Sensitive Micellar Electrokinetic Chromatographic Determination of Salbutamol, Guaifenesin, and Dyphylline in Oral Formulations

Abstract

A sensitive micellar electrokinetic chromatographic method to analyze salbutamol, guaifenesin, and dyphylline employing 20 µm inner diameter capillaries was developed. Sensitive analysis of the drugs at a concentration range of about 0.5 to 60 µg/mL was demonstrated using large volume sample stacking with 75% acetonitrile as the sample diluent. Using dyphylline as the internal standard, detection limits were 0.07 µg/mL and 0.21 µg/mL for salbutamol and guaifenesin, respectively. Using the standard addition method, accurate determination of salbutamol and guaifenesin in syrup and capsule preparations was achieved. Recovery values were satisfactory (95 to 100%), but matrix interferences affected the reproducibility.

Keywords:

• Acetonitrile stacking
• Dyphylline
• Guaifenesin
• Large volume sample stacking
• Micellar electrokinetic chromatography
• Salbutamol

Notes

^a n = 3, constructed in terms of corrected peak area with 7 concentrations 1–70 µg/mL; Other conditions used were the same as in Figure 2a; corrected peak area = (peak area/migration time)_Analyte/(peak area/migration time)_{Internal Standard}.

^a Values are the mean values ± standard deviation; Concentration of control samples = 20 µg/mL.

^b Relative standard deviation.

^c Accuracy = (Mean measured value/Nominal value) × 100.

^a n = 4, concentration range of standard salbutamol added = 0–4 µg/mL.

^b n = 4, concentration range of standard guaifenesin added = 0–20 µg/mL.

^c versus calibration curve equation by external standard method y = 0.0463x +0.0394 from Table 1.

^d versus calibration curve equation by external standard method y = 0.0480x + 0.3098 from Table 1.

^a Average value, n = 3.

^b Values in parentheses are the accuracy of the measurement expressed in %.

^a Calculated from Table 4.

^b Average value ± standard deviation, n = 3.