Valuation of environmental influence of recently invented high-performance liquid chromatographic method for hypoglycemic mixtures of gliflozins and metformin in the presence of melamine impurities: Application of molecular modeling simulation approach

Molecular modeling is the science of representing molecular structures numerically and simulating their behavior with the equations of quantum and classical physics. Coupling molecular modeling and simulation with chromatographic resolution for pharmaceutical products constitutes a new technique in pharmaceutical analysis. An innovative high-performance liquid chromatographic (HPLC) methodology was developed for the quantification of metformin hydrochloride (MET), empagliflozin (EMP), and canagliflozin (CAN) in bulk, laboratory-developed combinations, pharmaceutical tablets, and in the presence of melamine. Chromatographic separation was accomplished using a Symmetry column with 0.03 M potassium dihydrogen phosphate buffer and 0.02 M heptane sulphonic acid: acetonitrile as the mobile phase. Molecular modeling using molecular operating environment software was applied to properly select the stationary phase suitable for the developed HPLC method. Additionally, molecular modeling estimates and validates binding between the studied analytes and the stationary phase to clarify and explain the chromatographic separation and elution order. In accordance with the International Conference of Harmonization recommendations, the method was validated in terms of linearity, accuracy, precision, and selectivity. The linearity ranges (μg/ml) were 200-1500 (MET), 2-15 (EMP), and 20-150 (CAN) and the limit of detection values were in the ranges of 0.17-54.58 μg/ml. Analysis of pharmaceutical tablets using the suggested approach yielded satisfactory outcomes. As a result, it might be used in quality control laboratories to analyze the aforementioned medications.

Cytochrome P450 3A4-mediated pharmacokinetic interaction study between tadalafil and canagliflozin using high-performance thin-layer chromatography

Diabetes is a known risk factor for sexual dysfunction in men; diabetic men have an increased risk of erectile dysfunction compared to non-diabetic men. Canagliflozin is one of the common antidiabetic drugs that is readily used in the treatment of type-2 diabetes. Concomitantly phosphodiesterase 5 inhibitors, such as tadalafil, can be given to the patient to alleviate erectile dysfunction. Canagliflozin is reported to be one of the cytochrome P450 3A4 enzyme inhibitors, that might seriously influence blood concentration levels of tadalafil but there is no study till now, discussing this interaction. Therefore, a fast, simple, and sensitive high-performance thin-layer chromatographic method was developed, validated, and applied for the simultaneous determination of tadalafil and canagliflozin in spiked and real human plasma. The limit of detection for tadalafil was 0.14 ng/band and for canagliflozin was 0.16 ng/band. The limit of quantitation value for tadalafil was 0.43 ng/band and for canagliflozin was 0.47 ng/band. Tadalafil and canagliflozin were determined simultaneously in real human plasma using the described procedure and the method was applied for in vivo pharmacokinetic drug interaction study between the studied drugs, which proved significant interaction between them when administered simultaneously.

Application of experimental design in HPLC method optimization and robustness for the simultaneous determination of canagliflozin, empagliflozin, linagliptin, and metformin in tablet

Gliflozins and gliptins represent two different pharmacological drug classes that exert different and potentially complementary glucose-lowering effect in patients with type II diabetes mellitus. A novel, selective, and sensitive HPLC method was developed for the determination of canagliflozin, empaglifozin, linagliptin, and metformin in pure form, in laboratory prepared mixtures, and in pharmaceutical dosage form. Experimental design optimization was applied by using Plackett-Burman and face-centered composite designs to achieve the best resolution with minimum experimental trials. Three significant variables affecting optimization, namely buffer pH, percentage of methanol, and percentage of acetonitrile, were studied. Chromatographic separation was achieved using an Agilent Eclipse C₈ column, and column temperature was kept at 45°C. The mobile phase was composed of dipotassium hydrogen phosphate buffer (0.05 M, adjusted to pH 6 using o-phosphoric acid):acetonitrile:methanol (50:25:25, v/v/v) at a flow rate of 1.5 mL/min. Sharp and well-resolved peaks of the cited drugs were obtained. The method was fully validated in terms of linearity, accuracy, precision, selectivity and robustness in agreement with the International Council of Harmonization (ICH) guidelines Q2 (R1). Satisfactory results were obtained by the analysis of tablets through applying the developed method. Therefore, it could be performed for the analysis of the cited drugs in quality control laboratories.