Structures and Hydrogen Bonding Recognition of Mefenamic Acid Form I Crystals in Mefenamic Acid/ Ethanol Solution

Abstract

Abstract-Mefenamic acid is one of the active pharmaceutical ingredientsthat exhibit polymorphism. An experimental study has found that Form I of mefenamic acid is produced fromcooling crystallization with ethanol as a solvent. Hydrogen bonding is considered as the fundamental factor that controls the polymorphism of mefenamic acid in ethanol. This work, in essence, was performed to verify this using molecular dynamics simulation.The simulation was performed using COMPASS force field available in Material Studio package.The resultof the simulation showed strong hydrogen bonding between oxygen and hydrogen in the carboxylic group.The results of the Fourier transform infrared spectroscopy analysis confirmed the existence of O-H, C-O and C=O bonds. These findings proved the presence of hydrogen bondsthat leads to the formation of hydrogen motif in Form I of mefenamic acid during crystallization process using ethanol as a solvent.

Effect of Impregnation of Biodegradable Polyesters with Polyphenols from Cistus linnaeus and Juglans regia Linnaeus Walnut Green Husk

“…Other characteristic bands that come from the phenol group vibrations are C–OH deformation vibrations (1370–1308 cm −1 ) and C–OH stretching vibrations (1172–1112 cm −1 ) [51]. Functional groups correlating with ethanol, which is the basis of a solution for polymer impregnation, have also been found on FTIR spectra of plant extract (3390 cm −1 and 3360 cm −1 —OH groups, 2980 cm −1 —CH groups, 1090 cm −1 and 1050 cm −1 —C–O groups) [52,53].…”

New Approach to Simultaneous In Situ Measurements of the Air/Liquid/Solid Interface Using PM-IRRAS

“…There is a clear presence of the adsorbed octadecanethiol SAM on the gold substrate (Figure ) in comparison to the ethanol liquid layer (Figure ). The characteristic peaks for identifying the adsorbed 1-octadecanethiol are the C–H stretching ν asym CH 3 at 2965 cm –1 , ν asym CH 2 at 2920 cm –1 , and ν sym CH 2 at 2852 cm –1 forming the SAM on gold. ,, The characteristic peaks for ethanol in our PM-IRRAS spectra are the ν asym CH 3 at 2972 cm –1 , ν sym CH 3 at 2880 cm –1 , and ν asym C–O at 1087 and 1045 cm –1 . , A new vibrational mode at 1660 cm –1 can be assigned to a CO stretch mode, probably from the partial oxidation of the ODT from air exposure. The broad OH stretching was not observed in the PM-IRRAS spectra, due to the decrease in signal from the half-wave position at 2100 cm –1 .…”

“…This suggests that the strong liquid-phase signals are detected from the ethanol layer at the air/liquid interface, as adsorption of ethanol to the surface of the gold substrate is not expected. Negative differential reflectance peaks located near 2981 and 1105 cm –1 could be attributed to the optical (real and imaginary) refractive index of ethanol or the alignment of each dipole moment of the C–H stretch and C–O stretch modes of ethanol , at the surface with respect to the plane of incidence. Another possibility is that these negative reflectance peaks are Berreman peaks that originate from p-polarized light interacting with the ethanol layer, which could act as a dielectric film. − When p-polarized infrared light, incident at a grazing angle, reflects off an ultrathin (ethanol) film on the gold surface, it is possible that a Berreman peak can arise.…”

“…31,32,43 The characteristic peaks for ethanol in our PM-IRRAS spectra are the ν asym CH 3 at 2972 cm −1 , ν sym CH 3 at 2880 cm −1 , and ν asym C−O at 1087 and 1045 cm −1 . 37,38 A new vibrational mode at 1660 cm −1 can be assigned to a CO stretch mode, probably from the partial oxidation of the ODT from air exposure. The broad OH stretching was not observed in the PM-IRRAS spectra, due to the decrease in signal from the halfwave position at 2100 cm −1 .…”

Superporous acrylic acid and HPMC hydrogels of mefenamic acid: Formulation, characterization and optimization by central composite design

“…Other peaks found at 2,929 cm −1 and at 1,055 cm −1 indicated the presence of C-H and O-C bonds respectively ( Iqbal et al, 2017 ; Iffat et al, 2020 ). The FTIR spectrum of MF presented characteristics peaks at 3,240 cm −1 , 1,120/1,188 cm −1 , 1,678 cm −1 relating to the presence of NH-H, C-N bond, and the COOH group respectively ( Mudalip et al, 2013 ). The IR spectrum of combined from of MF and HPMC exhibited no new peak confirming their presence without any chemical interaction.…”