dissolution.

Quetiapine Fumarate is a antipsychotic agent indicated for treatment of Schizophrenia and Bipolar disorder. Quetiapine Fumarate is BCS Class II drug which is  poorly water soluble and may show dissolution limited absorption. Hence to improve dissolution rate and bioavailability, Solid dispersion of Quetiapine Fumarate by Solvent Evaporation method were prepared using 1:1, 1:2, 1:3, 1:4 and 1:5 ratios of Quetiapine Fumarate and Polyvinyl Pyrrolidone K30(PVP K30). The solid dispersion (SD) was characterized for physical appearance, solubility, FTIR, DSC, XRD studies and in vitro dissolution studies. FTIR study revealed that there was no drug-carrier chemical interaction in Solid dispersion. DSC studies revealed that, the peak observed for the melting of Quetiapine Fumarate is found to be absent in SD with PVP K30 carrier. XRD studies suggested that there has been a large change in the nature of Quetiapine Fumarate in the solid dispersion. Solubility of Quetiapine Fumarate from SD increased in distilled water. The drug content was found to be high and uniformly distributed in the formulation. The in vitro dissolution studies were carried using USP type II (paddle) type dissolution apparatus. The prepared Solid dispersion showed marked increase in the dissolution rate of Quetiapine Fumarate than that of pure drug. The Solid dispersion with PVP K30 (1:5) by Solvent evaporation method showed faster dissolution rate as compared to other Solid dispersions. It is concluded that dissolution of the Quetiapine Fumarate could be improved by the Solid dispersion.

The present study deals with the dissolution of an angiotensin II receptor antagonist drug, candesartan. Candesartan cilexetil is a poorly water-soluble prodrug. The in vitro dissolution testing of Candesartan cilexetil in water and buffer solutions is not possible. In the present study, an attempt was made to develop a dissolution medium for in vitro testing of the drug. A Kromacil C18, 5µm column having 150x4.6 mm internal diameter in isocratic mode with mobile phase containing mixture of buffer (pH 4.5) and acetonitrile in ratio of 45:55 was used. The flow rate was 1.5 mL/min and effluents were monitored by UV at 257 nm. The selection of the medium was made on the basis of solubility data of Candesartan cilexetil in different dissolution medium at 37 °C. Solubility data revealed that phosphate buffer (pH 6.5) consisting of 0.35% w/v tween 20 could be a suitable dissolution medium. Key words: Candesartan, solubility, buffer, dissolution.