Conformational study of ketoprofen by combined DFT calculations and Raman spectroscopy

Abstract

A conformational study of ketoprofen was carried out by both density functional theory (DFT) calculations and Raman spectroscopy. Nine different geometries were found to correspond to energy minimum conformations but only one of them was experimentally detected in the condensed phase spectra. Those rotations which interconvert the five most stable conformers were studied and the intramolecular interactions governing the corresponding conformational preferences were assessed. A thorough vibrational analysis was performed, leading to the assignment of both the solid and liquid spectra. Evidence for formation of intermolecular hydrogen bonds between carboxylic groups of adjacent ketoprofen molecules, leading to dimeric entities, was obtained.

Does PLGA microparticle swelling control drug release? New insight based on single particle swelling studies

“…The latter is much more soluble in the lipophilic PLGA than in water: According to Fig. 3 about 25% of ketoprofen can be dissolved in the dry PLGA matrix, whereas the drug's solubility in water at 25°C is only about 0.13 mg/mL [23]. Since only dissolved drug is available for diffusion, this leads to slower drug release.…”

The Effect of Geometrical Isomerism of 3,5‐Dicaffeoylquinic Acid on Its Binding Affinity to HIV‐Integrase Enzyme: A Molecular Docking Study

“…The low energy of the mono- cis isomers can be attributed to the fact that they have more intramolecular hydrogen bonds (IHBs) that act to stabilise their conformations than the 3 trans ,5 trans -diCQA isomer. Additionally, these mono- cis isomers have minimal steric interactions as compared to the high energy 3 cis ,5 cis -diCQA isomer; steric interactions have been shown to decrease the stability of molecules [26]. Due to the small difference observed in the relative energies of the isomers, it can be expected that these isomers coexist in plant material, with the exception of the 3 cis ,5 cis -diCQA isomer (5.096 kcal·mol −1 ) which is likely to exist in a very minor concentration.…”

Formulation and characterization of norethisterone transdermal patch as an alternative route to oral administration

“…This strongly suggests that diffusion may be referred to drug release mechanism. The Fickian kinetic model indicates that a drug is released through diffusion mechanism, while the nonFickian kinetic model indicates that drug release occurs through a hybrid mechanism of diffusion / erosion [16,17].…”

“…Diffused amount of drug from patches was determined spectrophotometrically. Release profiles were assessed kinetically by Higuchi and Korsmeyer -Peppas models [15,17]. Permeation coefficient (P) of the membrane was evaluated as Eq 1.…”