Parenteral adjuvant potential of recombinant B subunit of Escherichia coli heat-labile enterotoxin

BACKGROUND The B subunit of Escherichia coli heat-labile enterotoxin (LTB) is a potent mucosal immune adjuvant. However, there is little information about LTB's potential as a parenteral adjuvant. OBJECTIVES We aimed at evaluating and better understanding rLTB's potential as a parenteral adjuvant using the fused R1 repeat of Mycoplasma hyopneumoniae P97 adhesin as an antigen to characterise the humoral immune response induced by this construct and comparing it to that generated when aluminium hydroxide is used as adjuvant instead. METHODS BALB/c mice were immunised intraperitoneally with either rLTBR1 or recombinant R1 adsorbed onto aluminium hydroxide. The levels of systemic anti-rR1 antibodies (total Ig, IgG1, IgG2a, and IgA) were assessed by enzyme-linked immunosorbent assay (ELISA). The ratio of IgG1 and IgG2a was used to characterise a Th1, Th2, or mixed Th1/Th2 immune response. FINDINGS Western blot confirmed rR1, either alone or fused to LTB, remained antigenic; anti-cholera toxin ELISA confirmed that LTB retained its activity when expressed in a heterologous system. Mice immunised with the rLTBR1 fusion protein produced approximately twice as much anti-rR1 immunoglobulins as mice vaccinated with rR1 adsorbed onto aluminium hydroxide. Animals vaccinated with either rLTBR1 or rR1 adsorbed onto aluminium hydroxide presented a mixed Th1/Th2 immune response. We speculate this might be a result of rR1 immune modulation rather than adjuvant modulation. Mice immunised with rLTBR1 produced approximately 1.5-fold more serum IgA than animals immunised with rR1 and aluminium hydroxide. MAIN CONCLUSIONS The results suggest that rLTB is a more powerful parenteral adjuvant than aluminium hydroxide when administered intraperitoneally as it induced higher antibody titres. Therefore, we recommend that rLTB be considered an alternative adjuvant, even if different administration routes are employed.

Avaliação do processo de partição em comprimidos de hidroclorotiazida / Assessment of the splitting process in hydrochlorothiazide tablets

Um dos problemas mais comuns para a saúde da população é a hipertensão arterial, uma doença cardiovascular, cujas consequências podem ser fatais. Esta patologia requer tratamento posológico rigoroso para manutenção da concentração plasmática do fármaco em níveis terapêuticos desejados e constantes, para o devido controle da pressão arterial. Um dos fármacos mais utilizados para o controle da hipertensão é o diurético hidroclorotiazida. O presente estudo teve como objetivo avaliar o processo de partição (divisão em duas partes) em comprimidos de hidroclorotiazida, através de ensaios físico-químicos. Foram avaliadas as apresentações similar (S), genéricos (G) e referência (R) do fármaco estudado. Os resultados obtidos demonstraram que essa prática não se mostra segura, em função das grandes variações, na concentração de fármaco, encontrados em cada uma das partes do comprimido.

One of the commonest problems affecting the health of the population is arterial hypertension, a cardiovascular disease, whose consequences can be fatal. This condition requires strictly controlled drug dosage to maintain the plasma concentration of the drug at desirable and constant therapeutic levels, in order to control the blood pressure. One of the drugs most used for arterial hypertension control is the diuretic, hydrochlorothiazide. The aim of this study was to assess, by means of physicochemical tests, the process of splitting hydrochlorothiazide tablets into two parts. Similar (S), generic (G) and reference (R) forms of the drug were tested. The results showed that this practice appears not to be safe, according to the wide variations in the amount of drug found in each part of the tablet.