Development and validation of a method for allantoin determination in liposomes and pharmaceutical formulations

The aim of this work was to develop and validate an ultraviolet derivative spectrophotometric (UVDS) method for the quantitative determination of allantoin (ALL) in liposomes, gels and creams. Liposomes were prepared by methods of thin film hydration and mechanical agitation. Solutions of ALL in 0.1 mol/L NaOH with ethanol:water (70:30, v/v) were prepared in order to destroy liposome vesicles. Spectral interference from components of liposomes, cream, gel and ALL degradation products was eliminated using the second-order derivative of the zero-order spectrum. Characterization of ALL in 0.1 mol/L NaOH was carried out by direct infusion mass spectrometry. Absorbances of ALL solutions were measured at 266.6 nm of the second-derivative spectrum and linearity was observed in the ALL concentration range of 50–300 μg mL−1 (correlation coefficient (r) = 0.9961). The mean recovery percentage was 100.68 ± 1.61, repeatability expressed as relative standard deviation (RSD) was 1.07 and 2.12%, and intermediate precision (RSD) was 2.16%. The proposed UVDS method was found to be linear, precise, accurate, robust and selective, providing rapid and specific determination of ALL in raw materials and in topical formulations.

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► An ultraviolet derivative spectrophotometric method for rapid and specific determination of allantoin raw material and in topical formulations was developed and validated.
► Assessment of the developed method was accomplished by mass spectrometry.
► The abundant ion obtained in the mass spectra of allantoin in 0.1 N NaOH solution corresponds to that of deprotonated parabanic acid.
► The UVDS method was linear, precise, accurate, robust and selective.