Modulation of Aggregation Behaviour of Amphiphlic Drug and Surfactant Mixture under the Influence of Neutral Polymer (original) (raw)
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Micellization of mixtures of amphiphilic drugs and cationic surfactants: A detailed study
Colloids and Surfaces B-biointerfaces
The micellization behaviors of two amphiphilic drugs ((amitriptyline hydrochloride (AMT) and imipramine hydrochloride (IMP)) in presence of cationic surfactants (conventional as well as gemini) have been investigated conductometrically at four mole fractions and four temperatures. The critical micelle concentration (cmc) values come out to be lower than cmcid values (cmcid is the cmc value at ideal mixing state) indicating attractive interactions between the two components in mixed micelles. Micellar mole fractions of surfactants (X1 and X1M), calculated by Rubingh and Motomura models, are always greater than X1id (micellar mole fraction at ideal mixing). The rigid structure of drugs decreases their contribution in mixed micelles as compared to that predicted by X1id values. 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 hydrophobic part of the drug at or above certain temperature which is different for the two drugs.► Micellization of amphiphilic drug–cationic surfactant systems have been analyzed. ► Rubingh and Motomura models show higher contribution of surfactants in mixed micelles. ► The negative β values suggest attractive interactions between the components. ► For drug/drug–surfactant systems, ΔHm° values change from negative to positive with temperature.
The Journal of Chemical Thermodynamics, 2014
Herein, we have accounted for the interaction between a non-steroidal anti-inflammatory drug ibuprofen (IBF) and non-ionic surfactant polyethoxyglycol t-octylphenyl ether (TX-100 (4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol) and TX-114 ((1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol)), in aqueous urea solutions using tensiometric and fluorimetric techniques at T = 298.15 K. Surface tension measurements were carried out to evaluate the critical micelle concentrations (cmc) of the drug and surfactant as well as their mixtures of varying compositions. An increase in the surface charge of the micelles was observed with the addition of urea followed by halt of micelles formation. Various physicochemical parameters, such as, cmc values of the mixture, micellar mass fraction (X Rub 1 ) of surfactants (TX-100/TX-114), interaction parameters (b) at the monolayer air-water interface and in bulk solutions, different thermodynamic parameters and activity coefficients (f m 1 ; f m 2 ) for the non-ionic surfactant and drug in the mixed micelles, were determined by using the approach of Clint, of Rubingh, and of Rosen. All results identified synergism and attractive interactions in the mixed systems of (drug-surfactant) mixtures and showed effective involvement of the non-ionic surfactant (TX-100/TX-114) component in the mixture. Micelle aggregation numbers (N agg ), evaluated by using steady-state fluorescence quenching studies, suggest that the contribution of non-ionic surfactant was always more than that of the drug. Micropolarity (I 1 /I 3 ), Stern-Volmer binding constants (K sv ) and the dielectric constant (D exp ) of mixed systems have also supported the synergistic behavior of the mixed amphiphilic systems.
Colloids and Surfaces B: Biointerfaces, 2014
In the present work, the micellization, adsorption and aggregation behavior of mixed drug-surfactant systems, in the absence and presence of electrolyte (100 mM NaCl) were investigated by surface tension and fluorescence measurements. The critical micelle concentrations (cmc) of the mixtures fall between the values of the individual components, which indicate nonideal behavior of mixing of the components. On the basis of regular solution theory (RST), the micellar mole fractions of surfactant (X 1 ) and interaction parameter in solution (ˇ) were evaluated, while their interfacial mole fractions (X 1 ) and interaction parameters at the interface (ˇ ) were calculated using Rosen's model. The results indicate that the surfactant's contribution is greater than that of the drug both at the interface and in micelles. The short and rigid hydrophobic structure of the drug resists its participation in micelle formation more than in the monolayer, leading to X 1 < X 1 . Values of the surface excess ( max ) and minimum area per head group (A min ) indicate attractive interactions. max increases and A min decreases as the surfactant mole fraction increases. The results have applicability in model drug delivery.
