J. Pharm. Biomed. Anal. 36, 33-41 (2004). A sensitive selective, precise and robust HPTLC method for the analysis of E and Z stereoisomers of guggulsterone (the hypolipidemic agent in the gum-resin exudates of Commiphora mukul) both as a bulk drug and in formulations was developed and validated. Separation on silica gel with toluene - acetone 9:1. Quantitative determination by absorbance measurement at 250 nm. This system was found to give compact spots for E- and Z-guggulsterone (Rf value of 0.38 ± 0.02 and 0.46 ± 0.02 respectively) following double development with the same mobile phase. Both E- and Z-guggulsterone showed good linearity in the concentration range of 100-6000 ng/spot. The method was validated for precision, robustness, recovery, and specificity. The proposed HPTLC method is suitable for the identification and quantitation of these isomers in herbal extracts and pharmaceutical dosage forms.

IPC 56th 2004, Abstract No. G-20. Simultaneous HPTLC determination of loratadine and ambroxol in combined dosage form on silica gel with n-hexane - dichloromethane - triethanolamine 11:8:1.The Rf value of loratadine and ambroxal was found to be 0.40 and 0.16 respectively. Quantitative evaluation by scanning at 254 nm.The method was linear in the range of 0.2 -1 mg/spot for loratadine and 1.2 - 6 mg/spot for ambroxol with recovery of 98.2 - 98.5 %. The method was validated for accuracy, precision, linearity, specificity, LOD, and LOQ.

J. Planar Chromatogr. 18, 251-252 (2005). TLC of 22 silylated amino acids on silica gel with butanol. After spotting the plates with the amino acid solutions the samples were sprayed with hexamethyldisilazane reagent (1 % solution in acetone), dried, heated at 110 °C for 20 min, and cooled. The developed plates were dried, sprayed with ninhydrin (0.25 % solution in acetone), dried completely, then further heated at 110 °C for 20 min. Detection limits of this method within 10 min are comparable with those of other methods.

J. Sep. Sci. 30, 1250-1254 (2007). HPTLC of Emblica officinalis extract on silica gel with ethyl acetate – formic acid – glacial acetic acid – water 10:1:1:2. Primary detection under UV 280 nm. Antiradical activity of individual components was estimated on intensity of disappearance of violet/purple background of plate after dipping in DPPH radical solution (0.5 mM in methanol) at room temperature for 90 s and that 30 s at 60 °C. Quantitative determination by absorbance measurement at 517 nm as negative peak. DPPH radical scavenging activity of emblicanins A and B was 7.9 and 11.2 times more active than that of ascorbic acid and 1.3 and 1.8 times more active than gallic acid, respectively.

Biomed. Chromatogr. 21 (1), 94-100 (2006). Presentation of a post TLC developing technique to detect substances which can inhibit tyrosinase activity. The TLC plate is sprayed with tyrosinase and l-tyrosine solutions successively. A positive result is detected as white zone against a brownish-purple background. The method is suitable as a quick screening procedure for tyrosinase inhibitor detection, and as a guiding procedure for the isolation of tyrosinase inhibitors from mixtures or natural product extracts.

Science & Culture Jan.-Feb., 22-30 (2008). Isolation and identification of some unique chemical compounds is reported using chemical, chromatographic and spectroscopic methods such as GC-MS, HPTLC and HPLC. The presence of bio-organic molecules such as oxygenated dibenzo-a-pyrones (DBPs), their amino acyl conjugates (DCPs) and polyphenyl benzoquinones (PBQs) was observed in all the four samples of meteorites. HPTLC on silica gel with 1) n-butanol - acetone - acetic acid - water 7:7:2:4 for amino acids, detection with ninhydrine reagent and absorbance measurement at 610 nm; 2) n-butanol - acetic acid - water 3:1:2 for sugars, detection with p-anisidine reagent and absorbance measurement at 380 nm; 3) chloroform - methanol 9:1 for DBPs and absorbance measurement at 240 nm and 360 nm.

Abstract No. 9185, IHCB (2009). HPTLC of hydro alcoholic extracts of Berberis aristata on silica gel with benzene - ethyl acetate - diethyl amine 6:3:1. Detection by spraying with AlCl3 reagent (for estimation of flavonoids) or with Folin Ciocalteu reagent (for total phenolic content). The fingerprint profile was optimized using two different mobile phases: n-butanol - acetic acid - water 14:1:5 and n-propanol - formic acid - water 90:1:9. The extract showed 6 different spots and was found to contain 13.5 % w/w of berberin.

Rec. Nat. Prod. 3/4, 178-186 (2009). An HPTLC method has been reported for quantitative estimation of alpha-mangostin in fruit pericarp of Garcinia mangostana (Hypericaceae). HPTLC on silica gel with chloroform - methanol 9:1 in a saturated chamber (10 min). The plate was derivatized with anisaldehyde sulfuric acid reagent. Densitometric quantification at 382 nm. Alpha-mangostin was detected as a compact band with hRf value of 46. The method was linear in the range of 1-5 µg/band. The maximum yield of alpha-mangostin was obtained from the plant by hot extraction with methanol.