Comparison of classic and derivative UV spectrophotometric methods for determination of dextromethorphani hydrobromidum

A method for the fast determination of dextromethorphani hydrobromidum in pharmaceutical preparations by classic spectrophotometry - zero and first-, second- and third-order derivative spectrophotometry, using "peak - peak" (P - P) and "peak - zero" (P - O) measurements has been performed. The calibration curves are linear within the concentration range of 1.0 - 25.0 μg ml^-1 for dextromethorphani hydrobromidum. The procedure is simple, rapid and the results are reliable.