The mixed micellization behavior of an amphiphilic antidepressant drug amitriptyline hydrochloride(AMT)in the presence of the conventional anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate(AOT)was studied at f...The mixed micellization behavior of an amphiphilic antidepressant drug amitriptyline hydrochloride(AMT)in the presence of the conventional anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate(AOT)was studied at five different temperatures and compositions by the conductometric technique.The critical micelle concentration(cmc)and critical micelle concentration at the ideal state(cmcid)values show mixed micelle formation between the components(i.e.,drug and AOT).The micellar mole fractions of the AOT(X1)values calculated using the Rubingh,Motomura,and Rodenas models show a higher contribution of AOT in the mixed micelles.The interaction parameter(β)is negative at all temperatures and the compositions show attractive interactions between the components.The activity coefficients(f1and f2)calculated using the different proposed models are always less than unity indicating non-ideality in the systems.TheΔGmΘ values were found to be negative for all the binary mixed systems.However,ΔHmΘ values for the pure drug as well as the drug-AOT mixed systems are negative at lower temperatures(293.15-303.15 K)and positive at higher temperatures(308.15 K and above).TheΔSmΘ values are positive at all temperatures but their magnitude was higher at T=308.15 K and above.The excess free energy of mixing(ΔGex)determined using the different proposed models also explains the stability of the mixed micelles compared to the pure drug(AMT)and surfactant micelles.展开更多
In the present study we report the micellization behavior of imipramine hydrochloride(IMP)in absence and presence of different concentrations of inorganic salts(LiCl,NaF,NaCl,NaBr,and KCl)and ureas(urea and thiourea)o...In the present study we report the micellization behavior of imipramine hydrochloride(IMP)in absence and presence of different concentrations of inorganic salts(LiCl,NaF,NaCl,NaBr,and KCl)and ureas(urea and thiourea)over the temperature range from 288.15 to 303.15 K.The critical micellization concentrations(cmc)of drug and drug+additive systems were determined by conductometric technique. With increasing temperature the cmc first increases then decreases.Maximum cmc values were obtained at 293.15 K with or without additives.In presence of inorganic salts the cmc value decreases which is explained on the basis of nature and ion size of the added ion.Urea and thiourea also decrease the cmc at low concentrations(0.2 mmo·lL -1 urea and 0.1 mmo·lL -1 thiourea),but,at higher concentrations,increase in cmc is observed.The related thermodynamic parameters are also evaluated and discussed.展开更多
基金supported by the Chemistry Department and Centre of Excellence for Advanced Materials Research,King Abdulaziz University,Jeddah,Saudi Arabia
文摘The mixed micellization behavior of an amphiphilic antidepressant drug amitriptyline hydrochloride(AMT)in the presence of the conventional anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate(AOT)was studied at five different temperatures and compositions by the conductometric technique.The critical micelle concentration(cmc)and critical micelle concentration at the ideal state(cmcid)values show mixed micelle formation between the components(i.e.,drug and AOT).The micellar mole fractions of the AOT(X1)values calculated using the Rubingh,Motomura,and Rodenas models show a higher contribution of AOT in the mixed micelles.The interaction parameter(β)is negative at all temperatures and the compositions show attractive interactions between the components.The activity coefficients(f1and f2)calculated using the different proposed models are always less than unity indicating non-ideality in the systems.TheΔGmΘ values were found to be negative for all the binary mixed systems.However,ΔHmΘ values for the pure drug as well as the drug-AOT mixed systems are negative at lower temperatures(293.15-303.15 K)and positive at higher temperatures(308.15 K and above).TheΔSmΘ values are positive at all temperatures but their magnitude was higher at T=308.15 K and above.The excess free energy of mixing(ΔGex)determined using the different proposed models also explains the stability of the mixed micelles compared to the pure drug(AMT)and surfactant micelles.
基金supported by the Council of Scientific and Industrial Research,New Delhi,India(01(2208)/08/EMR-II)
文摘In the present study we report the micellization behavior of imipramine hydrochloride(IMP)in absence and presence of different concentrations of inorganic salts(LiCl,NaF,NaCl,NaBr,and KCl)and ureas(urea and thiourea)over the temperature range from 288.15 to 303.15 K.The critical micellization concentrations(cmc)of drug and drug+additive systems were determined by conductometric technique. With increasing temperature the cmc first increases then decreases.Maximum cmc values were obtained at 293.15 K with or without additives.In presence of inorganic salts the cmc value decreases which is explained on the basis of nature and ion size of the added ion.Urea and thiourea also decrease the cmc at low concentrations(0.2 mmo·lL -1 urea and 0.1 mmo·lL -1 thiourea),but,at higher concentrations,increase in cmc is observed.The related thermodynamic parameters are also evaluated and discussed.
