The main aim of the study is to formulate sustained release matrix tablets of verapamil hydrochloride using hydrophobic carriers or meltable binders like stearic acid, carnauba wax and bees wax by melt granulation technique. The influence of a hydrophilic polymer like polyethylene glycol (PEG) was studied on the waxy matrices. Two grades of PEG (4000 and 6000) were used in the preparations. The granules were prepared and compressed into tablets and they are evaluated for their physicochemical properties and in vitro dissolution studies were done. The IR spectral analysis revealed that there are no interactions between drug and the polymers and are compatible with other. The release data were subjected to various release kinetic models and also compared with those of a commercial brand. The tablets prepared fulfilled all the official requirements according to the pharmacopeia. From the dissolution studies it was observed that carnauba wax acts a good retardant (more than 16 h). Among the two grades of PEG used 4000 and 6000, PEG 6000 increases the drug release to a greater extent than PEG 4000. It was concluded that hydrophobic carriers which act as very good retardants of the drug and also PEG can be used as a channeling agent in waxy matrices to regulate the release of the drug.
Key words: Bees wax, Carnauba wax, Melt granulation, PEG, Stearic acid, Sustained Release, Verapamil Hcl.
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