The fluorescence spectra of pharmaceutical compounds under two-photon excitation

Spectra of two-photon-excited fluorescence in pharmaceutical crystalline compounds were obtained and studied as functions of the pump power and delay time. Stimulated fluorescence was observed in polycrystalline Novocaine under high-power pumping. The spectra of two-photon-excited fluorescence in pharmaceutical compounds are localized within the wavelength range of 270–480 nm. The most intense fluorescence was observed in the Novocaine polycrystals. The therapeutic effect of diphenylhydramine and sulfanilamide is attributed to the fact that the energy of optical quanta of the fluorescence emission in these substances is higher than the energy of excited π-electrons in tryptophan and nucleotides. The data obtained for the spectra of the pharmaceutical substances studied can be used to solve analytical problems related to identification of the composition and properties of composite pharmaceutical substances.