(Received: June 6, 2006; Accepted: December 7, 2006)

ABSTRACT

   The aim of this study was to establish in vitro analytical methods for assessing an investigated oral BCG vaccine formulation.  In addition, in vivo immune response was also evaluated in guinea pigs by determining the potentially protective effect of the investigated formulation on tuberculosis.  The bicinchoninic acid (BCA) method for BCG protein quantitation was developed for rapid measuring the content of BCG vaccine in the investigated formulation.  The analytical method was conducted at 45°C to offer good precision (coefficient of variation <3.5%) and accuracy (error: -3.6~2.6%) in the range of 150~1000 μg/mL of BCG vaccine concentrations.  In the simulation study of drug release from the investigated formulation in the gastrointestinal tract under physiological conditions, the investigated oral formulation could protect active component at lower pH (0.1 N HCl) and completely release active component at higher pH (phosphate buffer, pH 6.8).  Although the investigated oral BCG vaccine formulation showed weak immune response to elicit IgG titer, the PPD (purified protein derivative) skin test in guinea pigs by oral dosing of 4 mg BCG vaccine formulation acquired about equal or higher response than that by 0.5 mg dose by subcutaneous vaccination.  The analytical method and in vivo approach could be further applied in the development of oral BCG vaccine formulations.