Authors:Nouruddin Ali, Maha Hegazy, Mohammed Abdelkawy, and Eglal Abdelaleem
Accurate, sensitive, and precise high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the determination of Methocarbamol (ME) and its related substance (guaifenesin (GU)) in two ternary mixtures with ibuprofen (IB) and diclofenac potassium. The method depends on separation and quantification of the studied drugs on TLC silica gel 60 F254 plates using ethyl acetate-acetone-triethylamine-formic acid (62:35:6:0.3, by volume) as the developing system followed by densitometric measurement of the bands at 222 nm for the first mixture containing methocarbmol, IB, and GU and at 278 nm for the second mixture containing methocarbmol, diclofenac potassium, and GU. The proposed methods were successfully applied for the determination of ME, IB, and diclofenac potassium in the presence of ME-related substance (GU) either in bulk powder or in their pharmaceutical formulations.
Authors:Azza A. Moustafa, Maha A. Hegazy, Dalia Mohamed, and Omnia Ali
Simple, accurate, precise, sensitive, and validated high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC)‒densitometric methods were developed for the simultaneous determination of chlorpheniramine maleate (CPM), pseudoephedrine HCl (PSE), and ibuprofen (IBF) in tablet dosage form. In method A, reversed-phase (RP)-HPLC analysis was performed on Zorbax C8 column (150 mm × 4.6 mm, 5 μm particle size i.d.), using a mobile phase consisting of methanol–acetonitrile–distilled water (pH 4) using orthophosphoric acid in the ratio (80:10:10, v/v) and flow rate of 0.7 mL min−1. Quantification was achieved with ultraviolet (UV) detection at 220 nm. In method B, TLC analysis was carried out on an aluminum-backed sheet of silica gel 60 F254 layer using ethyl acetate‒methanol‒ammonia (8:2:0.8, v/v) as the mobile phase. Quantification was carried out with UV detection at 262 nm. The validation of the proposed methods was applied according to the International Conference on Harmonization (ICH) guidelines. The suggested methods were successfully applied for the determination of the cited drugs in bulk powder and commercial dosage form.
Authors:V.-P. Lehto, K. Vähä-Heikkilä, J. Paski, and J. Salonen
Summary Thermally carbonised mesoporous silicon microparticles were produced and loaded with two active pharmaceutical ingredients, ibuprofen and antipyrine. By combining the results measured with TG and DSC, reliable estimations for the degrees of the drug loads were obtained. To distinguish the drug adsorbed on the surfaces of the microparticles from that absorbed into the pores, the principle of thermoporometry on the DSC measurements was employed. According to the principle, the drug held in the capillaries of porous material has a depressed melting temperature because of the higher pressure of the drug in cavities with a curved interface. On the other hand, the drug located on the external surface of the microparticles exhibits the normal melting of bulk drug. The loading degrees obtained with the thermoanalytical methods (31 and 26 mass& for ibuprofen and antipyrine, respectively) were comparable with the results obtained with helium pycnometry (the corresponding values were 33 and 28 mass&). Nitrogen sorption studies were not reliable for quantitative determinations due to the inability of nitrogen to penetrate in all pores, which might be blocked by the drug on the surface of the microparticles.
Authors:T. P. Shakhtshneider, M. A. Vasilchenko, A. A. Politov, and V. V. Boldyrev
The method of mechanical activation was used to obtain solid-state dispersions of some drugs in polyvinylpyrrolidone, polyethylene glycol and talc as carriers. Solid dispersions obtained by mechanical activation were found to have higher apparent solubilities and dissolution rates than mechanically activated drugs or their physical or eutectic mixtures with carriers used. It was shown by IR-spectroscopy and fluorescence measurements that mechanical treatment gave rise to an interaction between components which was apparently responsible for the solubilization effects observed.
