Resumo

ALEMON-MEDINA, Radamés et al. Physicochemical stability of a metformin solution from three commercial brands. Acta pediatr. Méx [online]. 2014, vol.35, n.2, pp.104-110. ISSN 2395-8235.

Pharmacological management of insulin resistance and dyslipidaemias in children and adolescents is required to prevent the development of metabolic syndrome (MS) and type II diabetes mellitus (DM2). Material and method: we developed extemporaneous formulations from 500 mg-tablets from three generic brands, commercially available in Mexican drugstores: Medimart™, Farmacias del Ahorro™ and Primer Nivel™, dissolved in water sweetened with Splenda, which made them palatable and allowed customised dose adjustment. Solutions were stored at four environmental conditions: 25°C exposed to light, 25°C protected from light, 4°C and 40°C, and their physicochemical stability was assayed. The stability of the drug was determined by ultra performance liquid chromatography and ultraviolet detection (UPLC-UV) and by measuring the pH of the stock solution. The mobile phase consisted of (KH₂PO₄) 0.1 M, pH = 6.5, 4.6 mM sodium dodecyl sulphate (SDS) and acetonitrile (63:7:30) at 0.8 mL/min, column VARIAN Pursuit C8 150 × 3.9 mm tempered at 40°C, with detection at 236 nm. Results: Metformin from all trademarks was stable at all storage conditions for up to 30 days, retaining more than 90% of the initial amount of active drug, with a pH of 7.4 ± 0.3. Conclusion: Metformin extemporaneous formulations may be developed from either the innovator or generic brands, having the advantage of saving money and conserving the stability of its physicochemical properties.

Palavras-chave : Generic metformin; Innovator metformin; Extemporaneous formulation; Physicochemical stability; UPLC-UV.