Drug release kinetics from matrix dosage form is governed by polymer swelling and erosion, drug dissolution/diffusion and polymeric combination. For the preparation of controlled release dosage form, hydrophilic, swellable polymers in optimum combination are essential. The major objective of the current study is to prepare Amoxicillin trihydrate-loaded bucco-matrix tablets by direct compression technique and to study the effect of ratio of HPMCK100M and HPMCK15M used in the formulation on the basic properties and on drug-release and permeation kinetics. The tablets offered satisfactory physicochemical results. The buccal strength, detachment force and bond strength of the tablets were good enough to hold the tablets in the buccal region. The drug release data generated during in vitro drug release study of bucco-matrix tablets in phosphate buffer pH 6.8 were evaluated by zero-order, first-order, Higuchi, Korsmeyer Peppas, and Kopcha models. Release exponent (n) of Korsmeyer- Peppas equation of the formulations exhibited diffusion as the principal mechanism of drug release. It was further confirmed by Kopcha model. Evaluation of diffusion and erosion terms in the Kopcha model showed that diffusion dominated swelling or erosion process through out the study. The permeation kinetics of the drug showed linearity when studied across goat buccal mucosa. Permeation coefficient of drug decreased with increase in % swelling index of the formulations.
From the results obtained, it can be concluded that a significant variation is observed in the In vitro release pattern of Amoxicillin trihydrate from the bucco-matrix tablet in relation to change the ratio of two grades of HPMC. There was variation in transport mechanism from quasi diffusion to anomalous by changing the ratio of HPMCK100M and HPMCK15M. Drug permeation through the membrane clearly indicates a skin-dependent permeation and is strongly controlled by the stratum corneum diffusion process. After getting successful results in in-vitro drug release as well as permeation study, ex-vivo drug release studies has to be done. In vivo studies are another future prospect to get a clear picture of IVIVC.
Key words: Bucco-matrix tablets, buccoadhesion, swelling index, release Kinetics, permeation kinetics
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