Indian Journal of Pharmaceutical Sciences 66 (1), 132-135, 2004. HPTLC of bacoside A in Bacopa monnieri and in its commercial monoherbal capsule formulation on silica gel 60 F254 aluminium sheet, 20 x 10 cm, with chloroform - methanol - water 30:15:1. Quantification by densitometry at 540 nm via linear regression in the range of 30 -180 µg/mL. Rf of Bacoside A was found to be 0.51. Validation regarding to accuracy, precision, specificity and recovery (97.4 – 100.1%). The proposed simple and sensitive method provides faster and cost effective qualitative control for routine analysis of bacoside A in formulations containing Bacopa monnieri saponins.

J. Liq. Chrom. Rel. Technol. 27, 2071-2085 (2004). HPTLC of enrofloxacin and ciprofloxacin on silica gel using dichloromethane - methanol - 2-propanol - 25 % ammonia 3:3:5:2. Bioautography with Chrom Biodip® Antibiotics Test Kit. The developed and dried plate was immersed briefly in the microorganism solution and incubated overnight at 28 °C. After incubation the plate was sprayed with 3-[4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-solution and incubated for about 30 min. The dried plates were scanned for documentation. The areas of the inhibition zones were then measured with a planimeter.

J. Planar Chromatogr. 17, 464-467 (2004). Displacement chromatography (DC) has been widely used to separate metabolites with similar chemical characteristics. DC works with highly overloaded sample sizes, which are normal for samples not subjected to clean-up. DC successfully handels samples which contain high concentrations of salts and/or proteins, and results in consecutive steps of displaced compounds rather than Gaussian curves. Planar displacement chromatography (DTLC) is suitable for seeking new metabolites in excreted body fluids. Transfer of the radiolabeled methyl group can easily be proven using spacer-displacement planar chromatography. Displacement TLC of L-deprenyl and 14C-L-deprenyl on silica gel with chloroform - triethanolamine 19:1. Detection by X-ray film with an exposure time of 120 h.

Densitometric determination of mexiletine hydrochloride in capsules. J. Planar Chromatogr. 17, 213-217 (2004). TLC of disopyramide, flecainide, mexiletine, tocainide, and verapamil on aluminium oxide and silica gel in horizontal chambers. The best mobile phase for separation on the alumina plates was tetrahydrofuran - hexane - 25 % ammonia 25:24:1 and on silica chloroform - tetrahydrofuran - ethanol - 25 % ammonia 81:19:20:1. Detection under UV light at 210 nm and by use of different reagents. Quantification of mexiletine hydrochloride in capsules was performed densitometrically at 254 nm.Correlation coefficient in the concentration range 20 - 45 µg per band was 0.9974, with RSD of 5.23 %.

J. AOAC Int. 88, 1537-1543 (2005). HPTLC of caffeine, acetaminophen and acetylsalicylic acid on silica gel with concentration zones using methanol - ethyl acetate 3:17. UV absorption densitometry is used for the quantitative determination of caffeine. Precision, accuracy, linearity, limits of detection and quantitation, and selectivity were validated. - A comparative study using a caffeine standard solution and a multicomponent analgesic tablet solution containing caffeine, acetaminophen, and acetylsalicylic acid showed that manual application on the concentration zone, and instrumental application on the silica gel gave quite similar results in terms of number of theoretical plates, resolution, limit of detection, and linearity.

J. Planar Chromatogr. 18, 326-329 (2005). HPTLC of levonorgestrel on silica gel (prewashed with chloroform - methanol 1:1 and once with the mobile phase, dried and activated at 100 °C for 15 min) with toluene - 2-propanol 9:1 in an automatic multiple development chamber without chamber saturation. Visual examination under UV light at 254 nm; quantitation by densitometry at 250 nm.

J. Planar Chromatogr. 18, 98-103 (2005). Salting-out TLC (SO TLC) of five ACE inhibitors and their active degradation products (enalapril, enalaprilat, quinapril, quinaprilat, fosinopril, fosinoprilat, lisinopril, cilazapril, cilazaprilat) on silica gel, cellulose, and polyacrylonitrile with aqueous ammonium sulfate solutions of different concentrations. Increasing the salt concentration in the mobile phase led to increased RM values for all substances. For comparison TLC on RP-18 with methanol - water. Detection by exposure to iodine vapour.

Indian Drugs 42 (12), 805-807 (2005). HPTLC of alprazolam and sertraline in tablet dosage form on silica gel with toluene - ethyl acetate - methanol - acetic acid 90:30:20:3 without saturation. Quantitative determination by absorbance measurement at 217 nm. Accuracy, precision, and linearity were established. The linearity range was 20-100 ng for alprazolam and 100-500 ng for sertraline. Recovery rates were between 99.8-100.5 % for both drugs.