Moisture sorption by tablet cores containing superdisintegrants during the aqueous film coating process
Abstract
A physical chemical analysis of the sorption of water molecules by tablets containing cross-linked sodium carboxymethylcellulose, sodium carboxymethystarch, and polyvinylpyrrolidone was carried out following aqueous film coating of formulated tablets. Characterization of the coated tablet properties (polymer film removed) was conducted using thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, mercury porosimetry and by measurement of water penetration rate, tablet tensile strength, and physical dimension. The depth of moisture penetration into the coated tablet core was determined by a moisture distribution study. Tablet residual moisture content, tensile strength, pore system characteristics, glass transition temperature of the amorphous polymer components, and physical dimensions were significantly affected after the coating operation. Significant difference was obtained between the level of moisture content in the various surface and core layers of the film coated tablet. This was attributed to the hydration and swelling of an individual disintegrant and microcrystalline cellulose particles or network structure as a result of the penetration of water from the aqueous film coating solution into the tablet matrix. An index of aqueous film coating efficiency in terms of its water removal capacity was determined at several levels of the operation parameters such as the inlet air temperature, coating solution spray rate, and the pan rotational speed. The measured properties of the coated tablets were selected as the dependent variables in this study. Regression techniques were used to arrive at 2nd order response functions, which mathematically describe the relation between the water removal efficiency of the coating process and the tablet response variables as a function of the above system parameters. The fitted quadratic regression models were utilized to generate graphical illustrations of the predicted response surfaces over the experimental range of the inlet air temperature and the spray rate. These were utilized to obtain optimal process conditions to control the amounts of moisture in the tablet bed. In addition, the functional linear relationships between the water removal efficiency of the coating process and the tablet response variables provided for the determination of a quantitative assessment of the effect of changes in processing conditions on the physico-chemical properties of the coated tablet dosage form.
Degree
Ph.D.
Advisors
Peck, Purdue University.
Subject Area
Pharmacology|Pharmaceuticals
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