Simultaneous determination of lovastatin and niacin in tablet by first and third derivative spectrophotometry and H-point standard addition methods

Abstract

Most cardiovascular diseases need to be treated by more than a simple drug and the use of combination products diminishes noncompliance. Advicor(®) as a combination product of a vitamin and a fat lowering agent has no monograph in official pharmacopeias for its quality control purposes. In this study, first and third derivative signals for NA and LV quantitation at the two pairs of wavelengths, 261 and 273 nm; 245 and 249 nm were monitored with the addition of standard solutions of NA or LV, respectively. The limits of detection were 0.03 and 0.32 mg/L for LV and NA, respectively. The limits of quantitation were 0.09 and 0.78 mg/L for LV and NA, respectively. RSD% for both interday and intraday precision was lower than 2.6 and 2.7% for LV and NA, respectively. Selectivity of the method was assessed for both degradation products produced in stress conditions and common excipients that may present in the pharmaceutical dosage forms. The recommended procedure was successfully applied to real samples.

Keywords: Derivative spectrum; HPSAM; Lovastatin; Niacin; Spectrophotometry.

Fig. 1

Different orders of derivation of NA and LV, I) Zero order derivative spectra of a: NA (50 mg/L) and b: LV (1 mg/L); II) first derivative spectra of a: NA (50 mg/L) and b: LV (1 mg/L); III) third derivative spectra of a: NA (50 mg/L) and b: LV (1 mg/L).

Fig. 2

Plots of H-point standard addition method for determination of NA (50 mg/L) in the presence of LV (1 mg/L) when different standard NA solutions (5, 10, 15, 20, and 25 mg/L) were added.

Fig. 3

Plots of H-point standard addition method for a) fixed LV concentration (1 mg/L) and different concentrations of NA; and b) fixed NA concentration (50 mg/L) and different concentrations of LV. Standard additions are performed by NA standards.

Fig. 4

Plots of H-point standard addition method for determination of LV (1 mg/L) in the presence of NA (50 mg/L) when different standard LV solutions (0.2, 0.4, 0.6, 0.8, and 1 mg/L) are added.

Fig. 5

Plots of H-point standard addition method for a) fixed LV concentration (1 mg/L) and different concentrations of NA; and b) fixed NA concentration (50 mg/L) and different concentrations of LV. Standard additions are performed with LV standards.