Available online at www.scholarsresearchlibrary.com Scholars Research Library Der Pharmacia Lettre, 2010, 2(6): 68-75 (http://scholarsresearchlibrary.com/archive.html) ISSN 0975-5071 USA CODEN: DPLEB4 68 Scholar Research Library Formulation and evaluation of Diltiazem hydrochloride matrix tablets using natural polymer Ashish Kumar Gupta *1 , Satyawan Singh 1 , S. N.Pandeya 1 , Aparna Misra 1 , Abhishek Gupta 1 , Kiran Gupta 2 , M. Bajpai 3 1 Department of Pharmacy, Saroj Institute of Technology and Management, Lucknow,UP, INDIA 2 Chemistry Department, MNINT Allahabad, UP, INDIA 3 Department of Pharmacy, Raj Kumar Goel Institute of Technology, Ghaziabad, UP, INDIA ______________________________________________________________________________ ABSTRACT The objective of present study was to formulate and evaluate hydrophilic matrix tablets of Diltiazem hydrochloride achieve a controlled and sustained drug release manner with reduced frequency of drug administration, reduced side effects and improved patient compliance. Matrix tablets of Diltiazem hydrochloride were prepared using natural polymers like Xanthan Gum, Guar gu, Sodium alginate and carrageenan. All the batches were evaluated for thickness, weight variation, hardness, drug content uniformity and in-vitro drug release characteristics as per USP XXIV monograph. The release kinetics and mechanism of drug release by regression coefficient analysis and various exponential release model equations were also investigated. Tablets having xanthan gum gave more sustained release than other hydrophilic polymers studied. Amount of polymers and presence of different diluents significantly affected the drug release. It was observed that all the fabricated tablets delivered the drug following Higuchi diffusion mechanism. Keywords: Diltiazem hydrochloride; Xanthan Gum; Guar gum; Sodium Carboxymethyl Cellulose, Higuchi diffusion. ______________________________________________________________________________ INTRODUCTION Diltiazem hydrochloride (DTZ) is a calcium channel blocker acting block Ca +2 entry by preventing L-type calcium channels. It is widely prescribed for the treatment of hypertension and angina. Bioavailability of DTZ is 30% to 40% owing to first pass metabolism. It has an elimination half-life of 3.5 hours. Therefore DTZ requires multiple drug therapy in order to