Development of a model process for the transfer of thin layer chromatography (TLC) methods for qualitative screening of fake or counterfeit drugs, published in the Global Pharma Health Fund (GPHF) Minilab and U.S. Food and Drug Administration (FDA) Compendium of Unofficial Methods for Screening of Pharmaceuticals by TLC, to quantitative high-performance TLC (HPTLC)-densitometry methods was described in a series of papers. In this paper, HPTLC-densitometry methods developed and validated using this model process are reported for desloratadine, etodolac, famotidine, omeprazole, oxaprozin, and phenazopyridine HCl, for which qualitative screening methods have not appeared in the Minilab manual or FDA Compendium. These methods only use relatively inexpensive and nontoxic “green solvents” for sample and standard solution and mobile phase preparation, Merck Premium Purity silica gel 60 F254 plates, automated standard and sample solution application by a CAMAG Linomat 4, and automated densitometry by a CAMAG Scanner 3 for the assessment of peak purity and identity and quantification. Qualitative TLC screening methods based on the quantitative HPTLC-densitometry methods for these drugs were subsequently developed and posted with open access, as supplements to the FDA Compendium.
View Full Article