The objective of the study is to evaluate the individual main effects and combined (or interaction) effects of HPβ cyclodextrin (HPβCD), surfactant (Poloxamer 407) and PVP K30 on the solubility and dissolution rate of pioglitazone in a series of 23 factorial experiments. The solubility of pioglitazone in eight selected fluids containing HPβCD, Poloxamer 407 and PVP K30 as per 23 factorial study was determined. HPβCD alone gave a marginal increase (2.54 fold) in the solubility of pioglitazone. Combination of HPβCD with Poloxamer 407 and PVP K30 resulted in a higher enhancement in the solubility of pioglitazone, 4.60 fold with HPβCD - Poloxamer 407 and 3.32 fold with HPβCD - PVP K30. Solid inclusion complexes of pioglitazone- HPβCD were prepared with and without Poloxamer 407 and PVP K30 by kneading method as per 23-factorial design and were evaluated. ANOVA indicated that the individual main effects of HPβCD, Poloxamer 407 and PVP K30 and their combined effects in enhancing the solubility and dissolution rate (K1) were highly significant (P < 0.01). Combination of HPβCD with Poloxamer 407 and PVP K30 also gave significantly higher dissolution rates (K1) when compared to HPβCD alone. Poloxamer 407 and PVP K30 alone also gave a higher enhancement in the solubility and dissolution rate of pioglitazone. Hence a combination of HPβCD with Poloxamer 407 and PVP K30 or Poloxamer 407 and PVP K30 alone is recommended to enhance the solubility and dissolution rate of pioglitazone, a BCS class II poorly soluble drug.
