A factorial study on the effects of HPβ cyclodextrin, PVP K30 and SLS on the solubility and dissolution rate of efavirenz.

ABSTRACT

The objective of the study is to evaluate the individual main effects and combined (or interaction) effects of Hydroxy propyl β cyclodextrin (HPβCD), poly vinyl pyrrolidone (PVP K30) and sodium lauryl sulphate (SLS) on the solubility and dissolution rate of efavirenz in a series of 23 factorial experiments. The solubility of efavirenz in eight selected fluids containing HPβCD, PVP K30 and SLS as per 23 factorial study was determined. The solubility of efavirenz was markedly enhanced by HPβCD (2.95 fold), PVP K30 (2.49 fold) and SLS (226.96 fold) individually. Combination of HPβCD with PVP K30 and SLS gave a markedly higher enhancement in the solubility of efavirenz than is possible with them individually. HPβCD in combination with PVP K30 and SLS gave respectively 4.05 and 387.63 fold increase in the solubility of efavirenz. Solid inclusion complexes of efavirenz - HPβCD were prepared with and without PVP K30 and SLS as per 23- factorial design by kneading method and were evaluated. ANOVA indicated that the individual main effects of HPβCD, PVP K30 and SLS and their combined effects in enhancing the solubility and dissolution rate (K1 )and dissolution efficiency (DE30 ) were highly significant (P < 0.01).HPβCD alone gave a 16.74 fold increase in the dissolution rate of efavirenz. HPβCD in combination with PVP K30 and SLS gave respectively 19.98 and 25.13 fold increase in the dissolution rate of efavirenz. HPβCD in combination with both PVP K30 and SLS gave highest enhancement (41.61 fold) in the dissolution rate of efavirenz. Combination of HPβCD with PVP K30 and SLS has markedly enhanced the solubility as well as dissolution rate of efavirenz than is possible with them individually. Hence a combination of HPβCD with PVP K30 and / or SLS is recommended to enhance the solubility and dissolution rate of efavirenz, a BCS class II drug.