Determinación de clorhidrato de nafazolina por cromatografía líquida de alta resolución en una solución oftálmica / Naphazoline hydrochloride assay by high performance liquid chromatography in an ophthalmic solution

Introducción: la Farmacopea de los Estados Unidos orienta cómo valorar clorhidrato de nafazolina en una solución oftálmica, pero indica el uso de una columna con grupos nitrilos unidos a sílice porosa, de uso poco frecuente. Objetivo: desarrollar y validar un método alternativo por cromatografía líquida de alta resolución (CLAR) para la cuantificación de clorhidrato de nafazolina en una solución oftálmica. Métodos: el método desarrollado fue de separación isocrática con columna Zorbax SB-C18 (4,6 x 150 mm, 5 µm) y detección ultravioleta a 225 nm. Como fase móvil se empleó solución amortiguadora y acetonitrilo (proporción 85:15, v/v) y la solución amortiguadora fue de KH2PO4 (22 mM) y trietilamina (30 mM), ajustada a pH 3 con ácido fosfórico concentrado. La validación del método se realizó siguiendo las indicaciones de la Guía Q2(R1) de la Conferencia Internacional sobre la Armonización. Se evaluaron los parámetros siguientes: especificidad, precisión, exactitud, linealidad y rango. También se determinó la incertidumbre del método. Resultados: en la especificidad, el placebo no tuvo señal en la zona de clorhidrato de nafazolina; los coeficientes de variación obtenidos para la precisión intermedia resultaron inferiores a 1,5 por ciento; en la exactitud el recobrado fue de 101,52 por ciento y en la linealidad se demostró la ausencia de curvatura en el intervalo 50 a 150 por ciento. La incertidumbre expandida calculada fue un 3 por ciento de la cantidad declarada. Conclusiones: todos los parámetros de validación evaluados se encuentran dentro los límites de aceptación establecidos, por lo que el método es adecuado para los fines propuestos(AU)

Introduction: the United States Pharmacopeia specifies how to titer naphazoline hydrochloride in an ophthalmic solution, but suggests the use of a column with nitrile groups attached to porous silica which is barely used. Objective: to develop and to validate an alternative method by high resolution liquid chromatography for the quantification of naphazoline hydrochloride in an ophthalmic solution. Methods: the developed method was isocratic separation with a Zorbax SB-C18 column (4.6 x 150 mm, 5 µm) and ultraviolet detection set at 225 nm. The mobile phase was buffer and acetonitrile (85:15 ratio, v/v) and the buffer was KH2PO4 (22 mM) and triethylamine (30 mM), adjusted to pH 3 with concentrated phosphoric acid. The validation method was performed pursuant to the Guide Q2(R1) of the International Conference on Harmonization and the following parameters were evaluated: specificity, precision, accuracy, linearity and range. The method uncertainty was also estimated. Results: regarding the specificity, the placebo did not show any signal in the naphazoline hydrochloride zone; the relative standard deviation indexes for intermediate precision were less than 1.5 percent; as to accuracy, the recovery was 101.52 percent and the linearity showed absence of curvature in the 50 to 150 percent range. The estimated expanded uncertainty reached 3 percent of the stated amount. Conclusions: all the validation parameters under evaluation were within the set allowable limits, thus this method is suitable for the intended purposes(AU)

In situ modified screen printed and carbon paste ion selective electrodes for potentiometric determination of naphazoline hydrochloride in its formulation / 药物分析学报

The construction and performance characteristics of new sensitive and selective in situ modified screen printed (ISPE) and carbon paste (ICPE) electrodes for determination of naphazoline hydrochloride (NPZ-HCl) have been developed. The electrodes under investigation show potentiometric response for NPZ-HCl in the concentration range from 7.0 ? 10-7 to 1.0 ? 10-2 M at 25 1C and the electrode response is independent of pH in the range of 3.1-7.9. These sensors have slope values of 59.770.6 and 59.270.2 mV decade?1 with detection limit values of 5.6 ? 10-7 and 5.9 ? 10-7 M NPZ-HCl using ISPE and ICPE, respectively. These electrodes show fast response time of 4-7 s and 5-8 s and exhibits lifetimes of 28 and 30 days for ISPE and ICPE, respectively. Selectivity for NPZ-HCl with respect to a number of interfering materials was also investigated. It was found that there is no interference from the investigated inorganic cations, anions, sugars and other pharmaceutical excipients. The proposed sensors were applied for the determination of NPZ-HCl in pharmaceutical formulation using the direct potentiometric method. It showed a mean average recovery of 100.2%and 102.6%for ISPE and ICPE, respectively. The obtained results using the proposed sensors were in good agreement with those obtained using the official method. The proposed sensors show significantly high selectivity, response time, accuracy, precision, limit of detection (LOD) and limit of quantification (LOQ) compared with other proposed methods.