Patent ID: 8501227

Claim:
A method for stabilizing solid bupropion pharmaceutical preparations by preventing direct contact between: (i) bupropion or a pharmaceutically acceptable salt thereof; and (ii) one or more excipients that have a negative effect on stability of said bupropion or pharmaceutically acceptable salt thereof; said method comprising: (a) sealing said one or more excipients that have a negative effect on stability of said bupropion or pharmaceutically acceptable salt thereof with a protective coating consisting of hydroxypropylcellulose, hydroxypropyl methylcellulose and mixtures thereof to prevent the absorption of moisture by said one or more excipients that have a negative effect on stability of said bupropion or pharmaceutically acceptable salt thereof to form a sealed excipient component; (b) drying said sealed excipient component until the loss on drying (LOD) is less than 1%; and (c) dry blending said sealed excipient component with bupropion or a pharmaceutically acceptable salt thereof to form a stable solid preparation without an additional stabilizer; wherein said stable solid preparation retains at least 85% w/w of undegraded bupropion or pharmaceutically acceptable salt thereof after storage for 3 months at about 40° C. and about 75% relative humidity.