The objective of the present study was to develop and characterize extended release tablets of Pramipexole dihydrochloride monohydrate to be taken once daily. The combination of different polymers like hydroxypropyl methyl cellulose (HPMC K 100M) and Eudragit L 100 in varying concentrations were studied to get the desired extended release profile over a period of 24 h. The granules were evaluated for angle of repose, bulk density, compressibility index, and drug content and found to be satisfactory. Hydroxypropylmethylcellulose (HPMC K100M) at 40% level in combination with methacrylic acid copolymer (Eudragit L100) at 3.3% level produced extended release Pramipexole dihydrochloride monohydrate matrix tablets. The drug release of optimized formulation (F4) was 100% which extended up to 24 h in vitro study. The drug release pattern from the optimized matrix formulation (F4) was diffusion controlled, obeying Higuchi equation. The innovator product Mirapex (0.375 mg) drug release profiles are shown to be followed first order release kinetics. In vivo bioavailability studies were conducted in rabbits and the pharmacokinetic parameters of the best formulation (F4) clearly indicated that the drug release was controlled and maintained constant plasma concentration upto 24 hours. The results suggested that combination of hydrophilic and hydrophobic polymers used in the preparation of extended release Pramipexole dihydrochloride monohydrate tablets, is a suitable method and it can perform therapeutically better.
