Patent ID: 7632853

Claim:
A process for preparing a pharmaceutical composition of ritonavir comprising the following steps: (a) dissolving from 10% to 30% by weight of the final pharmaceutical composition of ritonavir in sufficient amount of an alcohol solvent of C 2 -C 4 to obtain a clear solution, at a temperature between 30° C. and 45° C. to make a first mixture; (b) eliminating particles from said first mixture by filtration; (c) evaporating the alcoholic solvent from the filtered first mixture under reduced pressure at a temperature not higher than 40° C. to about half of its initial volume; (d) adding to the filtered and concentrated first mixture an alcoholic co-solvent in an amount of 10% by weight of the final pharmaceutical composition, a medium chain mono/diglycerides mixture in an amount ranging from 20% to 40% by weight of the final pharmaceutical composition, an antioxidant in an amount ranging from 0.01% to 0.1% by weight of the final pharmaceutical composition, an emulsion-stabilizing agent in an amount up to 60% by weight of the final pharmaceutical composition and a polarity corrector in an amount up to 0.5% by weight of the final pharmaceutical composition to make a second mixture; (e) removing the alcoholic solvent of step (a) from said second mixture by distilling under reduced pressure to correct the weight of said second mixture until the remaining quantity of alcoholic solvent is of 12% by weight of the final pharmaceutical composition; (f) adding to the distilled second mixture a surfactant in an amount ranging from 5% to 10% by weight of the final pharmaceutical composition under continuous stirring, until the second mixture becomes a clear solution, thereby obtaining a stable and concentrated ritonavir pharmaceutical composition; and (g) correcting, if necessary, the final weight of the final pharmaceutical pharmaceutical composition by adding the alcoholic solvent employed in the step (a) to obtain a solution comprising from 10% to 30% by weight of the final pharmaceutical composition of ritonavir.