Simultaneous spectrophotometric determination of diuretics by using multivariate calibration methods.

Area of Science:

• Analytical Chemistry
• Pharmaceutical Analysis

Background:

• Accurate quantification of pharmaceutical compounds in mixtures is crucial for drug quality control.
• Partial Least-Squares (PLS) regression is a chemometric technique applicable to complex mixture analysis.

Purpose of the Study:

• To optimize the wavelength range and number of factors for PLS calibration.
• To develop and validate a method for resolving binary (dihydralazine-hydrochlorothiazide) and ternary (dihydralazine-hydrochlorothiazide-reserpine) mixtures.
• To assess the method's performance on synthetic and real pharmaceutical samples.

Main Methods:

• Optimization of partial least-squares (PLS) calibration parameters (wavelength range, number of factors).
• Validation of the optimized method using relative standard error (R.S.E.) and relative mean standard error (R.M.S.E.).
• Comparison with high-performance liquid chromatography (HPLC) for method validation.

Main Results:

• Optimal conditions were established for PLS calibration, minimizing R.S.E. and R.M.S.E.
• Synthetic mixtures were resolved with errors < 4.5% and relative standard deviations (R.S.D.) < 1.0%.
• The method demonstrated good agreement with HPLC results and performed well on pharmaceutical preparations.

Conclusions:

• The optimized PLS method provides accurate and precise resolution of DHZ-HCT binary and DHZ-HCT-reserpine ternary mixtures.
• The validated method is suitable for the analysis of pharmaceutical preparations.
• PLS chemometrics offers a robust approach for pharmaceutical mixture analysis.