Amphiphilic Drug Promethazine Hydrochloride Research Articles

Micellization behavior of the amphiphilic drug promethazine hydrochloride with 1-decyl-3-methylimidazolium chloride and its thermodynamic characteristics

The micellization behavior of promethazine hydrochloride (PMT) with 1-decyl-3-methylimidazolium hydrochloride, [C10mim] [Cl], at different temperatures was investigated by using electrical conductivity. The system thermodynamic properties were also studied by calculating various thermodynamic parameters (viz., the standard Gibbs energy change, ΔG°m, the standard enthalpy change, ΔH°m, the standard entropy change, ΔS°m), that favor the micellization in binary mixtures of PMT–[C10mim][Cl] compared with the pure counterparts, at two mole fractions of PMT. The synergistic interaction is examined using Regular Solution Theory for PMT–[C10mim] [Cl] binary mixtures, through the interaction parameter (β) and activity coefficient (f1 and f2) values. The synergism is also revealed in the deviations in the critical micelle concentration (cmc) from the ideal critical micelle concentration (cmc*) and micellar mole fraction (X1) from ideal micellar mole fraction (X1ideal) values. The value of excess free energy (ΔGex) for α1=0.6 at 308K favor the better condition for the formation of the most stable and compact mixed micelles.

Aggregation behaviour of amphiphilic drug and bile salt mixtures at different compositions and temperatures

The micellization and adsorption behaviour of the amphiphilic drug promethazine hydrochloride (PMT – a phenothiazine) and bile salts mixtures were analyzed at different compositions in pure and mixed states in aqueous solutions. By using regular solution theory (RST) and Rosen’s model different physicochemical properties such as critical micellar concentration (cmc), micellar composition, surface excess concentration (Γmax), minimum area per molecule (Amin), interaction parameters (βm,βσ), energetic parameters of micellization as well as other micellar and surface properties have been determined. The values of interaction parameters (β) and activity coefficients f1 and f2 (for both, in mixed monolayer as well as in mixed micelles) indicate the synergistic behaviour. The thermodynamic parameters propose release of water from the hydrophobic portion of the drug at higher temperatures.

Mixed micellization between amphiphilic drug promethazine hydrochloride and cationic surfactant (conventional as well as gemini)

The micellization behavior of an amphiphilic drug (promethazine hydrochloride (PMT)) in the presence of cationic surfactants (conventional as well as gemini) has been investigated conductometrically at different concentrations and temperatures. The micellar mole fractions of the surfactant (X1Rub, X1M, X1Rod, and X1id), calculated by different proposed models, show greater contribution of surfactant in mixed micelle and increases with the increase in concentration of the surfactant. Although α1 (mole fraction of surfactant) is higher for DTAB than that of 12-4-12, the contribution of 12-4-12 is almost equal to that of DTAB. The interaction parameter (β) is negative at all temperatures and at all compositions indicating attractive interactions. Activity coefficients (f1 and f2) are always less than unity suggesting nonideality in the systems. Thermodynamic parameters suggest dehydration of the hydrophobic part of the drug at or above a certain temperature.

Cloud point variation of amphiphilic drug promethazine hydrochloride with added surfactants

In this paper we report clouding phenomenon occurring in an amphiphilic phenothiazine drug promethazine hydrochloride (PMT) in presence of surfactants. Cationic and nonionic surfactants increase the CP of 75 mM PMT solutions (prepared in 10 mM sodium phosphate buffer). These surfactants form mixed micelles with PMT. Anionic surfactants also form mixed micelles with the drug but the CP behavior is different by showing a peaked behavior. At low concentrations, anionic surfactants hinder micelle formation by forming ion-pairs whereas the usual CP decreasing effect at higher concentrations is due to mixed micellization. The CP behavior of 75 mM PMT + 50 mM TBAB + surfactant systems is also explored which is found similar to PMT + surfactant systems with the difference only in magnitude of the clouding temperature.

Micellization Behavior of an Amphiphilic Drug Promethazine Hydrochloride-Surfactant System in an Aqueous Medium

The behavior of the mixed amphiphilic drug promethazine hydrochloride (PMT) and cationic as well as nonionic surfactants was studied by tensiometry. The cmc values of the PMT-surfactant systems decrease at a surfactant mole fraction of 0.1 and it then becomes constant. The critical micelle concentration (cmc) values are lower than the ideal cmc (cmc * ) values for PMT/TX-100, PMT/TX-114, PMT/Tween 20, and PMT/Tween 60 systems. For the PMT/Tween 40, PMT/Tween 80, PMT/CPC, and PMT/CPB systems the cmc values are close to the cmc * values. This indicates that PMT forms mixed micelles with these surfactants by attractive interactions. The surface excess (Γmax) decreases in the presence of surfactants. The rigid structure of the drug makes adsorption easier and the contribution of the surfactant at the interface decreases. The interaction parameters β m (for the mixed micelles) and β σ (for the mixed monolayer) are negative indicating attraction among the mixed components.

Mixed micelles of amphiphilic drug promethazine hydrochloride and surfactants (conventional and gemini) at 293.15 K to 308.15 K: Composition, interaction and stability of the aggregates

Micellization of an amphiphilic phenothiazine drug promethazine hydrochloride (PMT) in presence of conventional (CTAB and TTAB) as well as gemini (16- s-16 and 14- s-14, s = 4–6) cationic surfactants has been studied conductometrically at different temperatures. Critical micelle concentration values (cmc and cmc id) indicate mixed micelle formation among the two components. Micellar mole fractions of surfactants ( X 1, X 1 M and X 1 id ) show greater contribution of surfactants. Interaction parameter, β, suggests attractive interactions in the mixed systems. The thermodynamic parameters suggest dehydration of hydrophobic part of the drug at higher temperatures.

Cloud Point Phenomenon in Amphiphilic Drug Promethazine Hydrochloride+Electrolyte Systems

Herein we report clouding phenomenon occurring in amphiphilic drug promethazine hydrochloride (PMT) in the presence of electrolytes. The CP of 50 mM drug solution, prepared in 10 mM sodium phosphate buffer, was found to decrease with increasing pH due to deprotonation of drug molecules at high pH. Addition of inorganic salts (KF, KCl and KBr) to drug solutions at fixed pH (6.7) and drug concentration (50 mM) caused an increase in CP. The results have been discussed on the desorption/adsorption of counterions to the headgroups. Cations also increased the CP by affecting the water structure with their effectiveness being in the order: Li+<Na+<K+<NH4 +. In the presence of NaCl, increase in drug concentration increased the CP while increase in pH showed an opposite trend.