Validation of new analytical methodology for determining fenoterolhydrobromide by HPLC: application in pharmaceutical products

Fenoterol hydrobromide is a B2-adrenergic agonist agent used for asthma and chronic obstructive pulmonary disease treatment. HPLC methodology was developed and validated for quantitative determination of fenoterol hydrobromide. The methodology was achieved by using a reversed-phase C18column, (150 mm ¡Á 3.9 mm i.d., 5 ¦Ìm) Thermo. The mobile phase was consisted of acetonitrile: water(30:70, v/v) with 0,1% triethylamine, pH adjusted to 5.0 with formic acid and flow rate of 1.0 mL.min-1with UV detection at 276 nm. The concentration range was from 0.025 to 0.15 mg.mL-1, and the correlation coefficient of analytical curve was >0.999. The detection limit and the quantifying limit (QL) were 0.003mg.mL-1 and 0.012 mg.mL-1, respectively. Intra- and interday relative standard deviations were ¡Ü2.0%. Themetho dology accuracy showed the percentage mean of 99.53%. The described technique was found to be simple, rapid, precise, accurate and sensitive; the advantages over the others current methodologies arethe low-cost and low-polluting conditions. Owing to its simplicity and reliable results, this methodology is suitable to be used in quality control of pharmaceutical drugs containing fenoterol hydrobromide as active componente.

Determinação espectrofotométrica do bromidrato de fenoterol em preparações farmacêuticas / Spectrophotometric determination of fenoterol hydrobromide in pharmaceutical preparations

Um método espectrofotométrico simples foi desenvolvido para a determinação do bromidrato de fenoterol (BF) em comprimidos, gotas e xarope, como princípio ativo único e associado aoibuprofeno. O método se baseia na reação de acoplamento oxidativo do BF com o 3-metil-2-benzotiazolinona hidrazona (MBTH), na presença de sulfato cérico, como agente oxidante. Amistura de BF, MBTH e sulfato cérico, em meio ácido, produz um composto colorido (vermelho castanho) com máximo de absorção a 475 nm. A curva de calibração foi linear num intervalo deconcentração de 3,0 a 12,0 μg/mL, com coeficiente de correlação linear de 0,9998. Os parâmetros experimentais que afetam o desenvolvimento e a estabilidade do produto colorido foramcuidadosamente estudados e otimizados. O método foi aplicado em amostras comerciais e simuladas, obtendo-se coeficientes de variação entre 0,25 % a 0,82 % e médias de recuperação do padrão que variaram de 98 % a 102 %. O método proposto mostrou-se exato, preciso, linear e não é passível de interferência de excipientes, para as formas farmacêuticas comprimidos e gotas. Não houve interferência do ibuprofeno que consta de uma dasformulações analisadas, associado ao BF. Quanto ao xarope, houve interferência do veículo sugerindo reações de seus componentes com o MBTH.

A simple spectrophotometric method has been developed for the determination of fenoterol hydrobromide (FH) in TABELA IV - Valores obtidos em termos de fatores de resposta (FR), considerando a concentração de BF e respectivas absorvâncias determinadas em 475 nm, a partir do placebo da amostra B. Os valores expressam a média de três determinações Concentração Concentração Absorvância Fator deteórica encontrada Resposta (μg/mL) (μg/mL) (FR) 6,0 5,93 0,4895 0,082557,0 6,89 0,5633 0,08176 8,0 8,12 0,6571 0,08092 9,0 9,09 0,7471 0,08219 10,0 10,04 0,8144 0,08112FR médio = 0,08171; DP = 0,0006912; CV = 0,85%. tablets, drops and syrup, as the only active principle andassociated with ibuprofen. The method is based on the oxidative coupling reaction of the FH with 3-methyl-2-benzothiazolinone hydrazone (MBTH) and ceric sulphate as oxidant reagent. The mixture of the drug, MBTH andceric sulfate, in acid medium, produces a red brown color compound, with absorption maximum at 475 nm. Thecalibration curve was linear over a concentration range from 3.0 to 12.0 μg/mL, with correlation coefficient of0.9998. The different experimental parameters affecting the development and stability of the color compound werecarefully studied and optimized. The method was applied successfully to assay FH in dosage forms and simulatedsamples. The coefficient of variation was from 0.25 % to 0.82 % and average recoveries of the standard from 98 % to 102 %. The excipients (tablets and drops) did not interfere in the analysis and the results showed that method can be used for determination of the FH isolated or associated with ibuprofen with precision, accuracy and specificity. In case of syrup, the interference in the analysis suggests apossible reaction between vehicle components with MBTH.