A hybrid adsorbent/visible light photocatalyst for the abatement of microcystin-LR in water.

A hybrid adsorbent/photocatalyst was obtained and used for the removal of microcystin-LR, a potent toxin, from water via adsorption and photocatalyzed oxidation with singlet oxygen. The combined adsorption/photooxidation processes yielded a 500-fold decrease of the overall MC-LR concentration. The adsorbent/photocatalyst can be easily removed from the reaction system by sedimentation or centrifugation.

Chromatographic and electrophoretic techniques used in the analysis of triazole antifungal agents-a review.

Systematic review of literature coupled with integrative research of published data for triazole antifungal agents was done. The investigated literature covered chromatographic and electrophoretic methods developed in the last 10 years (2000-2009). The aim of this review was to compare different methodologies, assess preferences in the selection of analytical methods and to find still existing analytical problems. Last decade is characterized by dynamic development of instrumental methods, that results in advance and diversity of applied analytical procedures. The main focus was given to high-performance liquid chromatography (HPLC), the technique of choice in the analysis of most of pharmaceuticals. The review includes literature on 8 triazole antifungal drugs: fluconazole, itraconazole and terconazole from the first generation and posaconazole, voriconazole, ravuconazole, isavuconazole and albaconazole classified in second generation. Investigations of pharmaceutical formulations and biological samples were considered.

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%.

Densitometric analysis of kawain in kava-kava root extracts.

A thin layer chromatographic-densitometric method for the identification and determination of kawain in a mixture of kavalactones obtained from a methanol extract of kava-kava roots (Piper methysticum) was developed. The main compounds present in the extract were separated with good results using silica gel F 254 coated TLC plates as the stationary phase and hexane-dioxane-butyl acetate-ammonia 25% (7:2:3:0.5 v/v/v/v) as the mobile phase. The qualitative identification and quantitative measurement of kawain were obtained by UV measurements at lambda=250 nm. The described method demonstrates very high sensitivity with the limit of detection established at 20 ng. 99.38% of the kawain was recovered and the concentration range showed a linearity from 0.0005% to 0.004%. Under these conditions, the percent of kawain in the presence of other kavalactones in the prepared extracts (I-VII), was determined. Similar results were obtained for all extracts, with the kawain content ranging from 1.01% to 1.16%.

Determination of gliclazide in pharmaceutical preparations by capillary gas chromatography with cool on-column injection and elimination of the matrix effect.

Conditions were established for the identification and quantitation of gliclazide in pharmaceutical preparations by capillary gas chromatography with flame ionization detection and cool on-column injection. Gliclazide was extracted with methanol and, after filtration, assayed on a (25 m x 0.25 mm id, 0.2 microm film thickness) CP-WAX 58 (FFAP)-CB WCOT fused silica column. Because the available preparations were of various origins and, therefore, could differ in auxiliary substances and their qualitative parameters, the influence of the matrix constituents on the analytical results was taken into account. Good separation conditions were established for the developed method. The retention time of gliclazide is about 36 min and differs from the retention times of the internal standard (approximately 29 min) and additional peaks present in chromatograms (20-26 min), which were assigned to matrix constituents. The recoveries of gliclozide were high and reached 96.5%. The developed method is characterized by selectivity and precision (relative standard deviation 0.38-1.26%), a wide range of linearity (0.1-10.0 mg/mL), and a limit of detection of 30 ng. In addition, the results of chromatographic analyses calculated in 3 ways were compared with those obtained by UV spectrophotometry. The suggested technique of cool on-column injection, in contrast with split-splitless injection (used in preliminary investigations), reduces to a minimum the possibility of thermal decomposition of gliclazide.

Simultaneous densitometric determination of indomethacin and its degradation products, 4-chlorobenzoic acid and 5-methoxy-2-methyl-3-indoleacetic acid, in pharmaceutical preparations.

A densitometric method was developed for the identification and determination of indomethacin and its degradation products, 4-chlorobenzoic acid and 5-methoxy-2-methyl-3-indoleacetic acid, in pharmaceuticals. To separate these compounds, silica gel-coated thin-layer chromatography plates and the following mobile phase were used: 2-propanol-25% ammonia-water (8 + 1 + 1, v/v). UV densitometric measurements were made by comparing the absorption spectra and Rf values of appropriate standards with the pharmaceutical preparations examined. The conditions for separation were established and a low detection limit was obtained. Average recoveries were 100.69, 90.09, and 91.17% for indomethacin, 4-chlorobeznzoic acid, and 5-methoxy-2-methyl-3-indoleacetic acid, respectively.

Identification and determination of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations by thin-layer chromatography/densitometry.

A thin-layer chromatographic/densitometric method was developed for the identification and quantitation of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations. Silica gel-coated thin layer chromatography plates and 2 mobile phases were used to separate these constituents. The appropriate compositions of the suitable mobile phases were established: 10% citric acid solution-n-hexane-ethanol (80 + 1 + 1, v/v) and n-butanol-ethanol-chloroform-25% ammonia (4 + 5 + 2 + 5, v/v). Along with Rf values and spot colors, direct UV and visual densitometric measurements were used for identification. Similar measuring ranges were used for quantitative analysis to obtain repeatable and reliable results for the preparations examined. The results of the quantitative analysis are characterized by a small confidence interval and are close to the declared contents of active constituents: oxytetracycline 30.01 +/- 0.38 g at lambda = 350 nm and 30.24 +/- 0.86 g at lambda = 430 nm; tiamulin, 10.19 +/- 0.86 g at lambda = 450 nm; lincomycin, 2.27 +/- 0.08 g at lambda = 278 nm; and spectinomycin, 2.18 +/- 0.07 g at lambda = 421 nm. The recoveries for all antibiotics ranged from 100.01 to 102.54%.

Densitometric determination of impurities in pharmaceuticals. Part VI. Determination of 4,4-bis[4-(p-chlorophenyl)- 4-hydroxypiperidino]butyrophenone in haloperidol.

A chromatographic and densitometic method for identification and quantitative determination of 4,4-bis[4-(p-chlorophenyl)-4-hydroxypiperidino]butyrophenone as an impurity in haloperidol pharmaceutical has been developed. The HPTLC plates and chloroform-methanol-ammonium hydroxide 25% (90:9:1) were used for chromatographic separation as stationary and mobile phases respectively. Detection has been carried out in UV at lambda = 350 nm. The determination could be made directly without preliminary component separation by extraction. Based on the statistical analysis of obtained results, it was found that the new method is accurate and repeatable.