The present study aimed to design and evaluate hydrophilic matrix tablets of diltiazem hydrochloride, to achieve a controlled and sustained drug release with reduced frequency of drug administration, reduced side effects and improved patient compliance. Matrix tablets of diltiazem hydrochloride were prepared by using natural polymer like Gum Olibanum, hydrophilic polymer like hydroxypropylmethylcellulose (HPMC K4M) and different binders like starch, gelatin and polyethylene glycol (PEG-6000). All the batches were evaluated for weight uniformity, hardness, friability, drug content uniformity and in vitro drug release characteristics as per USP XXIV monograph. The drug release rates from matrix tablets were compared with marketed SR [ Dilzem SR (Torrent Pharma Ltd, India) ] formulations. The release kinetics and mechanism of drug release by regression coefficient analysis and higuchi constant and Peppas exponential release model equation were also investigated. It was observed that all the fabricated tablets delivered the drug following higuchi diffusion mechanism and the release mechanism of diltiazem hydrochloride from matrix tablets indicated Fickian transport mechanism. The binder’s effect on drug release from the dosage form was investigated. The insitu interations between the drug, polymers and excipients during wet granulation process are also investigated by DSC examination.
