J. Planar Chromatogr. 23, 50-55 (2010). HPTLC of andrographolide on silica gel with chloroform - methanol - ethyl acetate 12:3:2 in a twin-trough chamber previously saturated for 15 min. Quantitative determination by absorbance measurement at 223 nm. The relative standard deviation of intra-day and inter-day analysis was in the range of 0.56-1.33 %. Lineartiy was given between 200-700 ng/band; the correlation coefficient was 0.9998 and the RSD 0.97 %. The limits of detection and quantification were 60 and 150 ng/band. Average recovery was 98.8 +- 0.41 %.

Abstract No. C-372, 61st IPC (2009). HPTLC of withanolide A in extracts and spansules dosage form on silica gel with toluene - ethyl acetate - formic acid 8:6:1. Densitometric evaluation at 254 nm. Withanolide A was well separated with an hRf value of 14. The linearity range was 40-200 ng/band.

J. Ethnopharmacol. 130, 267-271 (2010). HPTLC of evodione and leptonol from the leaves and influorescences of Melicope lunu-ankenda on silica gel with chloroform - methanol 1:1. Detection by spraying with anisaldehyde - sulfuric acid reagent, followed by heating at 105 °C for 5 min. Quantitative determination by absorbance measurement at 580 nm.

J. Liq. Chromatogr. Relat. Technol. 33, 825-836 (2010). NP-TLC of ibuprofen standard and in tablet extracts on silica gel (prewashed with methanol) with n-hexane - ethyl acetate - acetic acid 150:50:7 and RP-TLC on RP18 with methanol - water 9:1 in a saturated twin-trough chamber. Quantitaitve determination by absorbance measurement at 200 and 224 nm for NP-TLC and RP-TLC analysis, respectively. The hRf values were 61 and 67. Linearity was between 2.50-12.50 and 2.50-12.50 µg/spot, the correlation coefficient (r) was 0.998 and 0.994. LOD was 0.60 and 1.00 µg/spot, and LOQ 12.50 and 12.50 µg/spot. Recovery was 98.2 % and 96.1 %, with a standard deviation of 1.21 and 1.45, and RSD 1.28 and 1.81 for NP-TLC and RP-TLC, respectively.

J. Liq. Chromatogr. Relat. Technol. 33, 748-760 (2010). HPTLC of mercury(II), copper(II), nickel(II), cadmium(II), mercury(II), lead(II), cobalt(II), manganese(II), palladium(II), platinum(II), and zinc(II) as porphyrin complexes using newly synthesized tetra-(bromo-4-hydroxyphenyl) porphyrin (TBHPP), tetra-(4-phenoxyphenyl) porphyrin (TPPP) and tetra-p-chloromethylphenyl porphyrin (CMPP) on silica gel with acetone - chloroform 1:4 for TBHPP and TPPP and dichloromethane - chloroform - hexane 1:1:3 for CMPP. The hRF values were determined for the metal-TBHPP, -TPPP, and -CMPP chelates. Detection was performed by absorbance measurement at 420 nm. The linear range was 3.6-60, 3.6-30, 1.2-30, 0.6-30, 0.6-30, 2.4-60 ng/µL, LOD was 0.90, 0.92, 0.36, 0.19, 0.16, and 0.41 ng/µL, and LOQ was 3.01, 3.06, 1.11, 0.54, 0.54, 0.54, and 1.36 ng/µL. Intermediate precision (RSD%, n = 5) (6 ng/µL) was 3.55, 4.25, 3.20, 3.85, 2.25, 0.45 % and the regression coefficient was 0.9908, 0.9904, 0.9944, 0.9961, 0.9972, and 0.9942. The hRf values were 68, 16, 83, 42, 67, and 76 for Hg-TBHPP, Zn-TBHPP, Cu-TBHPP, Co-TBHPP, Hg-TBHPP, and Cu-CMPP, respectively.

Ind. J. Pharma. Sci. 72(1), 86-91 (2010). Three species of Plumbago (Plumbaginaceae), i.e. P. zeylanica, P. carpensis, and P. rosea were studied for different physico-chemical parameters in addition to the estimation of microbial contamination, aflatoxins and pesticide residues and heavy metal content. All three species are used as herbs. The fingerprint profile of each species was compared using plumbagin as marker. Chloroform extracts of each plant were subjected to chromatography on silica gel with toluene - ethyl acetate 4:1 in a saturated twin trough chamber. Detection under UV 254 nm and 366 nm. The hRf value of plumbagin was 70. The identity of plumbagin in the samples was shown by overlay of the UV spectra. Linearity was between 200 and 1000 ng/zone. The amount of plumbagin in the three species was between 0.01 and 0.17 %.

Scholars Research Library 2(2), 328-332 (2010). A validated densitometric method has been development for simultaneous estimation of drotaverine and aceclofenac in combined dosage form. TLC on silica gel with methanol - ethyl acetate - glacial acetic acid 100:90:1. The hRf value of drotaverine was 18 and of aceclofenac 51. Densitometric evaluation at 300 nm. The method was linear in the range of 80-360 ng/band for drotaverine and 100-700 ng/band for aceclofenac. The average recovery was 99.8-100.2 %.

Research J. Pharm. and Tech. 3(4), 1275-1278 (2010). A stability indicating HPTLC method has been developed for ofloxacin. The results were confirmed by bioautography. HPTLC on silica gel with n-butanol - ethanol - 25 % ammonia 5:5:4. The hRf value was 53. Densitometric evaluation at 299 nm. The method was linear in the range of 500-2500 ng/band. The sample was subjected to forced degradation (acid, base, oxidation, thermal, photolytic) and both degraded and un-degraded sample were analyzed by HPTLC and bioautography. The result obtained by bioautography confirmed that the antimicrobial activity of ofloxacin was directly related to its degree of degradation under different stress conditions. Further no inhibition zone was observed at another hRf than that of ofloxacin, which indicates that degradation products do not exhibit antibacterial activity. Bioautography studies were carried out in petri plates (10 cm diameter) using as media Mueller Hinton agar and as organism Escherichia coli NCIM 2066.