Influence of diluents and manufacturing method on the in vitro dissolution of carteolol hydrochloride matrix tablets

Abstract

The release behaviour of carteolol hydrochloride matrix tablets was investigated as a function of filler nature (Emcompress ®, mannitol, PEG 6000 and lactose), type of wetting liquid (Eudragit ® L 12.5% and isopropanol-acetone mixture 6:4) and mode of filler incorporation. The values of the technological parameters suggest that hardness was the most significantly affected by the three formulation factors considered. The strongest influence over the technological parameters was exerted by the mode of filler incorporation. The kinetic data conformed with the Higuchi square root equation, except for the lots containing mannitol and isopropanol-acetone mixture that conformed to a first-order plot. The lot containing Emcompress ® and isopropanol-acetone mixture displayed acceptable linearity with both plots. Therefore, a non-linear regression procedure and reduced time method were used to define with precision the kinetic model followed by this formulation. Release parameters such as the Higuchi rate constant, ts0 and dissolution efficiency were calculated. Lots containing mannitol presented more rapid release rates due to the high solubility of this filler. On the other hand, the use of PEG 6000 as diluent significantly decreased drug release. The influence of technological parameters on the release of these systems was also examined, an inverse relationship between hardness and dissolution efficiency being found.