Chromatographi 68 (1-2), 129-133 (2008). Description of a simple, rapid, specific and sensitive method for the quantitative estimation of mevalonic acid in leaves of Artemisia annua, Psorelia corylifolia, Vinca rosea, Withania somnifera and Barleria proinites. TLC of leaf extracts on silica gel with benzene - acetone 3:2 which involved conversion of mevalonic acid to its lactone, mevalonolactone. Detection by treatment with anisaldeyde reagent. Quantitative determination of mevalonolactone by absorbance measurement at 600 nm. Linearity was between 100 and 500 ng per spot. Recovery (by standard addition) was higher than 98 % for mevalonolactone. The limit of detection was 50 ng per spot.

Indian Drugs 45(4), 301-306 (2008). HPTLC of diclofenac (extracted with 3N HCl and chloroform from single and multi-component diclofenac gel formulations) on silica gel with toluene - ethyl acetate - acetic acid 600:400:2. The hRf value of diclofenac was 39, of salicylic acid 29, and of methyl salicylate 83. Quantitative determination by absorbance measurement at 283 nm. Linearity was between 200 and 600 ng/spot via peak area. In single component gel, recovery was 100.4 % whereas in multi-component gel it was 99.5 %. The method was found to be accurate and suitable for analysis in single and multi-component gel formulations.

60th Indian Pharmaceutical Congress PA-177, (2008). HPTLC of sibutramine hydrochloride on silica gel with benzene - methanol 9:1. Quantitative determination by absorbance measurement at 223 nm. The method was linear in the range of 2-22 µg/mL (UV-Visible) and 100-700 ng/spot (HPTLC). The recovery was 99.5-101.6 % for both methods. The proposed methods could be used for routine analysis of the drug in capsule dosage-form

Chromatographia 69 (1-2), 157-161 (2009). TLC of amlodipine besylate (AML) and valsartan (VAL) on silica gel with toluene - methanol - acetic acid 70:30:1. Quantification by absorbance measurement at 244 nm. Linearity was between 100 - 600 ng/spot for AML and 1600 - 9600 ng/spot for VAL. For AML the RSD of intra-day precision was 1.5 - 1.8 % and of inter-day precision 1.2 - 2.0 %. For VAL the RSD of intra-day precision was 0.1 - 0.4 % and of inter-day precision 0.2 - 0.5 %. Accuracy was 98.3 % for AML and 98.7 % for VAL.

CBS 101, 12-13 (2008). During a drug substance stability study a mass imbalance was discovered in light degraded samples. HPTLC on silica gel first with ethyl acetate - heptane, then, after drying, with tetrahydrofuran in a horizontal developing chamber. Detection under UV 254 nm and by densitometry at 240 nm. During another project differences in color between batches of a drug substance were observed. HPTLC on amino phase with methanol in a horizontal developing chamber. Detection under white light and under UV 366/>400 nm.

Asian J. Chem. 19(4), 2955-2960 (2007). TLC of esomeprazole and domperidone on silica gel with chloroform - acetonitrile - ammonia 20:40:1. Quantitative determination by absorbance measurement at 222 nm. The hRf value was 76 for esomeprazole and 89 for domperidone. Linearity was between 600 and 1400 µg/mL for domperidone and 1200 and 2800 µg/mL for esomeprazole. Recovery (by standard addition method) was 99.6 %. The proposed method is precise, accurate and can be used for routine analysis of esomeprazole and domperidone in tablets.

Asian J. Chem. 19(7), 5647-5651 (2007). HPTLC of levofloxacin hemihydrate and ornidazole on silica gel with n-butanol - water - acetic acid 3:1:1. Quantitative determination by absorbance measurement at 366 nm. The method was linear in the range of 1050-1400 µg/mL and 2600-2900 µg/mL for levofloxacin and ornidazole respectively. The recovery was between 97.3 and 98.0 % for both drugs. The method was suitable for simultaneous estimation of both drugs in combined tablet dosage form.

J. Chromatogr. A 1112 (1-2), 156-164 (2006). HPTLC of glucosamine in a dietary supplement containing dried extracts of the main plants traditionally used for rheumatic disorders, on silica gel with a saturated mixture of 2-propanol - ethyl acetate - ammonia (8 %) 1:1:1. Detection by dipping into a modified anisaldehyde reagent and heating at 120 °C for 30 min in a drying oven. Quantitative determination by absorbance measurement at 415 nm. Validation of the method by applying the novel validation protocol proposed by a commission of the Société Française des Sciences et Techniques Pharmaceutiques. Relative standard deviations for repeatability and intermediate precision were between 4.9 and 8.6 %, accuracy was good, the two-sided 95 % beta-expectation tolerance interval was within the acceptance limits of 85 and 115 % on the whole analytical range (800 - 1200 ng of glucosamine).