A Study of Aqueous Film Coating on Microcrystalline Hydroxy Apatite Complex Tablets

Water soluble polymers such as Hydroxy Propyl Methyl Cellulose (HPMC), Poly Vinyl Pyrrolidone (PVP), Carboxy Methyl Cellulose Sodium (CMC Na), and Methyl Cellulose as well as in combination of varying proportions are used in this study for the protective coating of Microcrystalline Hydroxy Apatite Complex (MCHC). The objective of this study was to investigate the effect of aqueous film coating on MCHC tablets evaluated by comparison with plain MCHC tablets and non-aqueous coated tablets. The parameters evaluated were the film smoothness, shininess, coating uniformity, percentage weight increase, hardness, disintegration time, dissolution study, moisture adsorption, stability and toxicity. An aqueous film coating solution in different combinations was applied on the tablets using a laboratory coating pan at 60C, in the atmospheric pressure. By using the same method non aqueous film coating solution was applied on the MCHC tablets and the tablet bed temperature maintained at 40C. The study has shown that HPMC and PVP combination in the proportion of 5% and 1% as coating material gave promising results in the evaluation of tablets. INTRODUCTION: Drug particles or tablets, which are sensitive to moisture degradation, may be protected against moisture uptake through film coating. The aqueous based system as coating material for solid dosage form has been gaining popularity owing to the fact, the organic based system presently followed are costly and also considered hazardous to health, safety and environment. The film coat must as a matter of necessity to dissolve or rupture after ingestion of the tablet in order not to impair disintegration and dissolution of the tablets. Consequently only water soluble or water swellable polymers are suitable candidates for such coating solutions. The important objective of this study is coating of dosage form is a necessary aspect in the manufacture of drug products to increase the elegance and to impart protection to the drug. This work introduces a new step in the coating process. Microcrystalline Hydroxy Apatite Complex (MCHC), a drug of natural origin was chosen as the experimental drug, which itself has a protein matrix, which promotes bone metabolism. The MCHC supplies the body both the inorganic and organic components of bone tissue in their natural proportions . The inorganic fraction consists of calcium, phosphorus, fluorine and trace elements . The organic matrix ossein consists mainly of collagen, amino acids and proteoglycon . In the present study, the emphasis was laid on the suitability of the different combinations of aqueous based polymers as coating material for MCHC tablets and they were evaluated and compared with non aqueous coated tablets for various parameters. Correspondence to Author: