PCT Application for Ritonavir Polymorph Enters Indian National Phase

Illinois-based healthcare company Abbott Laboratories has lately filed a National Phase Application # 1638/MUMNP/2007A for a new crystalline polymorph of Ritonavir, maturing from its PCT Application # PCT/1999/16334 published as WO 2000/004016 (the ‘016 publication) dated January 27, 2000. The National Phase Application claims its earliest priority from the US Application # 09/119,345 filed July 20, 1998. The ‘016 publication claims a crystalline polymorph (designated as Form II), a substantially pure amorphous form of Ritonavir and processes for the preparation. The crystalline Form II is obtained by treating amorphous Ritonavir with a C1-C3 alcohol, preferably anhydrous alcohol, or by recrystallization of Form I or mixtures of Form I and Form II from a solution in a suitable solvent, with seeding with Form II crystals, followed by addition of an anti-solvent. The substantially pure amorphous form is prepared from the Form I crystalline polymorph by melting Form I and rapidly cooling the melt, isolating the resulting solid provides amorphous Ritonavir, or by slowly adding a solution of Form I in a suitable solvent to an anti-solvent/water, followed by isolation of the resulting solid, or by lypophilization of a solution of Form I. The National Phase Application is divisional application of earlier filed National Phase Application # IN/PCT/2001/0018/MUMA. It seems to be that Abbott bifurcated crystalline polymorph of Ritonavir and Substantially pure amorphous Ritonavir into two applications.