Controlled release of morphine from a poloxamer 407 gel

• Measurement of in vitro release characteristics of morphine from a P407 based gel.
• Measurement was done with a dissolution cell.
• The morphine release from the P407 based gel followed zero-order kinetics.
• The constant release from the P407 based gel was 150 μg cm−2 h−1.

Treatment of painful ulcers is discouraging. Topical morphine has been described as a useful therapeutic adjunct in some patients. In the development of a new analgesic product, we studied the in vitro release characteristics of a new topical formulation containing 0.5% (w/w) morphine–HCl in a poloxamer 407 (P407) based gel.A diffusion cell was used for measurement of in vitro release characteristics. The donor compartment (DC) and the receptor compartment (RC) were separated by a 5000 Da cellulose acetate membrane.The morphine–HCl release from this developed P407 based gel followed zero-order kinetics with a constant release of 150 μg cm−2 h−1. Our results support the use of this P407 gel as a sustained release topical formulation in the pharmacological treatment of painful ulcers. Future research welcomes a formulation with release characteristics leading to less frequent application.

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