| abstract |
Atorvastatin calcium, a substance known by the chemical name (R- (R *, R *)) - 2- (4-fluorophenyl) -β, δ-dihydroxy-5- (1-methylethyl) -3-phenyl - ((phenylamino) ) carbonyl) -1H-pyrrole-1-heptanoic acid, a hemi calcium salt, is known as an HMG-CoA reductase inhibitor and is used as an antihyper-cholesterolemic agent. Atorvastatin in commercially available pharmaceutical compositions is generally prepared in the form of its calcium salt, since it allows atorvastatin to be suitably formulated in pharmaceutical formulations, for example, in tablets, capsules, powders and similar formulations for oral administration. Atorvastatin calcium may exist in amorphous form or in one of at least four known crystalline forms (Form I, Form II, Form III and Form IV). Atorvastatin calcium is a substance that is moderately poorly soluble in water, with a pKa of 4.5, and it has been determined that the crystalline forms are less soluble than the amorphous form, which can cause problems in the bioavailability of atorvastatin in the body. The present invention solves the problem of providing therapeutic equivalence of the pharmaceutical formulation of atorvastatin, regardless of the form (crystalline, amorphous or a mixture of both) of atorvastatin calcium, which is used for its preparation. |