| abstract |
Formation and simultaneous encapsulation of small particles of organic compounds, e.g. pharmaceutically active compounds, whose solubility in water is greater at a first pH than at a second pH. In one embodiment, the organic compound is dissolved in water in the presence of sufficient base to raise the pH to the first pH and at least 2 pH units above the pKa of the compound, together with an encapsulating material and an electrolyte effective (but present in an amount just insufficient) to cause coacervation of the encapsulating material without interacting with it, stirring and titrating the solution with a titrant effective to lower the pH of the solution to the second pH to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material, and gelling the encapsulating material. |