Najma Sultana, Safila Naveed* and M Saeed Arayne
The association between the use of ACE inhibitors and the incidence of hypoglycemia is controversial.
A recent study reported that 14% of all hospital admissions for hypoglycemia might be attributable to ACE
inhibitors. In this paper, a novel, precise, specific, accurate and rapid reversed-phase high performance liquid
chromatographic method was developed, optimized and validated for determining captopril and hypoglycemic
(metformin, pioglitazone and glibenclamide) in bulk, pharmaceutical formulations and human serum with the best
chromatographic peak resolution, reduced run time and low cost of analysis. The method was validated according
to the US Food and Drug Administration (FDA) and ICH guidelines for the parameters: specificity, stability, limits
of detection (LLOD), limits of quantification (LLOQ), linearity, accuracy, precision and recovery. This method
showed the best resolution by using Hypersil ODS,C18 (150Ã4.6 mm, 5 micron) column using mobile phase,
methanol: water (70: 30 v/v) adjusted to pH 3 via ortho phosphoric acid 85% with flow rate of 1 mLmin-1 at ambient
temperature and wavelength of 230 nm. The signal-to-noise ratio (S/N) was employed as a quality measurement.
This tool permits to establish the influence of some selected factors (methanol: water ratio, pH, and flow rate) on
two responses (peak areas and retention time). The LLOD and LLOQ values for CAP, MET, PGL and GLB were
found to be 2.3, 1.5, 2.3 and 2.3 and 0.7, 0.4, 0.7, and 0.7 μgmL-1 respectively. Calibration curves were linear in
the concentration range of 2.5-100 μgmL-1 for hypoglycemic and captopril with regression coefficient (r
2
) value of
0.999 for all drugs. The data for accuracy, precision and recovery were within the FDA limits. Intra ad inter-day
precision and accuracy results were 98.0 to 102%. Retention time for captopril was found to be 3.3 minute and
for metformin, pioglitazone and glibenclamide 2.4, 2.8, 7.2 minutes respectively. Proposed method was selective,
precise and accurate short time analysis therefore can be used for routine, quality control and clinical study.
This is the first full report of a method for the simultaneous determination of these four drugs: captopril,
metformin, pioglitazone and glibenclamide in API, formulations and serum. The newly developed method is useful for
future routine analysis of these drugs and could be used in therapeutic drug monitoring and adherence to medicine
studies, which would be helpful in decision making regarding treatment change in combination therapies.