Physicochemical Properties of Amphiphilic Drugs in Mixed Media

Abstract

The present work discusses the micellization and related parameters such as critical newlinemicelles concentration (CMC), degree of counterion dissociation (and#61537;), change in Gibbs newlineenergy of micellization (and#61508;Gm 0 ) and Gibbs energy of transfer (and#61508;Gtrans newline0 ) of two important newlineamphiphilic drugs (amitriptyline hydrochloride; AMT and promethazine newlinehydrochloride; PMT) and clouding behavior (CP) of the AMT drug with/without newlineadditives in various compositions of ethanol water (EtOH WR), ethylene glycol newlinewater (EG WR), and glyceroland#8722;water (GL WR) mixed media with a special focus on newlinetheir dependence with polarity changes. Organic solventand#8722;water mixed media find newlineapplications in industrial, chemical, and pharmaceutical areas. Ethanol (EtOH), newlineethylene glycol (EG) and glycerol (GL) are considered as good solvents in several newlineapplications such as coatings, detergents, cosmetics, pharmaceuticals, paint and ink newlineindustries. Decrease in conductivity of the drug solution and enhancement of CMC of newlineAMT and PMT were obtained with the rise in weight percentage (wt%) of the organic newlinesolvents in their mixed media at pH 6.7 and temperature 303.15 K. Among three newlinesolvents used as mixed media, the highly polar GL behaves as a better solvent and newlineoffers relatively low CMC values for the AMT and PMT drugs at various wt%, newlinewhereas CMC values were found to be higher in EtOHand#8722;WR mixed media and the trend newlinein CMC values for both the drugs in studied mixed media follow the order GL WR lt newlineEG WR lt EtOH WR. Such behavior is due to reduction in the polarity with the rise newlinein wt% of the studied mixed media (as it enhances the repulsive interactions between newlinethe cationic micellar headgroups of the AMT and PMT drugs). Decline in absorbance newlinevalues of solubilized sudan dye III in drug micellar solution with the increase in wt% newlineof studied mixed media supports results obtained from the conductivity measurements. newlineIt is understood from the results that and#61537; values of AMT and PMT increase regularly newlinewith increase in wt% of EtOHand#8722;WR mixed media.