The heterogeneous composition of pharmaceutical-grade nystatin
Samples of nystatin from different manufacturers have been analysed biologically and chemically. Examination by high-performance and thin-layer chromatography has shown that pharmaceutical-grade nystatin is a complex mixture. The composition of nystatin varied with the source of manufacture. The existing pharmacopoeial specifications were unable to detect these wide differences in composition. For the atypical samples there was a significant difference between the potency estimates obtained with S. cerevisiae and C. tropicalis; no such differences were apparent with the other nystatin samples examined.