CBS 81, 10-12 (1998). A number of applications of HPTLC in the bulk drug industry are presented: process optimization, fermentation process monitoring, impurity profile, vessel residue certification and bulk drug analysis. The technique is advantageous when a large number of similar samples is to be analyzed and time and cost considerations are of importance.

CBS 91, 2-4 (2003). HPTLC on silica gel with dichloromethane - methanol 93:7 over 50 mm after preconditioning for 10 min. Quantitative determination by absorbance measurement at 274 nm. Repeatability is better than 3.5 % and intermediate precision better than 5.1 %.

CBS 90, 10-11 (2003). HPTLC of periwinkle cell samples on prewashed silica gel with ethylacetate - diethylamine 9:1 in horizontal developing chamber over 25 mm. Detection by radiation with short-wave UV 254 nm. Quantitative determination by fluorescence measurement at 254 nm or 365 nm.

J. Chinese Trad. Patent Med. (Zhongchengyao) 25 (7), 543-546 (2004). TLC on silica gel with 1) ethyl acetate - methanol - formic acid - water 10:1:1:1; 2) petroleum ether - chloroform - ethyl acetate - conc. ammonia 80:15:5:1; 3) chloroform - ethyl acetate - methanol - formic acid 35:10:5:1; 4) chloroform - ethyl acetate - methanol - formic acid 70:8:20:3; 5) chloroform - methanol - water 13:6:2. Detection 1) by spraying with 10 % H2SO4 in ethanol and heating at 105 ºC; 2) under UV 254 nm; 3) by spraying with 5 % vanillin - H2SO4 solution and heating at 105 ºC. Identification by finger print technique. Quantification of astragaloside by densitometry at 530 nm.

J. Chinese Trad. Patent Med. (Zhongchengyao) 26 (1), 23-26 (2004). TLC on silica gel with 1) chloroform - methanol - water 28:10:1, 2) n-hexane - ethyl acetate 9:1, 3) chloroform - methanol 5:1, 4) petroleum ether - diethyl ether 1:1. Detection 1) under UV 365 nm, 2) by spraying with 5 % vanillin in H2SO4 solution. Identification by fingerprint techniques. Quantitative determination of puerarin by HPLC.

CBS 93, 10-12 (2004). HPTLC of progesterone on silica gel prewashed by development in AMD2 first with chloroform - methanol 1:1 and then with the mobile phase, followed by drying at 80 °C for 15 min. Development in AMD2 with toluene - 2-propanol 10:1 without preconditioning over 60 mm. Quantitative determination by absorbance measurement at 252 nm followed by spectra recording from 200 to 360 nm. The linear working range is 25.7-154.5 ng/zone. Repeatability (standard deviation calculated from the amounts of seven simulated progesterone samples determined on the same plate at three concentration levels in the lower, middle and upper range) is 0.26-1.29 %. Recovery is 99.88-100.97 %. Reproducibility was performed with recycled HPTLC plates.

J. Planar Chromatogr. 17, 137-142 (2004). TLC of naproxen in pharmaceutical preparations (Naprosyn, Apranax, Aleve, Naproxen) on silica gel with cyclohexane - chloroform - methanol 12:6:1. Quantitative determination at 223 nm. Limit of detection for naproxen is 30 ng. Recovery and repeatability were satisfactory.

J. Planar Chromatogr. 17, 46-50 (2004). Two-dimensional TLC and HPTLC of cephalosporins (cefaclor, cefaperazone sodium, cefazolin sodium, cefotaxime sodium, cefoxitin sodium, cefuroxime sodium, cephalothin sodium, p-chlorophenacyl cephalotin ester) on silica gel in a horizontal chamber with methanol - 98 % formic acid - ethyl acetate 29:1:70 in the first dimension followed by methanol - toluene - ethyl acetate - 98 % formic acid 1:4:13:2 in the second dimension after drying for 1 h . Detection under UV light at 254 and 366 nm. Quantitative determination at 240 nm.