Background: The development and introduction of combined therapy represent
a challenge for analysis due to severe overlapping of their UV spectra in case
of spectroscopy or the requirement of a long tedious and high cost separation technique
in case of chromatography. Quality control laboratories have to develop and
validate suitable analytical procedures in order to assay such multi component preparations.
Methods: New spectrophotometric methods for the simultaneous determination of
simvastatin (SIM) and nicotinic acid (NIA) in binary combinations were developed.
These methods are based on chemometric treatment of data, the applied chemometric
techniques are multivariate methods including classical least squares (CLS), principal
component regression (PCR) and partial least squares (PLS). In these techniques, the
concentration data matrix were prepared by using the synthetic mixtures containing
SIM and NIA dissolved in ethanol. The absorbance data matrix corresponding to the
concentration data matrix was obtained by measuring the absorbance at 12 wavelengths
in the range 216 – 240 nm at 2 nm intervals in the zero-order. The spectrophotometric
procedures do not require any separation step. The accuracy, precision and the linearity
ranges of the methods have been determined and validated by analyzing synthetic mixtures
containing the studied drugs.
Conclusion: Chemometric spectrophotometric methods have been developed in the
present study for the simultaneous determination of simvastatin and nicotinic acid in
their synthetic binary mixtures and in their mixtures with possible excipients present in
tablet dosage form. The validation was performed successfully. The developed methods
have been shown to be accurate, linear, precise, and so simple. The developed methods
can be used routinely for the determination dosage form.