Development of derivative spectrophotometric method for simultaneous determination of pyrazinamide and rifampicin in cubosome formulation

Abstract

The ultraviolet spectrophotometry analysis for quantitative assay of drugs is a method accurate, sensitive, selective and reproductive with the advantage of being a simple and less expensive method. In this study, a derivative ultraviolet spectrophotometric method was developed for simultaneous determination of pyrazinamide (PYZ) and rifampicin (RIF). The spectrophotometric method was evaluated according to validation guidelines for specificity, linearity, limits of detection and quantification, precision, accuracy and robustness. The first-derivative spectra were obtained and by the zerocrossing point, the wavelength 247 nm and 365 nm were selected for PYZ and RIF quantification, respectively. No interference from cubosome excipients was detected in the proposed method. The results demonstrated linearity in a range of 4.0 – 12.0 µg/mL with an adequate correlation coefficient for both drugs. The intra and inter-day precision results (RSD < 5%) indicated the reproducibility of the method. The accuracy data showed satisfactory results (RSD < 5%) from recovery test. In addition, the robustness results showed that the PYZ and RIF content were unaffected by the solvent alteration of methanol to methanol:water (99:1, v/v). The derivative ultraviolet spectrophotometric method proved to be an excellent strategy for simultaneous determination of PYZ and RIF.

State of the Art on Developments of (Bio)Sensors and Analytical Methods for Rifamycin Antibiotics Determination

“…UV-Vis spectrometric methods present narrower linear ranges and are less sensitive; therefore, according to the data summarized in Table 2 , most RIF determinations based on absorbance measurements may be applied as reported for the assessment of RIF blood concentration. Only a few of them required sample dilution [ 127 , 129 , 133 ], while the methods using a reagent p-chloranil or Fe(III) [ 139 ] are not applicable for such types of analysis. Regarding luminescence-based methods ( Table 3 and Table 4 ), only one cannot be applied to RIF determination in blood samples [ 151 ].…”

“…On the other hand, some reports described the “zero-crossing” method applied to the first order derivative spectra. In this case, RIF was determined at the zero-crossing point of the other(s) coexisting analyte(s), where it presented a linear ΔA/Δλ = f (C) dependence [ 126 , 127 ]. The Q-AR method was also reported to be applied for the quantification of RIF in the presence of another compound (e.g., piperine [ 128 ] and CC-I [ 129 ]).…”