Fig. 5From: Development and validation of derivative UV spectroscopic method for simultaneous estimation of nicotinamide and tretinoin in their binary mixtures and pharmaceutical preparationsThe first-order derivative spectrograms show nicotinamide spectrum 30 µg/mL (A), nicotinamide series (A10–A80), tretinoin standard series (B1–B3), solution formula (S), and cream formula (C)Back to article page