4. Conclusion
The HPLC stability-indicating method of ascorbic acid quantitation
in semisolid pharmaceutical/cosmetic preparations containing
glutathione and sodium metabisulfite, as antioxidants,
described in the present study was validated by linearity, sufficient accuracy/recovery and precision, as well as low values
of limits of detection and quantification, presenting the sensitivity
of this analytical tool. The simplicity of the low cost
non-consuming time technique and the high specificity to ascorbic
acid, even in the presence of the variety of excipients and
its possible degradation product, the oxalic acid, provided this
stability-indicating method to be particularly attractive for the
determination of ascorbic acid on these o/w emulsion and aqueous
gel or in other similar pharmaceutical/cosmetic formulations