Abstract
The main objective of this work was to study the dissolution kinetics of poorly water-soluble drugs, indomethacin and ibuprofen, from formulated capsules or interactive mixtures containing fine lactose (FL), as ternary additive, and coarse lactose as carrier compared with selected commercially indomethacin capsules and to investigate the role of FL-drug size ratio on the dissolution.
It was found that the addition of FL in lactose-indomethacin capsules enhanced the dissolution of indomethacin while it has decreased the dissolution of ibuprofen from the lactose-ibuprofen mixtures. The particle size distributions for drugs and fine lactose used in this study suggested that the difference in dissolution behaviour for the two drugs could be due to the FL-drug ratio. Results obtained from the application of different dissolution kinetic equations showed that the first-order equation can best describe the kinetic of the dissolution for RothacinA (R), IndylonA (R), IndominA (R) and ternary-formulated capsules of indomethacin, while the dissolution from the binary-formulated indomethacin capsules showed that the dissolution cannot be described by zero-order or first-order equations. For ibuprofen mixtures, the results showed that the release followed the first-order kinetic for both systems, binary and ternary mixtures. Results obtained from Peppas equation showed that all indomethacin formulations used in this study released the drug by Fickian release with release exponent (n) < 0.45, while all ibuprofen formulations used in this study released the drug by non-Fickian (anomalous) release with release exponent (n) > 0.45 and > 0.89.
The FL-drug ratio could give an explanation to the enhanced dissolution of indomethacin and decreased dissolution of ibuprofen from interactive mixtures.