Desenvolvimento e validação de métodos físico-químico e microbiológico para doseamento de espiramicina em comprimidos.

Abstract

Antibiotics are drugs of great importance in therapy and deserve to be highlighted in analytical studies. Among them, the macrolides have bacteriostatic and bactericidal action. Spiramycin is a drug belonging to this class and is commercialized in some countries, including Brazil, where it was recently registered. The reference medicine is found commercially in the form of tablets. Quality assurance is extremely relevant to the effectiveness of the medication during treatment. Thus, the objective of this work was to develop and validate methods for quantification of spiramycin in tablets by high performance liquid chromatography and microbiological potency assay. For development and optimization of the chromatographic method, different conditions were initially tested using the 2 3 full factorial design, in which different proportions of methanol in mobile phase, mobile phase flow rates and oven temperatures were tested. Then, optimization of the chromatographic parameters was made using the Doehlert Matrix and response surface methodology, in order to obtain fast and efficient separation for spiramycin I in relatively short retention time. In addition, more ecofriendly solvents were used, which favors the use of the method in the quality control routine. The method was validated using phosphoric acid 0.1% v/v in HPLC water and methanol (67:33, v/v) as a mobile phase, flow rate at 1.0 mL.min-1 , NST C-8 analytical column (250 mm x 4.6 mm, 5 µm) as a stationary phase, detection at 232 nm and injection volume of 20 µL. The analytical method was selective, with no excipients interfering in the quantification, linear (r = 0.9997), precise (RSD < 2,5%), accurate (98,5- 101,0%) and robust. The limits of detection and quantification were 1,61 µg.mL-1 and 4,88 µg.mL-1 , respectively. The microbiological assay by agar diffusion was developed and validated according to the guidelines of the International Council of Harmonization, United States Pharmacopoeia 40th edition and some studies from literature. The method proved to be selective against the excipients (p > 0,05), linear (r = 0,9997), precise (RSD < 2,0%) and accurate.. Futhermore, it was possible to measure the potency of the antibiotic using the method developed.