A rapid, simple and direct assay procedure based on first-derivative spectrophotometry, using a zero-crossing and peak-to-base measurement at 234 and 324 nm, respectively, has been developed for the specific determination of dextromethorphan HBr and bromhexine HCl in tablets. Calibration graphs were linear with the correlation coefficients of 0.9999 for both analytes. The limit of detections we...

The determination of stoichiometries and stability constants of complexes by means of UV-visible spectrophotometry applying traditional methods does not evaluate the quality of the values obtained, since the classic application of these methods does not provide coverage intervals. However, the use of chemometric techniques in different steps of the application of these methods makes it possible...

Damage resulting from the incidence of ultraviolet (UV) radiation on skin is common nowadays, with UVB (290-320 nm) and UVA (320-400 responsible for photoaging, sunburn carcinogenesis. For this reason, sunscreens represent products growing interest to prevent such damage. However, there are few organic filters marketed worldwide photostability effectiveness at wavelengths greater than 340 nm (l...