The purpose of this study was to develop Freeze-dried Tablets (FDTs) for rapid absorption of carvedilol, an antihypertensive drug with poor solubility and poor bioavailability. Binary and ternary systems were first made of drug and different ratios of HPMC and Inutec and then were formulated into FDTs. Formulation of FDTs was based on 23 factorial design to study the influence of formulation variables namely, concentration of polymer matrix-former, concentration of collapse protectant and type of polymer used in formation of drug binary and ternary systems on tablet characteristics such as friability, in vitro disintegration time, in vivo disintegration time and initial dissolution. An optimized FDT formulation (RO) containing 2% gelatin, 1% glycine and binary system made of Drug: Inutec in the ratio 1:0.5 showed excellent mechanical strength, in vitro and in vivo disintegration times of less than 10 sec and more than 30% drug dissolved during the first 3 min compared to only 11% for the drug powder and 8% drug from an immediate release commercially available tablet (Carvepress). When the optimized FDT (RO) was administered to hypertensive rats it resulted in a significant decrease (p = 0.0015) in systolic blood pressure within the first 15 min compared to the immediate release conventional tablet as a reference which indicate the rapid dissolutionand absorption of carvedilol from the FDT.
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