Małgorzata Starek

A review of analytical techniques for determination of oxicams, nimesulide and nabumetone.

Non-steroidal anti-inflammatory drugs (NSAIDs) are the group most often used in human health care, since they are available without prescription for treatment of fever and minor pain. The present review submitted the use of various analytical techniques for the determination of oxicams, nimesulide and nabumetone. This review covers the time period from 1990 to 2008 during which over 200 analytical methods including all types of chromatographic, spectrophotometric and voltammetric techniques were reported. Presented application concerns analysis of chosen NSAIDs from pharmaceutical formulations and biological samples.

Simultaneous identification and quantitative determination of neomycin sulfate, polymixin B sulfate, zinc bacytracin and methyl and propyl hydroxybenzoates in ophthalmic ointment by TLC

A thin layer chromatographic-densitometric method for identification and quantitation of neomycin sulfate, polymixin B sulfate, zinc bacytracin and auxiliary substances (methyl and propyl hydroxybenzoates) in ophthalmic ointment was developed. To separate these constituents the silica gel coated TLC plates and two mobile phases were used. The suitable mobile phases were: methanol-n-butanol-ammonia 25%-chloroform (14:4:9:12, v/v/v/v) for determination of antibiotics and n-pentane-glacial acetic acid (66:9, v/v) for methyl and propyl hydroxybenzoates. The antibiotic chromatograms were detected by using ninhydrin ethanol solution, while densitometric measurements were made at lambda = 550 nm. Hydroxybenzoates were identified by UV measurements at lambda = 260 nm. The constituents under consideration were well separated at sufficient detection level. The recovery for all constituents ranged from 98.08% to 104.95%.

Analytical approaches to determination of carnitine in biological materials, foods and dietary supplements.

l-Carnitine is a vitamin-like amino acid derivative, which is an essential factor in fatty acid metabolism as acyltransferase cofactor and in energy production processes, such as interconversion in the mechanisms of regulation of cetogenesis and termogenesis, and it is also used in the therapy of primary and secondary deficiency, and in other diseases. The determination of carnitine and acyl-carnitines can provide important information about inherited or acquired metabolic disorders, and for monitoring the biochemical effect of carnitine therapy. The endogenous carnitine pool in humans is maintained by biosynthesis and absorption of carnitine from the diet. Carnitine has one asymmetric carbon giving two stereoisomers d and l, but only the l form has a biological positive effect, thus chiral recognition of l-carnitine enantiomers is extremely important in biological, chemical and pharmaceutical sciences. In order to get more insight into carnitine metabolism and synthesis, a sensitive analysis for the determination of the concentration of free carnitine, carnitine esters and the carnitine precursors is required. Carnitine has been investigated in many biochemical, pharmacokinetic, metabolic and toxicokinetic studies and thus many analytical methods have been developed and published for the determination of carnitine in foods, dietary supplements, pharmaceutical formulations, biological tissues and body fluid. The analytical procedures presented in this review have been validated in terms of basic parameters (linearity, limit of detection, limit of quantitation, sensitivity, accuracy, and precision). This article presented the impact of different analytical techniques, and provides an overview of applications that address a diverse array of pharmaceutical and biological questions and samples.

Reversed-phase thin-layer chromatography technique for the comparison of the lipophilicity of selected non-steroidal anti-inflammatory drugs.

The chromatographic behavior of a series of coxibs and oxicams, drugs from a group of non-steroidal anti-inflammatory drugs, was studied by reversed-phase thin-layer chromatography with binary mobile phases containing water and the organic modifiers: methanol, acetone, 1,4-dioxane, acetonitrile and 2-propanol. Linear relationships were obtained between the retention RM values of the compounds and the concentration of organic modifier in the mobile phase. Values of RM0, represent the theoretical RM values at 0% organic solvent in the mobile phase were calculated by extrapolation. These experimental lipophilicity values were correlated with lipophilicity (logP) from databases. The obtained results show that reversed-phase chromatography (experimental parameters) may be a good instrument for analytics in describing the lipophilic nature of investigated compounds as well as the activity.

