A preformulation study was performed for the evaluation of a vaccine candidate against HIV-1. Aluminium hydroxide was used in the preformulation. However, this adjuvant is not a good adsorbent for basic proteins since it is positively charged at a physiological pH. In the present study, we determined the adsorption of TAB9 (basic protein, pI: 11.3) by treating Alhydrogel with different ions. The immunogenicity of the vaccine candidate against HIV was also evaluated using three batches, 9801-A, 9802-A and 9803-A, and a placebo P-001. The evaluation was performed twice (0 and 9 months). Each batch was tested using groups of 10 mice that had a single inoculation. The results showed that the protein was totally adsorbed to the aluminium gel. Seroconvertion was attained in all analysed batches, indicating the potentiality of TAB9 as a vaccine candidate.