Development and validation of a repharsed phase- HPLC method for simultaneous determination of rosiglitazone and glimepiride in combined dosage forms and human plasma

Abstract

Background: Rosiglitazone (ROZ) and glimepiride (GLM) are antidiabetic agents used in the treatment of type 2 diabetes mellitus. A survey of the literature reveals that only one spectrophotometric method has been reported for the simultaneous determination of ROS and GLM in pharmaceutical preparations. However the reported method suffers from the low sensitivity, for this reason, our target was to develop a simple sensitive HPLC method for the simultaneous determination of ROZ and GLM in their combined dosage forms and plasma.

Results: A simple reversed phase high performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous determination of Rosiglitazone (ROS) and Glimepiride (GLM) in combined dosage forms and human plasma. The separation was achieved using a 150 mm × 4.6 mm i.d., 5 μm particle size Symmetry® C18 column. Mobile phase containing a mixture of acetonitrile and 0.02 M phosphate buffer of pH 5 (60: 40, V/V) was pumped at a flow rate of 1 mL/min. UV detection was performed at 235 nm using nicardipine as an internal standard. The method was validated for accuracy, precision, specificity, linearity, and sensitivity. The developed and validated method was successfully used for quantitative analysis of Avandaryl™ tablets. The chromatographic analysis time was approximately 7 min per sample with complete resolution of ROS (tR = 3.7 min.), GLM (tR = 4.66 min.), and nicardipine (tR, 6.37 min). Validation studieswas performed according to ICH Guidelines revealed that the proposed method is specific, rapid, reliable and reproducible. The calibration plots were linear over the concentration ranges 0.10-25 μg/mL and 0.125-12.5 μg/mL with LOD of 0.04 μg/mL for both compounds and limits of quantification 0.13 and 0.11 μg/mL for ROS and GLM respectively.

Conclusion: The suggested method was successfully applied for the simultaneous analysis of the studied drugs in their co-formulated tablets and human plasma. The mean percentage recoveries in Avandaryl™ tablets were 100.88 ± 1.14 and 100.31 ± 1.93 for ROS and GLM respectively. Statistical comparison of the results with those of the reference method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods respectively. The interference likely to be introduced from some co-administered drugs such as glibenclamide, gliclazide, metformine, pioglitazone and nateglinide was investigated.

Figure 1

Structural formulae of the studied drugs.

Figure 2

Typical chromatogram of glimepiride (12.5 μg mL^-1), rosiglitazone (25 μg mL^-1) and nicardipine HCl (20 μg mL^-1) using acetonitrile/0.02 M phosphate buffer of pH 5 (60: 40, V/V) as a mobile phase.

Figure 3

Effect of acetonitrile: phosphate buffer ratio (pH 5.0) on the resolution of GLM (12.5 μg mL^-1) and ROS (25 μg mL^-1) using the proposed HPLC method.

Figure 4

Effect of pH on the resolution of GLM (12.5 μg mL^-1) and ROS (25 μg mL^-1) using the proposed HPLC method.

Figure 5

Typical chromatogram for: (A): Blank plasma (B): ROS (1 μg mL^-1), GLM (1 μg mL^-1) and NIC (2 μg mL^-1) in spiked human plasma.