A sensitive, accurate and simple method using HPLC-MS/MS was developed and validated for levodopa quantitation in human plasma. Analysis was achieved on a pursuit® C18 analytical column (5 µm; 150 x 4.6 mm i.d.) using a mobile phase (methanol and water , 90:10, v/v) containing formic acid 0.5% v/v, after extracting the samples using a simple protein plasma precipitation with perchloric acid. The developed method was validated in accordance with ANVISA guidelines and was successfully applied to a bioequivalence study in 60 healthy volunteers demonstrating the feasibility and reliability of the proposed method.

Um procedimento é descrito para a determinação simultânea de substâncias androgênicas, incluindo esteróides e beta2-agonistas. O método envolve a análise de compostos anabólicos em urina hidrolisada, usando-se extração líquido-líquido com subseqüente conversão a derivados trimetilsililéteres, para análise por CG-EM. Injeção com divisão de fluxo de 1/10 dos derivados TMS a 280 °C, em uma coluna capilar, inicialmente mantida a 140 °C e então programada para 180 °C a 40 °C min-1, seguida por 3 ºC min-1 até 230 ºC, e então, 40 ºC min-1 até 300 ºC, resulta em uma boa resolução e formato de pico para todos os compostos. Os limites de detecção da maioria dos esteróides foi de 1 ng mL-1, exceto para a formebolona e trembolona (25 ng mL-1). Quando aplicado a amostras de urinas selecionadas com evidência de degradação bacteriana e metabólitos provenientes de medicação/vitaminas, o método permite a rápida triagem para androgênios e outras substâncias monitoradas em rotina. A resolução foi adequada para avaliar o perfil esteroidal endógeno, relevante para controle de dopagem e aplicações médicas.

A procedure is described for the simultaneous determination of androgenic substances including steroids and beta2-agonists. The method involves analysis of hydrolized urinary anabolic compounds using liquid-liquid extraction, with subsequent conversion to trimethylsilylether derivatives for the analysis by GC-MS. Pulse split injection 1/10 of the TMS derivatives at 280 °C into the capillary column, initially maintained at 140 °C then programmed to 180 °C at 40 °C min-1, followed by 3 ºC min-1 to 230 ºC and then 40 ºC min-1 to 300 ºC, resulted in good resolution and peak shape for all compounds. The detection limits of most of the steroids were 1 ng mL-1 except for formebolone and trenbolone (25 ng mL-1). When applied to selected urine samples with evidence of bacterial degradation and metabolites from usual medications/vitamins, the method allowed rapid screening for androgens and other substances monitored in routine. The resolution was adequate to evaluate the endogenous steroid profile relevant to doping control and medical applications.

Glucocorticosteroids (CT) show a powerful anti-inflammatory effect. In view of this, they are extensively used in sports medicine, but their misuse (systemic administration) can lead to severe injuries on athletes and has been restricted by the IOC in recent years. For GC-MS analysis, a derivatization step is necessary in order to convert them to a stable form, thus preventing thermal breakdown with the loss of the ketone side chain. Derivatization of CT is reviewed and a new approach of silylation is presented for screening of CT in urine.