Resumo

QUINO, Israel; CHOQUE, Rigoberto  e  CACERES C., Luis Fernando. VALIDACIÓN DE UNA NUEVA DETERMINACIÓN ESPECTROFOTOMÉTRICA PARA DIPIRONA EN FÁRMACOS. Rev. Bol. Quim [online]. 2005, vol.22, n.1, pp.64-70. ISSN 0250-5460.

We present a method for the spectrophotometric UV absorption determination of the dipirone ([(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pirazol-4-il)-N-ethylammoniun] metansulfonate) as well as sodium (DPNa) and magnesium (DPMg) salts. The principle of determination is based on the molecular absorption of the dipirone in acid medium at 257 nm of wavelength. Both dipirone types, present a maximum of absorption between 257-258 nm, with the only difference for magnesic dipirone that presents another peak at 293 nm. The method was validated and it fulfills control requirements and insurance of quality recommended by the FDA (Food and Drugs Administration, USA). The method is selective and sensitive, with detection and quantification limits from 0,011 to 0,037 mgL^-1 for DPNa, and 0,036 to 0,120 mgL^-1 for the DPMg respectively, which makes possible quantification of for instance impurities or their traces of other active principles. Linear responses are obtained up to 100 mgL^-1, with a r² = 0.99919. The selectivity and robustness of the analytic method was verified, determining the dipirone content in three pharmaceutical forms (tablets, drops, and injectable), coming out from the local pharmaceutical industry as well as the foreign one. In all the cases, percentages of recovery were about 92 -111%.