Thin-layer chromatographic determination of procainamide and N-acetylprocainamide in human serum and urine at single-dose levels.

Thin-layer chromatographic methods were applied for bioavailability studies of procainamide in serum and urine. Detection of the parent compound and the major metabolite was performed in the ultraviolet range at 275 nm. Using 100-microliter samples, detection limits were 60 ng of procainamide-HCl per ml serum and 7 micrograms/ml urine, and 60 ng of N-acetylprocainamide-HCl per ml serum and 5 micrograms/ml urine. Advantages over previous methods are discussed. From serum and urine data of five volunteers, the bioavailability of procainamide from a 250-mg dragee preparation compared with an intravenous dose was verified. Pharmacokinetic data were computed using one-compartment open models. Results corresponded well with values previously published.