Journal of Molecular Liquids, 2014
Imipramine hydrochloride (IMP) is a drug which is amphiphilic. Its interaction with gemini surfactants 14-s-14 (s = 4, 5, 6) has been investigated at different temperatures employing conductimetric measurements. The experimentally determined critical micelle concentration (cmc) values come out to be lower than the ideal values (cmc idthe cmc value at ideal mixing state) suggesting attractive interactions between the mixture components. The micellar mole fraction of surfactant in the mixed systems (X 1
Journal of Molecular Liquids, 2014
The present work is aimed at studying the interactions of two cationic amphiphilic drugs, viz. imipramine hydrochloride (IMP) and promethazine hydrochloride (PMT), with several polymers (cationic, nonionic, and anionic) in aqueous solutions by using tensiometric and conductivity measurements. The onset of interaction, the socalled critical aggregation concentration (CAC), decreases on increasing the polymer concentrations whereas the critical micelle concentration (CMC) of the drugs rises. The strength of interaction was found to be dependent upon the nature of the polymers. The interaction between the anionic polymer NaCMC and drugs was maximum while it was minimum in case of drug-cationic polymer HECEQ system. The interfacial parameters like Gibbs surface excess (Γ max) and the minimum area occupied by the drug monomer (A min) have been estimated. The free energies of adsorption (ΔG ad 0), aggregation (ΔG a 0), micellization (ΔG m 0) and transfer (ΔG t 0) associated with the interactions between the drugs and polymers have also been evaluated.
Polymers, 2021
In this paper, the interaction of imipramine hydrochloride (IMP, antidepressant drug) and a non-ionic surfactant Triton X-100 (TX-100) mixture in five different ratios through the tensiometric method in different solvents (aqueous/0.050 mol·kg−1 aqueous NaCl/0.250 mol·kg−1 aqueous urea (U)) were examined thoroughly at a temperature of 298 K. UV–Visible studies in an aqueous system of IMP + TX-100 mixtures were also investigated and discussed in detail. The pure (IMP and TX-100) along with the mixtures’ critical micelle concentration (cmc) were assessed by a tensiometric technique. The obtained deviation of the mixtures’ cmc values from their ideal values revealed the nonideal behavior of IMP + TX-100 mixtures amongst IMP and TX-100. Compared to aqueous systems, in the presence of aqueous NaCl, several changes in micelles/mixed micelles occurred, and hence a synergism/attractive interaction amongst components was found increased while in the existence of U, the synergism/attractive i...
Study of Mixed Micelles and Interaction Parameters for Polymeric Nonionic and Normal Surfactants
Journal of Nanoscience and Nanotechnology, 2006
Surface tension (ST) measurements were carried out on various binary mixtures of the "normal" surfactants, such as nonionic surfactant, hexaethylene glycol mono-n-dodecyl ether(C 12 EO 6 , and cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and polymeric copolymer, Pluronic F127, F127(PPO)-g-PVP, and F127(PEO)-g-PVP. In all cases mixed micellar aggregates were formed and critical micellar concentrations of binary mixtures containing different mole fractions of the surfactants were measured using surface tension measurement. In the region where mixed micelles are formed, the interaction of two "normal" surfactants and three "polymeric" nonionic surfactants showed synergistic behavior and the results were analyzed using a interaction parameter, , which characterize the interaction in the mixed micelle and introduced by a regular solution theory. The regular solution theory can be applied to describe the interaction between TTAB and C 12 EO 6 , and graft polymeric surfactants systems. The results discussed in this paper showed regular solution theory has broader extent of application.
Journal of Surfactants and Detergents, 2017
The interactions of two gemini surfactants (16s-16, s = 5, 6) and their conventional counterpart cetyltrimethylammonium bromide (CTAB) with polyethylene glycols (PEG 3000 and PEG 35000) have been investigated using conductivity, steady state fluorescence, viscosity and TEM techniques. The results indicate that there is no interaction between the PEG 3000/CTAB complex at lower polymer concentrations. However, a very weak interaction is observed at higher concentrations (0.5 and 1.0 wt% PEG 3000), while PEG 3000 and PEG 35000 interact with the gemini surfactants. Both critical aggregation concentration (CAC) and critical micelle concentration (CMC) increases with polymer concentration but are independent of the polymer molecular weight. From steady state fluorescence it is found that the addition of PEG results in no drastic decrease in the aggregation number (N) for all surfactants. This suggests that the atmosphere surrounding the polyion-bound micelles, with respect to the influence on the forces acting at the micelle surface, is equivalent to the counterion/water atmosphere surrounding free micelles. The relative viscosity (g r) results show an enhancement in g r for all the surfactants. The increase in g r is quite significant with gemini surfactants. Polymer-surfactant interaction also depends on the polymer molecular weight. Also, the interaction seems to affect both inter polymer-polymer association as well as chain expansion. Additionally the surfactant induced changes in the polymer conformation depicted by TEM study at the micro structural level confirmed previously observed interactions determined by different analytical techniques.