Desenvolvimento e avaliação de estabilidade de suspensão oral de sulfadiazina para uso em pediatria

Abstract

Toxoplasmosis is a disease caused by Toxoplasma gondii (T. gondii), a protozoan belonging to the Apicomplexa phylum, where the intermediate, or incomplete, hosts are the mammals and the birds and the definitive, or complete, hosts are the cats. The form of intrauterine transmission of this zoonosis is quite serious, increasing the gravity the younger the fetus. Toxoplasmosis has worldwide geographical distribution and high prevalence, being considered the most widespread zoonosis in the world. The protocol for the treatment of children with congenital toxoplasmosis, suspected or confirmed, should be performed from birth using the association scheme sulfadiazine and pyrimethamine combined with folinic acid. In the context of treatment of toxoplasmosis in Brazil, these medicines do not have appropriate pediatric pharmaceutical form. The present task aimed to develop a formulation of one of the drugs, sulfadiazine, in the pharmaceutical form of oral suspension, considering the necessity and inexistence of this product for pediatrics in the treatment of toxoplasmosis in the Brazilian market. In this context, the formulation was developed from the grinding of tablets of the reference drug Suladrin® suspended in the vehicle GUTE, this one developed in the laboratory of Pharmacotechnics of the UFC. The sulfadiazine suspension was evaluated for 93 days under the quality parameters: formulation appearance, constituent microscopic particles, relative density (picnometry), rheological behavior and viscosity, sedimentation rate, pH and sulfadiazine dosing (UV spectrophotometry). The formulation of the proposed oral suspension of sulfadiazine, generally exhibited ease in preparation and handling. Acid character, density, characterization of microscopic particles, rheological behavior characterized as non-newtonian psedoplastic fluid and sedimentation velocity were characterized did not present measurable modifications, since, during the evaluation period, the initial characteristics were maintained, giving the formulation quality from the standpoint of physical and chemical stability. The UV spectrophotometry method used for the determination of sulfadiazine in the formulation presented linearity, with correlation factor (R2) 0.9991 and specificity, and it was concluded that the other constituents of the employed vehicle GUTE do not interfere in the detection of the asset. It was possible to estimate the validity period of 60 days for the developed formulation, this period is comparatively more advantageous than those usually used in public hospitals