title: First-derivative spectrophotometric and LC determination of nifedipine in Brij 96 based oil/water/oil multiple microemulsions on stability studies.
abstract: A first-derivative spectrophotometric (1D(387)) method was developed for the determination of nifedipine in oil/water/oil (O/W/O) multiple microemulsions during stability studies. The UV first-derivative spectra were recorded over the wavelength range 200-600 nm (Delta lambda=16). The derivative procedure was based on the linear relationship between nifedipine concentration and the first-derivative amplitude at 387 nm. This method was validated and compared with a liquid chromatography (LC) procedure used for the quantitative analysis of the drug. Both methods showed excellent precision and accuracy with values of 2.09 and 1.82%, respectively, for the LC method and of 1.53 and 1.64%, respectively, for the 1D(387) method. The established linearity range was 5-30 microg ml(-1) with r(2) values of 0.9980 and 0.9988 for LC and first-derivative procedures, respectively. Nifedipine recoveries from spiked placebos were >95% for both methods over the linear range analysed. These methods have been successfully used for determining of nifedipine content of multiple microemulsions during stability studies, since there was no interference with its decomposition products.
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain. marco@eucmax.sim.ucm.es
authors.forename: D
authors.initials: D
authors.lastname: Castro
authors.forename: M A
authors.initials: MA
authors.lastname: Moreno
authors.forename: J L
authors.initials: JL
authors.lastname: Lastres
mesh_terms: D002121:Calcium Channel Blockers; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D004655:Emulsions; D009543:Nifedipine; D013053:Spectrophotometry; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D002121:Calcium Channel Blockers; D004655:Emulsions; D009543:Nifedipine