The application of solid dispersion technique in the preparation of therapeutic tablets. Part 1: Paracetamol, amylobarbitone, and caffeine tablets.

: A trial was made to study the possibility of preparing high-quality therapeutic tablets by direct compression of the solidified drugcarrier melt via solid dispersion technique. Paracetamol-mannitol, amylobarbitone-urea and caffeine-nicotinamide systems were investigated. Phase diagrams of the first two systems were found to be of the simple eutectic type, while that of the third system was a peritectic type. Solubility studies were also carried out. Dissolution rate studies showed that the fused mannitol/paracetamol (80:20), urea/amylobarbitone (80:20) and nicotinamide/caffeine (50:50 and 70:30) solid dispersions exhibited better rates of dissolution than those of the pure drugs. Comparative studies were carried on with tablets prepared by direct compression of the drug-carrier solidified melt exhibiting the highest dissolution rate and by slugging the pure drug and the drug-carrier physical mixture of corresponding composition. The physical properties and dissolution rate data showed the superiority of the tablets prepared by the solid dispersion technique. The drug release from these tablets was 4.5, 7.6 and 3.7 times greater than that from tablets prepared from pure paracetamol, amylobarbitone and caffeine respectively.