J. of China Pharm. 23 (20), 38-40 (2014). Nicotine is a toxic substance in tobacco. Studies have shown that nicotine may prevent and treat Alzheimer's disease (AD) and Parkinson's syndrome (PD). At present, the most effective method to treat AD is by inhibiting the activity of acetylcholinesterase (AChE), thus enhancing the cholinergic activity indirectly. In order to clarify the mechanism of nicotine reducing the incidence of AD, the activity of natural AChE inhibitors in Xinjiang Mohe tobacco was screened by TLC on silica gel with (A) ethyl acetate – methanol – ammonium hydroxide 70:30:1, followed by detection via enzyme inhibition (this is not bioautography, as stated in the title): firstly by spraying with 1.0 U/mL AChE (AChE 500 U + tris-HCl buffer solution of pH 7.8 500 mL + bovine serum albumin 500 mg), followed with 1.5 g/L alpha-naphthyl acetate (150 mg in ethanol 40 mL + water 60 mL) and then with 0.5 g/L Fast blue B salt, resulting in white zones on purple background; (B) toluene – ethyl acetate - diethylamine 7:2:1, detection by spraying with 0.2 mmol/L 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical reagent, resulting in white to yellow zones on pale purple background. The results indicated that nicotine in Xinjiang Mohe tobacco could bind to AChE and thus inhibit its activity.

GIT Fachz. Lab. 12, 1221-1223 (1986). Neue wasserbenetzbare HPTLC RP-18 Fertigplatten. New HPTLC RP-18 pre-coated plates wettable by water.) Description of a new HPTLC precoated plate based on silica gel with a reduced degree of modification with octadecyl groups. This plate material is fully wettable with methanol - water mixtures between 0:100 and 100:0. Running times for 50 mm are between 14 and 40 minutes, whereby the maximum running times occur with the 50:50 mixture. Separations of nicotinic acid - isonicotinic acid, of analgesics and of alkaloids.

J. of Medicinal Chemistry 32, 2432- 3435 (1989). TLC of vasotocin analogues on silica with butanol - pyridine - acetone water 15:10:3:6 or 15:10:3:12 and butanol acetic acid - water 4:1:1. Detection by exposure to chlorine followed by spraying with 1% aqueous KI-starch solution.

Proc. 6th Int. Symp. Instrum. Planar Chromatogr., (Interlaken 1991), Inst. Chromatogr., Bad Dürkheim, FRG, 401-408 (1991). Preliminary results are described for the combination of off-line TLC-FAB-MS for polar, ionisable compounds and their conjugated metabolites. HPTLC of benzoic acid, hippuric acid, phenolphthalein and its gucuronide, nitrophenol and its glucuronide and paracetamol and its sulfate on silica with chloroform - ethanol 3:2. Separated substances were removed and determinated by FAB-MS and MS-MS.

Arzneim.-Forsch./Drug Res. 45, 766-770 (1995). TLC of efonidipine hydrochloride (2-benzyl(phenyl)amino)ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-4-(3-nitrophenyl)-3-pyridinecarboxylate hydrochloride ethanol) and metabolites on silica with chloroform - methanol - diethylamine 18:1:1 or chloroform - methanol 1:1. Detection under UV 254 nm.

J. Planar Chromatogr. 11, 394-399 (1998). A new simple and powerful technique, on-line sample collection after high-resolution step-wise gradient OPLC separation combined with digital autoradiography (DAR) has been used for isolation of plasma and urine metabolites of 3H- or 14C-radiolabeled deramciclane (a new anxiolytic compound). This highly efficient separation can be followed by different MS techniques (FAB-MS, FAB-MS-MS, HPLC-MS, and HPLC-MS-MS) for determination of the structures of minor and major metabolites in different biological matrices. The combination of these methods resulted in a simple, sensitive, and efficient technique for metabolite research. OPLC on HPTLC silica gel, prewashed with methanol - water 4:1 with A) chloroform - acetonitrile 3:2 and B) n-butanol - acetic acid - water 4:1:1 for the gradient. Detection by digital autoradiography.

59th Indian Pharmaceutical congress F-225, 443, (2007). HPTLC cinnamaldehyde in the bark powder of Cinnamomum zeylenicum on silica gel with toluene - ethyl acetate - formic acid 190:10:1. Densitometric evaluation at 295 nm for quantification. The method was linear within the range of 31 and 157 ng/zone. The identity of the compound was confirmed by over overlaying the UV spectra of sample and standard. Cinnamomum bark was found to contain 0.25 % of cinnamaldehyde. Limit of detection and quantification was 3000 and 9900 ng/mL, respectively.

Chromatographia 70 (1-2), 309-313 (2009). TLC on silica gel with acetonitrile - methanol - dichloromethane 2:1:2. The hRf value of dutasteride was 64. Separation of dutasteride from its degradation products (produced by acid and alkali hydrolysis, oxidation, photo degradation, dry and wet heat treatment) was good. Quantitative determination by absorbance measurement at 244 nm. Linearity was in the range of 100 - 600 ng/band and the correlation coefficient was 0.9943 (via peak area) The limit of detection and quantitation was 7 and 23 ng/band.