ABSTRACT:
The research work was undertaken to improve dissolution rate of efavirenz (EFA). It has low aqueous solubility and low intrinsic dissolution rate. The solid dispersions were prepared by fusion method using 1:4(70%),1:4(80%), 1:8(70%) and 1:8(80%)ratio of EFA to the mixture of polyethylene glycol 400 (PEG)and polysorbate 80 (PS).The solid dispersions were characterized by differential scanning calorimetry (DSC),Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Dispersions were evaluated to determine drug content, practical yield and invitro drug release. The DSC thermogram of solid dispersion showed complete amorphization of drug. FTIR study revealed absence of any chemical interaction between EFA and excipients solid dispersion. Solubility of EFA in solid dispersion was increased in distilled water. The drug content was found to be high. The invitro dissolution studies showed marked increase in the dissolution rate than pure drug. The dispersion with 1:8, 80% of EFA and PEG showed faster dissolution rate. The feasibility of packing solid dispersion into capsule was also investigated. Capsule employing pure EFA and EFA solid dispersion were evaluated. Capsules with solid dispersions showed rapid and higher dissolution rate. The study revealed enhancement of dissolution of the EFA by PEG when formulated as solid dispersion.