CBS 95, 9 (2005). HPTLC of glyphosate and AMPA derivatized in situ on the application position of the plate with FMOC, on silica gel with n-butanol - water - acetic acid 5:1:1 over 70 mm in an unsaturated twin trough chamber. After drying dipping in paraffin - toluene 1:1 for fluorescence enhancement. Quantitative determination by fluorescence measurement with mercury lamp at 265/M 360 nm. Linear calibration using peak height, LOD 0.5 ng absolute per substance zone for glyphosate-FMOC and 0.2 ng for AMPA-FMOC.

J. Pharm. Biomed. Anal. 38, 180-185 (2005). A stability indicating HPTLC method is reported for estimation of cyclophosphamide in pharmaceutical preparations. HPTLC on silica gel with dichloromethane - methanol - acetic acid 97:3:2. Detection with alcoholic phosphomolybdic acid solution followed by heating at 190 °C for 10 min. Quantitative determination by absorbance measurement at 700 nm. Linearity was obtained between 0.40-1.20 mg/mL with recovery rates of 99.5 %. The method was validated for selectivity, specificity, accuracy, precision, and found to be stable for 28-70 days.

Abstract GP-18, IPC (2005). HPTLC of nimesulide and chlorzoxazone in tablets on silica gel (prewashed with methanol) with toluene - acetone - ammonia 50:50:4. Paracetamol was used as internal standard. Quantitative determination by absorbance measurement at 265 nm. Nimesulide, chlorzoxazone and paracetamol showed hRf values of 80, 73 and 42, respectively. Linearity was obtained between 0.2-1.0 mg/mL with recovery rates of 99.6-100.3 % for both compounds.The method was validated for accuracy, precision, linearity, LOD, and LOQ.

Abstract D-12, IPC (2005). HPTLC of methanol and ethyl acetate extracts of trigonella foenum graecum on silica gel with n-propanol - ammonia 11:9. Detection by spraying with ninhydrin reagent. Quantitative determination by absorbance measurement and in visible range. The hRf value of isoleucin was 60. Methanolic extracts contained 0.17 % isoleucin and ethyl acetate extracts 0.008 %. Accuracy, precision, linearity of the method were established.

CBS 96, 11-13 (2006). HPTLC of isopropylthioxanthone (ITX) in food, on silica gel in horizontal developing chamber with toluene - n-hexane 4:1 over 50 mm. Quantitative determination by fluorescence measurement at UV 254/>400 nm. Polynomial calibration via peak height, working range was 20 - 200 µg/kg. LOD is 64 pg (n=3) and in spiked fatty matrix 1 µg/kg. Positive findings were confirmed by ESI-MS in selective ion monitoring mode at m/z 255 and 277 using a plunger-based extraction device. Further confirmation by DART directly coupled to TOF-MS.

Talanta 61 (5), 581-589 (2003). TLC of clopidogrel bisulphate on silica gel with carbon tetrachloride - chloroform - acetone 12:8:3. Rf value of clopidogrel bisulphate was 0.30. Clopidogrel bisulphate was subjected to acid and alkali hydrolysis, oxidation, photodegradation and dry heat treatment. The drug was susceptible to acid - base hydrolysis, oxidation and dry heat degradation. Also the degraded products were well separated from the pure drug with significantly different Rf values. Quantitative determination by absorbance measurement at 230 nm. The linear regression data for the calibration plots showed good linear relationship with r2=0.999 in the concentration range of 200-1000 ng. The mean value of correlation coefficient, slope and intercept were 0.999±0.001, 0.093±0.011 and 8.83±0.99, respectively. The method was validated for precision, accuracy, ruggedness and recovery. The limits of detection and quantitation were 40 and 120 ng per spot, respectively.

J. Planar Chromatogr. 19, 204-207 (2006). HPTLC of florfenicol on silica gel in a twin-trough chamber with ethyl acetate - n-hexane 4:1. Quantitative determination by absorbance measurement at 223 nm. Linearity range of calibration curve was 20 -80 ng with a correlation coefficient r2 of 0.9987. Limit of detection was 2.55 mg / kg and limit of quantification was 8.50 mg / kg. Recovery was 101.7 % at 50 mg /kg, 85.2 % at 500 mg / kg and 81.9 % at 1500 mg / kg. Precision was evaluated based on intra-laboratory dispersion or repeatability. RSD for 50, 500, and 1500 mg / kg was 2.30, 2.72, and 3.57 % respectively.

Indian J. Pharm. Sci. 67 (2), 182-186 (2005). HPTLC of atorvastatin calcium in its commercial single component tablet formulations (10 mg/tablet), on silica gel with benzene-methanol 7:3. The Rf value was 0.46. Quantitative determination by absorbance measurement at 281 nm. The method was validated in terms of linearity (200-600 ng/spot), precision (intraday variation: 0.25 - 1.01 %, interday variation: 0.21 - 0.88 %), accuracy and specificity. The LOD for atorvastatin calcium was 40 ng/spot, the LOQ was 200 ng/spot. The proposed method was successfully applied to determine atorvastatin calcium content of 10 individual tablet units of two market formulations after extracting atorvastatin calcium with methanol. All formulations were compliant with USP specifications (RSD less than or equal to 6 %) of the content uniformity test. The proposed HPTLC method can analyse ten or more formulation units simultaneously on a single plate and provides a faster and cost effective quality control tool for routine analysis of atorvastatin calcium formulation.