J. Planar Chromatogr. 34, 279-283 (2021). HPTLC of linagliptin on silica gel with toluene - methanol 7:3. Quantitative determination by absorbance measurement at 294 nm. The hRF value for linagliptin was 91. Linearity was between 100 and 500 ng/zone. Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 0.26 and 0.78 ng/zone, respectively. Recovery was between 99.1 % and 101.2 %.

J. Planar Chromatogr. 34, 243-252 (2021). HPTLC of dapagliflozin (1) and metformin (2) on silica gel with methanol - ethyl acetate - ammonium acetate 60:40:1. Quantitative determination by absorbance measurement at 220 nm. The hRF values for (1) and (2) were 79 and 31, respectively. Linearity was between 20 and 100 ng/zone for (1) and 500 and 2500 ng/zone for (2), respectively. Intermediate precisions were below 2 % (n=5). The LOD and LOQ were 3 and 10 ng/zone for (1) and 11 and 34 ng/zone for (2), respectively. Recovery was between 100.0 % and 101.6 % for (1) and 99.7 % and 101.1 % for (2).

J. Sep. Sci. 44, 530-538 (2021). HPTLC of tamsulosin (1) and tadalafil (2) in presence of their degradation products (2) and (3) on silica gel with ethyl acetate - toluene - methanol - ammonia 20:10:20:3. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (4) were 55, 68, 14 and 24, respectively. Linearity was between 0.5 and 25 µg/zone for (1) and (2). Intermediate precision was below 2 % (n=3). Average recovery was 99.7 % for (1) and 100.3 % for (2).

J. Planar Chromatogr. 33, 631-646 (2020). HPTLC of azilsartan medoxomil (1) and chlorthalidone (2) on silica gel with toluene - methanol - ethyl acetate - formic acid 35:10:5:1. Quantitative determination by absorbance measurement at 241 nm. The hRF values for (1) and (2) were 55 and 36. Linearity was between 800 and 4000 ng/zone for (1) and 250 and 1250 ng/zone for (2), respectively. Intermediate precision was below 2 % (n=3). The LOD and LOQ were 15 and 44 ng/zone for (1) and 10 and 32 ng/zone for (2). Recovery was between 100.8 and 101.7 % for (1) and 99.4 and 101.0 % for (2).

J. of Chromatogr. Sci. 59 (6), 536-547 (2021). HPTLC of pregabalin (PGB) and amitriptyline (AMT) as an active binary mixture in pure forms or in human biological fluids (plasma/urine)  on silica gel with ethanol - ethyl acetate - acetone - ammonia solution 160:40:20:1. Detection by spraying with 3 % ethanolic ninhydrin solution. Quantitative determination by densitometry at 220 nm for AMT and 550 nm for PGB peaks after derivatization. The linearity range was 0.2 - 2.5 μg/band for PGB and 0.1-2.0 μg/band for AMT.

J. of Chromatogr. Sci. 59(5), 425–431 (2021). HPTLC of bromhexine hydrochloride (BHX), impurity B (IMB) and impurity C (IMC) on silica gel with hexane - acetone - ammonia solution 450:25:4. Quantitative determination by densitometry at 240 nm. The linearity was in the range of 0.40-10.00, 0.20-2.00 and 0.20-2.00 μg/band for BHX, IMB and IMC, respectively. Comparison with an HPLC method showed no significant differences regarding accuracy and precision.

J. of Chromatogr. Sci. 59 (2), 140-147 (2021). TLC of paracetamol (PC), propyphenazone (PZ) and caffeine (CF) in the presence of the two PC impurities 4-aminophenol and 4-nitrophenol, on silica gel with chloroform - toluene - ethyl acetate - methanol - acetic acid 60:60:10:20:1. Quantitative determination by densitometry at 220 nm.

J. of Chromatogr. Sci. 58 (5), 427 - 432 (2020). HPTLC of ulipristal acetate (UPA) in presence of its degradation products on silica gel with ethyl acetate - toluene - glacial acetic acid 40:70:3. UPA was subjected to acid and alkali hydrolysis, oxidation, photo and thermal degradation. The hRF of UPA was 38. Quantitative determination by densitometry. The linearity range was between 400-3600 ng/band. LOD was 72 ng/band and LOQ 220 ng/band. The recovery was 100.1-100.7 %. The method is accurate, precise, robust, and specific to measure UPA in presence of degradants.