It is a hydrophobic drug which belongs to BCS class II and its half life is 5.1 h with 15–40% bioavailability.6 The aim of this study was to investigate the use of liquisolid technique in improving solubility and dissolution profile of candesartan cilexetil in the form of a liquisolid compact. New mathematical model is applied to calculate the required amounts of powder excipients (carrier and coating
materials) for the formulation of liquisolid systems.7 and 8 32 full factorial design is applied to study the effect of drug: excipient ratio (X1) and drug concentration in liquid medication (X2) on angle of repose, disintegration and dissolution of liquisolid compact of candesartan cilexetil. Candesartan cilexetil was kindly gifted by Indoco Remedies Ltd., Mumbai. Avicel PH 102, Aerosil 200, Tween find protocol 80, sodium starch glycolate, polyethylene glycol, Span 80, Tween 20, was purchased from Loba Chemie Ltd. Mumbai. Saturation solubility studies were carried out in
four different non-volatile solvents, i.e. polyethylene glycol 400, glycerin, selleck chemicals Tween 80 and Span 80. The desired quantity of the previously weighed solid candesartan cilexetil was dissolved in liquid vehicle (Tween 80). The solution was then sonicated for 15 min until a homogeneous drug solution was obtained. Next, the calculated weights (W) of the resulting liquid medications (equivalent to 8 mg drug) were incorporated into the calculated quantities of the carrier Avicel PH 102 and mixed thoroughly. The resulting wet mixture was then blended with the calculated amount of the coating material Aerosil 200 using a standard mixing process to form simple admixture. Two factors were varied, concentration of the drug in liquid vehicle (Tween 80) and carrier: coating ratios. Different liquid load factors (Lf) ranging from 0.2262 to 0.2703 were employed. Finally 5% w/w of sodium starch glycolate was mixed with the above mixture for 10 min. The final blend of liquisolid powder system was compressed crotamiton into tablets of desired weight of 8 mg strength
each by using 9 station tablet compression machine (Rimek Mini Press II-DL Karnavati), flat faced punch and die size of 12 mm were used. Directly compressed conventional tablets (CND) which is used for comparisons with liquisolid compacts is prepared by directly compressing powder mixture of candesartan cilexetil with Avicel PH 102, Aerosil 200,and sodium starch glycolate. Full factorial design was employed for the preparation of the liquisolid compacts. Two independent factors are studied, each at three levels, and experimental trials are performed on all 9 possible combinations. Excipients ratio (carrier: coating material, R) and percent drug concentration in liquid medication (cd %) were selected as independent variables. The angle of repose, disintegration time, percentage cumulative drug release at 30 min was selected as dependent variables.