Effect of temperature on the volume and compressibilities of some amphiphilic penicillins in aqueous solution

Abstract

Apparent molal volumes and adiabatic compressibilities of aqueous solutions of the amphiphilic anionic penicillins sodium cloxacillin and sodium dicloxacillin have been determined from density and ultrasound velocity measurements in the temperature range 288.15-313.15 K. Critical concentrations for aggregation of these drugs were obtained from both techniques. Positive deviation from the Debye-Hu ¨ckel limiting law of the apparent molal volume of both drugs at temperatures higher than 298.15 K provides evidence of pre-association at concentrations below the critical concentration. Apparent molal adiabatic compressibilities of the aggregates formed by the drugs, calculated by combining the ultrasound velocity and density data, were typical of those for a stacked aggregate.

Influence of SDS and two anionic hydrotropes on the micellized state of the triblock copolymer E71G7E71

“…This results from the less hydrophobic character of the cloxacillin molecule compared to the SDS one, which favors its presence free in solution (cloxacillin and dicloxacillin have cmcs of ca. ∼0.10 and 0.03 M in water, respectively [39]) and also due to its more voluminous head group, which is bulkier and would make difficult the accommodation of the hydrotropes molecules in the copolymer micelle and avoid the water-shielding effect of polyoxyethylene chains located in the copolymer corona micelle [34,46]. In the case of dicloxacillin, a slight and continuous decrease in r app,h is noted in the same concentration region (c < 0.01 M; see Fig.…”

A comparative study of the thermodynamic properties at the air–water interface and in the bulk of structurally related phenothiazine drugs aqueous solutions

“…Thus, the behaviour exhibited by these two drugs in the present work may therefore be of importance from a pharmacological point of view and would require further investigation. Positive values of B m have been also determined for the phenothiazine drugs chlorpromazine, promethazine and also promazine at T = 293.15 K [41], the antidepressants imipramine, clomipramine and nortriptyline hydrochlorides [12,41,57], the penicillins cloxacillin and dicloxacillin [58], classical surfactants [59], fluorosurfactants [52], and bile salts [60]. The existence of preaggregates below the critical concentration has been demonstrated for different amphiphilic tricyclic drugs by using microcalorimetry [23,61], osmotic [12], and frontal derivative chromatography [54] techniques.…”

"Synthesis and Charge Transfer Complex Studies of Carbazole Substituted Pyridopyrimidine With Some ?-Acceptors "

“…In pharmacokinetics, investigation of the physicochemical properties and mechanism of action of drug compounds in solution are very important. Spectroscopic and thermodynamic investigations lead to a measure of the strength of binding of the drug compounds to other substances present in living systems 11 . Electron Donor-Acceptor (EDA) complexes are an important phenomenon in biochemical and bioelectrochemical energy transfer processes 12 .…”