IPC 56th 2004, Abstract No. GP-11. Stability indicating HPTLC determination of indapamide in tablets on silica gel with toluene - methanol 7:3. Quantitative determination by scanning at 246 nm. Optimization of experimental parameter such as band size, chamber saturation, and slit width. The method was linear in the range of 1.4 - 3.72 g, recovery was 100.01 %. The drug was subjected to stress conditions according to ICH guidelines, degradation products were separated from the pure drug. The method was validated for accuracy, precision, linearity, and specificity.

J. Planar Chromatogr. 19, 4-9 (2006). TLC and HPTLC of 2-thioguanidine and 6-mercaptopurine on silica gel with methanol in a horizontal DS-chamber. Spots were visualized with a freshly prepared solution of sodium azide and starch, adjusted to a pH within the range 5.5-6.0, and then exposed to iodine vapor. The thiols became visible as white spots on a violet-gray background. The iodine-azide reagent enabled detection of quantities in the range 1-80 pmol per spot.

Indian Drugs 42 (7), 465-468 (2005). HPTLC of tizanidine and diclofenac in tablet formulations on silica gel with chloroform - methanol 4:1. Quantitative determination by absorbance measurement at 230 nm. Cetrizine was used as an internal standard. The solvent system was found to give compact spots for diclofenac sodium (Rf value 0.86), tizanidine (0.26) and cetrizine (0.52). The method was validated for linearity, accuracy and precision. Linearity for tizanidine was 0.6-1.4 µg/mL, and for diclofenac sodium 7.5-17.5 µg/mL . The mean recoveries obtained for tizanidine and diclofenac sodium were 98.73 % and 99.70 %, respectively. The proposed method was accurate, precise, selective and rapid for simultaneous estimation of tizanidine and diclofenac sodium in tablets.

Acta Chrom. 13, 154-160 (2003). Samples of nicotine were exposed to air and UV light and the products formed (nicotyrine, cotinine, and trans-3'-hydroxycotinine) were separated by TLC on RP-18 with acetonitrile – water 22:3 in a horizontal chamber. Visual evaluation under UV 254 nm, and under white light after derivatization with Dragendorff’s reagent. Quantitative determination by absorbance measurement at 260 nm. GC–MS analysis was performed to confirm the identities of the nicotine transformation products.

iNDIAN dRUGs 44(8), 632 (2007). TLC, HPTLC and NMR spectroscopic methods are reported for identification and characterization of aloin isolated from Kumariasava and Aloe vera. TLC and HPTLC of chloroform extracts on silica gel with chloroform - ethyl acetate 3:1. Detection under UV 366 nm. The hRf value of aloin was 84.

J. Sep. Sci. 31, 71-77 (2008). HPTLC of acrylamide in drinking water on silica gel, derivatization in situ with 5-dimethylamino-naphtalene-1-sulfinic acid (1.6 µg/µL in methanol), followed by heating at 120 °C for 1 hour and developed with ethyl acetate. For fluorescence enhacement, the plate was dipped into a solution of 25 % polypropylene glycol in n-hexane and dried immediately. Quantitative determination by fluorescence at 366/>400 nm. Verification was based on HPTLC-ESI/MS, HPTLC-direct analysis in real time (DART)-TOF/MS and NMR. The hRf value of acrylamide (as 3-dansylpropanamide) was 69. Linearity was between 0.1 and 0.4 µg/L. Within-run precision and the mean between-run precision (n=3) were 4.6 and 11.0 %. The limit of detection and quantification for acrylamide was 0.025 and 0.083 µg/L, respectively. Recovery (by standard addition) was 96.4 %. The method showed comparable result with HPLC-MS/MS.

J. Agric. Food Chem. 56, 4311-4319 (2008). HPTLC of the heterocyclic aromatic amines (HAA) most frequently found in fried meat: 2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazol[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 9H-pyrido[3,4-b]indole (norharman), and 1-methyl-9H-pyrido[3,4-b]indole (harman) using a previously validated method. Concentrations obtained by HPTLC were in a similar range as such obtained by HPLC with correlations of both methods between 0.8875 and 0.9751. The precision in meat matrix was between 7 and 49 % (HPTLC) and between 5 and 38 % (HPLC) at the very low µg/kg-levels formed during heating. Cost and time comparison showed that HPTLC is 4 times faster and 3 times less expensive than the HPLC reference method.

Talanta 78 (3), 874-884 (2009). Presentation of a sensitive, selective and precise stability-indicating method for the determination of clopidogrel bisulfate in presence of its alkaline degradate and in pharmaceutical formulations. TLC on silica gel with hexane – methanol - ethyl acetate 87:10:3. Quantification by densitometry at 248 nm in the range of 0.6–3 µg/band. Recovery was 99.9 %. Clopidogrel could be determined in the presence of up to 90 % of its alkaline degradate. Method selectivity was evaluated using laboratory prepared mixtures. The analysis of clopidogrel in pharmaceutical dosage forms is possible without interference from additives.