Lipophilicity study of some non-steroidal anti-inflammatory agents and cephalosporin antibiotics: A review

Lipophilicity properties have long been considered a vital component of drug discovery and development, providing insight into the role of molecular properties in the biological activity of known and new compounds. An extensive survey of the literature published in analytical and pharmaceutical chemistry journals has been conducted. Separation, optical, electrochemical and calculation methods which were developed and used for determination of lipophilicity non-steroidal anti-inflammatory agents and cephalosporin antibiotics in drugs and biological materials, have been reviewed. This review covers over 100 miscellaneous methods. Presented review highlighted some recent developments and new techniques that have been used in the lipophilicity detection of two different kinds of drugs.

Review of the applications of different analytical techniques for coxibs research.

An extensive survey of the literature published in analytical and pharmaceutical chemistry journals has been conducted and analytical methods which were developed and used for the determination of some of the COX-2 inhibitors, a subclass of non-steroidal anti-inflammatory drugs (NSAIDs) in bulk drugs, formulations, and biological fluids have been reviewed. This review covers the time period from 1999 to present, during which over 140 analytical procedures including chromatographic, spectrometric, electrophoretic and voltammetric techniques were reported. Presented applications concern analysis of coxibs from pharmaceutical formulations and biological samples.

TLC-densitometric analysis of β-sitosterol in pumpkin seed oil

A densitometric thin-layer chromatographic method has been established for quantitative determination of P-sitosterol in pumpkin seed oil (Cucurbita pepo L.). Chromatography was performed on silica gel 60 F254 TLC plates, with toluene-ethyl acetate-glacial acetic acid 15:4:1 (v/v) as mobile phase. Densitometric quantitation was performed at 525 nm. The method was validated by determination of linearity (15-750 μg mL-1), precision (RSD = 2.36%), and limits of detection (LOD = 0.65 μg per band) and quantification (LOQ = 1.99 μg per band). Average recovery from the pharmaceutical preparation was 96.15%. The method enables simple, rapid, and precise quantitative determination of P-sitosterol in pharmaceutical preparations and can be used for routine quality control.

Densitometric Determination of Naproxen, and of Naproxen Methyl Ester, its Impurity, in Pharmaceutical Preparations

A chromatographic–densitometric method has been established for identification and quantification of S-(+)-2-(6-methoxy-2-naphthyl) propionic acid (S-(+)-naproxen) and naproxen methyl ester in pharmaceutical preparations. The chromatographic separation was performed on silica gel F254 TLC plates with cyclohexane–chloroform–methanol, 12 + 6 + 1 (v/v), as mobile phase. UV densitometric detection was performed at λ = 223 nm. The method is highly sensitive; the limit of detection for naproxen is 30 ng. Recovery was satisfactory at 95.4%, response was linearly dependent on quantity over a wide range, from 0.0015% to 0.0060%, and repeatability was also satisfactory. The effect of pH, temperature, and incubation time on the degradation of naproxen was investigated.

Simultaneous identification and quantitative analysis of eight cephalosporins in pharmaceutical formulations by TLC-densitometry

A rapid, accurate, and sensitive densitometric TLC method has been established and validated for simultaneous analysis of eight β-lactam antibiotics (cephalexin, cefadroxil, and cefazolin (first-generation), cefaclor, cefuroxime, and cefuroxime axetil (second-generation), and ceftriaxone and cefotaxime (third-generation)). Chromatographic separation was achieved on silica gel F254 plates with chloroform-ethyl acetate-glacial acetic acid-water 4:4:4:1 (v/v) as mobile phase. Densitometric detection was performed at 275 nm. Statistical evaluation showed the performance of the method was satisfactory. Accuracy was in the range 98.30–100.85% and precision, as RSD, was from 0.4 to 2.45%.

Densitometric Analysis of Celecoxib, Etoricoxib and Valdecoxib in Pharmaceutical Preparations

A densitometric thin-layer chromatographic method has been established for the analysis of celecoxib, etoricoxib, and valdecoxib in pharmaceutical formulations. TLC was performed on silica gel 60 F254 plates with chloroform-acetone-toluene 12:5:2 (v/v) as mobile phase. UV detection was performed by densitometric scanning at 254 and 290 nm. The method was validated by determination of linearity, precision, limits of detection, and determination (from 0.0017 to 0.0848 μg per band) and accuracy (from 99.16 to 100.48%).