Comparison of UV spectrophotometric and LC methods for the determination of nortriptyline hydrochloride in polysorbate 80 based oil/water (o/w) microemulsions

A new rapid, reliable and specific UV spectrophotometric method was develop ed for the determination of nortriptyline hydrochloride formulated into o/w microemulsions. The UV spectra of nortriptyline standard solution in metha nol and placebo (microemulsion without nortriptyline) were recorded over th e wavelength range 200-600 nm and the spectra for placebo and nortriptyline loaded microemulsion were recorded over the range 260-400 nm in order to d etermine the overlapping that might appears, and hence to set the wavelengt h that could be used for the quantitative analysis. This method was validat ed and compared with a liquid chromatography (LC) procedure used for the qu antitative analysis of the drug. Both methods showed excellent precision an d accuracy with RSD values of 2.37 and 1.41%, respectively, for the LC meth od, and values of 1.24 and 2.88%, respectively, for the UV spectrophotometr ic method. The established linearity range was 10-50 mu g ml(-1) (r(2) = 0. 9985) and 20-60 mu g ml(-1) (r(2) = 0.9979) for the HPLC and UV spectrophot ometric methods respectively. The recoveries of nortriptyline from spiked p lacebos were > 95% for both methods over the linear range. The methods have been successfully used for determining the nortriptyline content of microe mulsions and for evaluating the chemical stability of the drug in nortripty line-loaded microemulsions. (C) 2000 Elsevier Science B.V. All rights reser ved.