Patent ID: 8227483

Claim:
A crystalline form of 6-beta-naltrexol base, morpnhinan-3,6,14-trio,17-(cyclopropvlmethyl)-4,5-epoxy chosen from Form I B and Form II B , wherein the crystalline form is chosen from the following group: i. Form I B , which exhibits an X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2-theta at about 9.8, about 14.0, about 15.9, about 17.2, about 17.7, and about 22.4; ii. Form I B , which exhibits a differential scanning calorimetry profile having a endotherm/exotherm from about 75°-125° C. and an endotherm at about 185°-190° C.; iii. Form I B , which exhibits a thermogravimetric analysis showing a loss of mass of about 4.0-6.0% from about 75°-160° C.; iv. Form II B , which exhibits an X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2-theta at about 10.9, about 15.6, about 16.5, about 17.2, and about 18.7; v. Form II B , which exhibits a differential scanning calorimetry profile having an endotherm/exotherm from about 90°-110° C. and an endotherm at about 189°-190° C.; and vi. Form II B , which exhibits a thermogravimetric analysis showing a loss of mass of about 0.2-0.3% from about 75°-125° C.