LC-MS characterization of valsartan degradation products and comparison with LC-PDA

abstract Valsartan was submitted to forced degradation under acid hydrolysis condition as prescribed by the ICH. Degraded sample aliquots were separated via HPLC using a Hypersil ODS (C18) column (250 x 4.6 mm i.d., 5 µm). Either photodiode array (PDA) detection or mass spectrometry (MS) full scan monitoring of HPLC runs were used. HPLC-PDA failed to indicate Valsartan degradation under forced acid degradation, showing an insignificant peak area variation and that Valsartan apparently remained pure. HPLC-MS using electrospray ionization (ESI) and total ionic current (TIC) monitoring did not reveal any peak variation either, but inspection of the ESI mass spectra showed the appearance of m/z 306 and m/z 352 ions for the same retention time as that of Valsartan (m/z 436). These ions were identified as being protonated molecules of two co-eluting degradation products formed by hydrolysis. These assignments were confirmed by ESI-MS/MS with direct infusion of the degraded samples. The results showed that the use of selective HPLC-MS is essential for monitoring Valsartan degradation. Efficient HPLC separation coupled to selective and structural diagnostic MS monitoring seems therefore mandatory for comprehensive drug degradation studies, particularly for new drugs and formulations, and for method development.

resumo Valsartana (VAL) foi submetida à degradação forçada em meio ácido conforme procedimento descrito no ICH. Os produtos de degradação (PDs) foram monitorados ao longo do tempo de degradação pela técnica de Cromatografia Líquida (LC) utilizando uma coluna Hypersil ODS (C18) (250 x 4,6 mm d.i., 5 µm). A detecção foi feita com dois detectores: espectrofotométrico (PDA) e espectrometria de massas (MS) por corrente iônica total. Ambas as técnicas falharam na identificação dos PDs obtidos ao longo do monitoramento, mostrando insignificantes variações na área do pico e permanecendo com pureza de pico ao longo de toda a eluição. Somente depois da avaliação por íon extraído (XIC), foi possível observar o aumento do íon m/z 306 e m/z 352 exatamente no mesmo tempo de retenção do íon molecular (m/z 436). Estes resultados mostram um caso simples e didático em que somente o uso de um método seletivo de LC-MS pode ser utilizado para monitorar produtos de degradação. Neste trabalho, é apresentado um caso real em que a separação por LC deve ser acoplada a métodos seletivos obtidos por MS, especialmente no estudo de PDs para novos fármacos, formulações e no desenvolvimento de métodos.

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.

Modelos de avaliação da estabilidade de fármacos e medicamentos para a indústria farmacêutica / Stability models assessing of drugs and drug products for pharmaceutical industry

O estudo de estabilidade de fármacos e medicamentos, descrito pela resolução RE nº1/05 ANVISA determina a quantificação dos produtos de degradação, assim comoo método analítico utilizado correspondente. Como consequência, gerou-se a publicação do Informe Técnico nº 1/2008, com o objetivo de esclarecer procedimentos a serem realizados, nos casos em que a impureza ou padrões dos produtos de degradação não estão disponíveis. Diante das novas exigências, o delineamento do estudo torna-se uma das grandes dificuldades de sua realização, desafiando profissionais da área de desenvolvimento de produtos farmacêuticos.

The stability testing of drugs and medicines, as described in ANVISA resolution RE 1 / 05, specifies the quantitation of degradation products, as well as the analytical method concerned. As a consequence, Technical Report 1/2008 was published, with the aim of clarifying the procedures to be followed in cases where the impurity or patterns of degradation products are not available. In light of the new requirements, the study design constitutes one of the hardest problems for their implementation, facing professionals with new challenges in the area of pharmaceutical product development.