J. Planar Chromatogr. 24, 99-104 (2011). TLC of candesartan and losartan on silica gel with 1,4-dioxane - hexane - 99 % formic acid 50:50:1. Quantitative determination by densitometry at 258 nm for candesartan and at 243 nm for losartan, videoscanning at 254 nm for both drugs. The hRf value for candesartan was 47 and for losartan 35. Linearity was between 0.2 and 1.4 µg/band for both drugs with correlation coefficients of 0.9997 and 0.9981 for candesartan, and 0.9986 and 0.9982 for losartan, for densitometry and videoscanning, respectively. Robustness (%RSD, peak area) was less than 1.9 and 0.8 % for candesartan, and 2.2 and 0.9 % for losartan in densitometry and videoscanning, respectively. The repeatability and intermediate precision (%RSD, two lowest amounts) were less than 3.6 and 4.7 % for candesartan and less than 4.7 and 5.3 % for losartan. Mean recoveries for candesartan were 103.8-104.9 % for densitometry and 99.2-100.7 % for videoscanning; for losartan the respective values were 100.8-105.4 % and 98.6-99.2 %.

J. Chil. Chem. Soc. 56, 702-705 (2011). HPTLC of lamivudine (1) and tenofovir disoproxil fumarate (2) in bulk drug and pharmaceutical dosage form on silica gel with chloroform - methanol - toluene 4:1:1. Quantitative determination by absorbance measurement at 265 nm. The hRf values of (1) and (2) were 27 and 51, respectively. Linearity was between 60-210 ng/zone for both. LOD and LOQ were found to be 20 and 40 ng/zone for (1) and 30 and 60 ng for (2). The intermediate/interday/intra-day precision was 0.6 % (n=6). Recovery (by standard addition) for (1) and (2) was between 98-102 %. The HPTLC method is suitable for routine analysis of lamivudine and tenofovir in pharmaceutical dosage form.

J. Planar Chromatogr. 24, 344-347 (2011). HPTLC of ivermectin (IVM) and albendazole (ALB) on silica gel with toluene - ethyl acetate - glacial acetic acid 12:8:1 in a twin-trough chamber saturated for 30 min. Quantitative determination by densitometry in absorbance mode at 247 nm. Linearity was between 0.12 and 0.54 µg/band for IVM and 8 and 36 µg/band for ALB. The recovery was between 98-101 % for IVM and ALB. The hRf value was 39 for IVM and 62 for ALB. LOD and LOQ were 0.02 and 0.09 µg/band for IVM and 0.08 and 0.1 µg/band for ALB. The intra-day and inter-day precision (n = 6) was 0.6 % and 1.1 % for IVM and 0.6 % and 1.2 % for ALB, respectively. Recovery (by standard addition) ranged from 98-101 % for both compounds.

J. Chil. Chem. Soc. 57, 1033-1035 (2012). HPTLC of propanolol hydrochloride (1) and flunarizine dihydrochloride (2) in combined dosage form on silica gel with methanol - toluene - ammonia 14:6:1. Quantitative determination by absorbance measurement at 267 nm. The hRf of compounds (1) and (2) were 63 and 48, respectively. Linearity was in the range of 800-4800 ng/zone for (1) and 200-1200 ng/zone for (2). Limits of detection and quantification were 25 and 75 ng/zone for (1) and 16 and 48 ng/zone for (2), respectively. Intermediate/intra-day/inter-day precision was below 2.0 % (n=6). Recovery for both (1) and (2) was between 99.3 and 100.9 %.

J. Planar Chromatogr. 26, 62-66 (2013). HPTLC of propranolol hydrochloride (1) and flunarizine dihydrochloride (2) on silica gel with methanol - chloroform - toluene 6:14:14+1 drop glacial acetic acid. Quantitative determination by absorbance measurement at 260 nm. The hRf values of (1) and (2) were 35 and 64, respectively. Linearity was in the range of 3000-15000 ng/zone and 750-3700 ng/zone for (1) and (2), respectively. Intermediate precision was below 2 %.

J. Planar Chromatogr. 26, 435-439 (2013). HPTLC of ciclesonide in bulk and dosage form on silica gel with acetonitrile - 1,4-dioxane - n-hexane 1:1:8 +1 drop ethyl acetate. Quantitative determination by absorbance measurement at 242 nm. The hRf of ciclesonide was 38. Linearity was between 1 and 6 mg/zone. LOD and LOQ were 100 and 303 ng/zone. Recovery (by standard addition) was found to be 98.9-100.3 %. Intra- and inter-day precision values were below 0.7 and 1.4 %, respectively.

J. Planar Chromatogr. 27, 428-430 (2014). HPTLC of (1) tretinoin and (2) isotretinoin on silica gel with toluene – ethyl acetate – methanol 16:2:1. Quantitative determination by absorbance measurement at 334 nm. The hRF values of (1) and (2) were 27 and 38, respectively. Linearity was in the range of 30-70 ng/zone for (1) and (2). The intermediate precision was below 1 % (n=6) for (1) to (2). The LOD and LOQ were 10 and 20 ng/zone for (1) and 20 and 30 ng/zone for (2). Recovery for (1) and (2) were in the range of 95-102 %.

J. Planar Chromatogr. 29, 140-144 (2016). HPTLC of atovaquone (1) and proguanil (2) in tablets on silica gel with toluene – methanol – glacial acetic acid 40:10:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 80 and 22, respectively. Linearity was in the range of 200-2000 ng/zone for (1) and 100-1000 ng/zone for (2). Intermediate precisions were below 1 %. The LOD and LOQ were 41 and 123 ng/zone for (1) and 31 and 94 ng/zone for (2), respectively. Recovery was in the range of 99.5-100.7 % for (1) and 100.1-100.8 % for (2).