Determination of prednisolone acetate, sulfacetamide and phenylefrine in local pharmaceutical preparations by micellar electrokinetic chromatography.

A new, rapid and simple method is described and applied to resolve and quantify mixtures of prednisolone acetate, sulfacetamide and phenylefrine. The determination was accomplished by micellar electrokinetic capillary chromatography (MEKC) using a fused silica capillary (57 cm x 75 microm ID). The separation was carried out at 25 degrees C and 30 kV, using a 5 mM phosphate-5 mM borate buffer adjusted to pH 8.2, 40 mM sodium dodecylsulfate (SDS) as background electrolyte. Under these conditions, the run time was 6.5 min and the limits of quantification were about 0.5 mg l(-1) for every component. Repeatability and reproducibility studies achieved were showing no significant differences at 95% confidence level. Then, multivariate calibration regression spectrophotometric methods (PLS-1, PLS-2 and PCR) were applied providing, especially PLS-1, a clear example of the high resolving power of these techniques. The MEKC method has been applied for quantifying these compounds in different commercial pharmaceuticals products and the method gave good results when it is compared with the spectrophotometric method. The pharmaceutical preparations do not require any separation step by the two described procedures.

Determination of prednisolone and the most important associated compounds in ocular and cutaneous pharmaceutical preparations by micellar electrokinetic capillary chromatography.

A micellar electrokinetic capillary chromatographic method to separate prednisolone, prednisolone acetate, naphazoline, Zn-bacitracin, sulfacetamide and phenylefrine is described. The separation was carried out by using a fused-silica capillary (57 cmx75 micrometer I.D.) at 25 degrees C and 30 kV, using a 5 mM phosphate-5 mM borate buffer adjusted to pH 8.2, 50 mM sodium dodecyl sulfate (SDS) and 10% methanol-water (v/v) as background electrolyte. Under these conditions, the run time was 8 min and the limits of quantification were about 1.0 mg/l for every component. The method was applied to pharmaceutical preparations and the results provided recoveries close to 100% and the method gave good results when compared with a reference multivariate calibration spectrophotometric method.

Simultaneous determination of dexamethasone and trimethoprim by liquid chromatography.

A reverse phase high performance liquid chromatography (HPLC) method to determine dexamethasone phosphate and trimethoprim is described in this paper. The separation was made in a LichrCART(R) C18 column using an acetonitrile-NaH(2)PO(4) (10 mM) (70:30, v/v) (pH 3) buffer solution as mobile phase. The mobile-phase flow rate and the sample volume injected were 1 ml/min and 20 microliter, respectively. The limits of quantification were about 0.25 mg/l for each compound. The method was applied in synthetic mixtures and in pharmaceutical formulations. Analyses were made by preparing test (from the stock solution) method whose results were compared with those obtained by means of the standard addition method. Both methods showed similar results, and then it was proved that some pharmaceuticals claimed levels were in agreement with the obtained results by using our analytical method.

Comparison of HPLC and multivariate regression methods for hydrocortisone and lidocaine analysis of pharmaceutical preparations.

A reverse-phase high-performance liquid chromatographic (HPLC) method to determine hydrocortisone acetate, hydrocortisone hemisuccinate and lidocaine is described in this paper. The separation was made in a LichrCART C(18) column using a methanol-NaH(2)PO(4)/Na(2)HPO(4) (0.1 mol L(-1)) (pH=4.5) buffer solution as a mobile phase in isocratic mode (60:40 (v/v)). The mobile phase flow rate and the sample volume injected were 1 mL min(-1) and 20 micro L, respectively. The detection was made with a diode-array detector measuring at the maximum for each compound. Quantification limits ranging from 0.18 to 0.84 micro g L(-1) were obtained when the peak area was measured. The method was applied in pharmaceutical formulations that were compared with those obtained by through multivariate regression spectrophotometry and micellar capillary electrophoresis (MEKC). HPLC results are in accordance with the results obtained by MEKC. The spectrophotometric method was suitable only for synthetic samples.

Micellar electrokinetic capillary chromatography as an alternative method for the determination of dexamethasone, trimethoprim, and polymyxin B.

A micellar electrokinetic capillary chromatographic method is presented which enables quantification of dexamethasone, polymyxin B and trimethoprim in synthetic mixtures and pharmaceutical products. Separation was carried out at 25 degrees C and 30 kV, with 10 mmol L(-1) borate-phosphate buffer adjusted to pH 8 as electrolyte, with 50 mmol L(-1) sodium dodecyl sulfate. Under these conditions separations were performed in 10 min. The limits of detection and quantification were approximately 2 mg L(-1) for each component, except for polymyxin B. The method was applied to different commercial formulations.