The Effect of Water Soluble Polymers on Felodipine Aqueous Solubility and Complexing Abilities with Natural and Modified beta-Cyclodextrin

Purpose of this study was to investigate the effect of the presence of the watersoluble polymers viz hpmc, pvp and peg 6000 on aqueous solubility andcomplexation abilities of felodipine with or without presence of beta-cyclodextrin (betacd)and hp betacd by phase solubility studies . the data revealed the initial increase in drugsolubility followed by plateau in the presence of relatively low polymer concentrationi.e. 0.25-0.5 %w/v. phase solubility diagrams of felodipine in ternary systemshowed similar behaviour to binary system without betacd. addition of water solublepolymer to betacd solution improved betacd solubilizing efficiency due to increase inbetacd complexing power toward felodipine. in binary system solubility was found2.5 to about 10 time s higher than in water which was further improved in thepresence of 0.25% w/v water soluble polymer. ternary systems with betacd showedhighest increments in solubility towards felodipine, with 78.8 %, 81.8% and 74%improvement after the addition of 0.25% w/v hpmc, pvp and peg6000,respectively. our study confirmed that addition of small amounts of hydrophilicpolymer is useful strategy for improving the solublization and complexing abilit iesof cyclodextrins thus allowing less cyclodextrin to be needed to solubilize givenamount of drug . this offers economic advantage. all the polymers under studyshowed synergistic effect on felodipine cyclodextrin solublization by increasingcomplexation efficiency.the highest solubility improvement up to 81.8% wasobtained for betacd ternary system when 0.25% w/v of pvp was used.