IPC 56th 2004, Abstract No. GP-26. HPTLC of triphala, an ayurvedic formulation containing about 3.60 % of total phenolics. Separation of alcoholic triphala extracts on silica gel with n-hexane - ethyl acetate 2:1. Rf value of the main spot gallic acid was 0.04 in triphala and its formulation. The method was found to be very specific for gallic acid having a linearity range of 0.2 - 1.6 mg/mL. Several formulations analyzed by HPTLC contained 5.2 - 7.6 % of gallic acid. The reported method is suitable for estimation of gallic acid in raw material and formulations.

Abstract G-28, IPC (2005). HPTLC of rosuvastatin on silica gel with chloroform - methanol - toluene 3:1:1. Quantitative determination by absorbance measurement. The hRf value of rosuvastatin was 53, recovery rate was between 98-102 %, LOD was 8 ng/spot and LOQ 26 ng/spot.

Abstract G-19, IPC (2005). HPTLC for estimation of corticosterone in rat plasma on silica gel with chloroform - methanol - water 9:10:1. Quantitative determination by absorbance measurement at 245 nm. Betamethasone was employed as internal standard. The extraction of plasma with ethyl acetate gave an average recovery of >85 %. The linearity was within the range of 30-300 ng/mL with LOQ being 30 ng. The method was found to be rugged and robust.

J. Pharm. Biomed. Anal. 39, 801-804 (2005). HPTLC on silica gel with chloroform - methanol 9:1. Quantitative determination by absorbance measurement at 265 nm. The hRf values of stavudine (SV), lamivudine (LV) and nevirapine (NV) were 25, 67 and 87 respectively. The method was linear within the range of 0.01-0.06 mg/mL, 0.05-0.30 mg/mL and 0.06-0.40 mg/mL for SV, LV, and NV respectively, recovery rates were between 98.2 and 99.9 %. The HPTLC method was compared with the UV and HPLC methods. Accuracy, precision and ruggedness of the method were established.

Abstract GP-55, IPC (2005). HPTLC of methanolic extracts of ambroxol and cetirizine combination tablets, on silica gel with methanol - ethyl acetate - toluene - ammonia 40:15:56:10 drops of ammonia. Quantitative determination by absorbance measurement at 231 nm. Rf values of cetirizine was 0.40 and of ambroxol 0.78, linearity range was 0.4-0.8 µg for cetirizine and 4-10 µg for ambroxol. Recovery was 99.3-100.4 % for both compounds. In comparison with a spectrophotometric method the HPTLC method had the advantage of higher throughput.

L. Planar Chromatogr. 19, 135-138 (2006). HPTLC of nitrendipine on silica gel with n-hexane - ethyl acetate - acetone 6:3:2 in a horizontal chamber. Visualization under UV light. Densitometry was performed in absorbance mode at 335 nm. The calibration plot was constructed in the range 0.025 to 0.150 µg/µL (corresponding to 0.5-3.0 µg/spot) with good correlation (r2> 0.990). The method is also characterized by good precision and accuracy.

J. Planar Chromatogr. 19, 241-245 (2006). TLC of the enantiomers of the beta-blockers (+/-)-propanolol, (+/-)-metoprolol, and (+/-)-atenolol on silica gel impregnated with a Cu(II)-L-arginine complex in a glass chamber saturated for 20-25 min using different mixtures of acetonitrile, methanol, and water as mobile phases. Impregnated TLC plates were prepared by spreading a slurry of 50 g silica gel in a solution of 100 mL of the Cu(II)-L-arginine complex and activating the plates overnight at 60 °C. The Cu(II)-L-arginine complex was prepared by mixing 1 mM copper(II) acetate and 2 mM L-arginine in water - methanol 9:1 and adjusting the final pH to 6-7 with aqueous ammonia. Detection with iodine vapor. Successful separation of all three racemic drugs was achieved with acetonitrile - methanol - water 15:2:2 and 15:2:1.

Acta Chrom. 13, 109-116 (2003). HPTLC of the laxative bisacodyl in enteric-coated tablets on silica gel with concentrating zone and 19 channels, pre-cleaned with dichloromethane – methanol 1:1, with ethyl acetate–methanol–glacial acetic acid 17:2:1. Quantitative determinaion by absorbance measurement at 254 nm. The method was validated and can be used for routine analysis of the pharmaceutical preparation in industry quality control and regulatory laboratories. An alternative extraction procedure and mobile phase are suggested for analysis of bisacodyl tablets with different formulations.