrophotometry. The purpose of this work is to develop a method in economic point of view and for regular analysis. Effort was put to develop a novel, simple, rapid, economic, precise, efficient colorimetric methods for quantitative analysis of miglitol, carvedilol and alverine citrate and to validate the methods according to ICH guidelines.