Crystalline oxybutynin and process for preparing the same

A crystalline oxybutynin free base, wherein the crystalline oxybutynin is characterized by an X-ray powder diffraction pattern having peaks at about 10.76 ±0.2, 18.079±0.2, 19.09±0.2, and 24.03±0.2 θ.

A process for the preparation of crystalline oxybutynin comprising the steps of:ni) providing oxybutynin acid addition salt in a solvent,ii) liberating the acid from its acid addition salt of oxybutynin by adjusting the pH employing a base; andiii) isolating the crystalline oxybutynin as its free base, wherein the crystalline oxybutynin is characterized by an X-ray powder diffraction pattern having peaks at about 10.76±0.2, 18.079±0.2, 19.09±0.2, and 24.03±0.2θ.

A process for preparation of crystalline oxybutynin comprising the steps of:ni) providing oxybutynin acid addition salt in a solvent;ii) liberating the acid from its acid addition salt of oxybutynin by adjusting the pH employing a base;iii) extracting the resultant oxybutynin free base employing an organic solvent;iv) concentrating the resultant extractions obtained in the above step (iii) to yield the crude residue of oxybutynin free base;v) treating the resultant residue of oxybutynin free base employing a non-polar solvent; andvi) isolating the pure crystalline oxybutynin as its free base, wherein the crystalline oxybutynin is characterized by an X-ray powder diffraction pattern having peaks at about 10.76±0.2, 18.079±0.2, 19.09±0.2, and 24.03±0.2 θ.

A process for preparation of crystalline oxybutynin base which comprises:n(i) condensing methyl phenylcyclohexylglycolate and 4-diethylamino-2-butynyl acetate; and(ii) isolating the crystalline oxybutynin base from the resultant reaction mass directly, wherein the crystalline oxybutynin base is characterized by an X-ray powder diffraction pattern having peaks at about 10.76±0.2, 18.079±0.2, 19.09±0.2, and 24.03±0.2 θ.