No abstract

A new, rapid, and simple method is described and used to resolve and quantify mixtures of prednisolone, naphazoline, and phenylephrine. The determination was accomplished by micellar electrokinetic chromatography (MEKC) using a fused-silica capillary (57 cm675 lm ID). The separation was carried out at 258C 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 6.6 min and the limits of quantification were about 0.4 mg/L for every component. Repeatability and reproducibility studies showed no significant differences at 95% confidence level. Application of multivariate calibration regression spectrophotometric methods (PLS-1, PLS-2, and PCR) clearly demonstrated, especially in the case of PLS-1, the high resolving powder of these techniques if all possible interferences are suppressed. MEKC has been used for quantifying these compounds in different pharmaceutical products and the method gave good results compared with spectrophotometry. The pharmaceutical preparations do not require any separation steps when analysed by the two procedures described.

No abstract

SummaryA new, simple, and accurate micellar electrokinetic chromatographic (MEKC) method is clescribed for quantification of hydrocortisone, hydrocortisone hemisuccinate, hydrocortisone acetate, nystatin, oxytetracychne, Zn-bacitracin, polymyxin B, and hdocaine in ocular and cutaneous pharmaceutical products. The separation was performed at 25 ~ and 25 kV, with 15 mM phosphate + 15 mM borate buffer, pH 8.2, and 60 mM sodium dodecylsulfate (SDS) in 10:1 (%, v/v) methanol-water as background electrolyte. Under these conditions the analysis time is approximately 23 min. The method has been used for quantification of these compounds in different commercial pharmaceutical products and gave good results when compared with reference spectrophotometric and HPLC methods.