Authors:K. Kafarska, D. Czakis-Sulikowska, and W. Wolf
New metal(II) complexes with empirical formulae Co(ibup)2·4H2O, Cd(ibup)2·3H2O, Co(nap)2·H2O, Cd(nap)2·3H2O (where ibup=(CH3)2CHCH2C6H4CH(CH3COO−) and nap=CH3O(C10H6)CH(CH3COO−)) were isolated and investigated. The complexes were characterized by elemental analysis, molar conductance, IR spectroscopy
and thermal decomposition. The thermal behavior was studied by TG, DTG, DTA methods under non-isothermal conditions in air
atmosphere. The hydrated complexes lose water molecules in first step. All complexes decompose via intermediate products to corresponding metal oxides CoO and CdO. A coupled TG-MS system was used to detect the principal
volatile products of thermolysis and fragmentation processes of Co(nap)2·H2O. The IR spectra of studied complexes revealed also absorption of the carboxylate group. Principal concern with the position
of asymmetric, symmetric frequencies. The value of their separation allow to deduce about type of coordination these groups.
]. In this study, FT-IR and/or thermal analysis using DSC was employed to study any interactions between grewia polysaccharide gum and the active pharmaceutical ingredients, cimetidine and ibuprofen. FT-IR spectroscopy provides a useful tool for the
Authors:Małgorzata Starek, Jan Krzek, and Marzena Stoch
A TLC-densitometric method has been established for identification and quantification of tiaprofenic acid, ketoprofen, naproxen, dexibuprofen, flurbiprofen, alminoprofen, and ibuprofen in selected pharmaceutical preparations. The separation was performed on TLC silica gel F
plates using two mobile phases. UV densitometry was performed at 225 and 270 nm. The method is of high sensitivity; limits of detection and quantitation range from 0.05 to 0.29 μg per band. For individual constituents recovery ranged from 98.71% to 102.65%.
Authors:G. Bannach, R. Arcaro, D. Ferroni, A. Siqueira, O. Treu-Filho, M. Ionashiro, and E. Schnitzler
Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction
powder (DRX) patterns and Fourier transformed infrared spectroscopy (FTIR) were used to study ketoprofen, ibuprofen, and naproxen.
The chemical or physical properties of the studied compounds were established and when possible by X-ray powder diffractometry
and/or infrared spectroscopy were used. In this investigation, quantum chemical approach was used to determine the molecular
structures using Becke three-parameter hybrid method and the Lee–Yang–Par (LYP) correlation functional. The performed molecular
calculations in this work were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FTIR
spectra supplying structural and physicochemical parameters.
Effects of the colour of curatives, of previous experiences and expectations, and of personality variables upon the generation of non-specific adverse (nocebo) effects of drugs were studied in a double-blind, randomized experiment. Thirty-eight female undergraduate students completed questionnaires (experiences, expectancies, state anxiety (STAI-S), dispositional optimism (LOT-R), somatosensory amplification (SSAS), somatic symptoms (PHQ-15)), then randomly ingested a white or red NSAID tablet (200-mg ibuprofen), and monitored themselves for 10 min for symptoms. According to a regression analysis, predictors of experienced symptoms were personal experiences with and expectations of side effects, and SSAS and PHQ-15 scores. Regarding the 14 monitored symptoms, significant differences between red and white tablets were found in five cases (irritability/agitation, palpitation vs. drowsiness, blurred vision, heartburn). Better understanding of personality and situational factors causing nocebo effects could help to identify and to avoid them.
Authors:Mieczysław Sajewicz, Robert Piętka, Gabriela Drabik, Ewa Namysło, and Teresa Kowalska
We have previously discussed in detail thin-layer chromatographic studies of the retention of the 2-arylpropionic acids (2-APA)
-(±)-2-phenylpropionic acid. Chiral TLC was performed on commercial silica gel layers impregnated with l
-arginine in the cationic form as chiral ion-pairing reagent. Retention and separation of the species was checked by densitometry.In this paper we report the striking skewed migration of these chiral APA in these TLC systems. Scanning of the chromatographic plates at 1-mm intervals revealed that the tracks of the
-(+) and the
-(−) APA can deviate markedly from the vertical in mutually opposite directions. This striking effect in the two-dimensional separation of the enantiomers is most probably caused by stereospecific intermolecular interactions which occur during ion-pair formation between l
-arginine in the cationic form, deposited on the silica gel layer as chiral selector, and each individual 2-APA in the anionic form.