Characterization of Solid Binary Systems of Efavirenz and Hydroxypropyl-β-Cyclodextrin

ABSTRACT

Efavirenz is a widely prescribed anti-retroviral drug that belongs to BCS class II and exhibit low and variable oral bioavailability due to its poor aqueous solubility and it requires enhancement in solubility and dissolution rate for increasing its oral bioavailability. The aim of this study was to increase the solubility of Efavirenz (EFA) by complexing it with Hydroxypropyl-β-cyclodextrin (HPβCD). Solid binary systems were prepared by co-grinding and microwave irradiation methods. The interaction of EFA with HPβCD was evaluated by Phase solubility studies, in vitro dissolution studies and different analytical techniques including Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The apparent stability constant revealed EFA with HPβCD produces 11 M stoichiometric complex. The host guest interactions studied by FTIR and DSC confirmed true inclusion of EFA with HPβCD at 12 M. The Dissolution rates of EFA- HPβCD binary systems were faster when compared to physical mixture and pure drug. Overall the rank order of improvement in dissolution properties of Efavirenz with ratios is 12M > 11M and methods MW > CG > PM > Pure drug. One-way ANOVA suggest the DP60 and DE60 values were significantly higher (P<0.05) in solid binary systems prepared by microwave irradiation method when compared to co-grinding and its corresponding physical mixtures and pure drug.