A method of providing a patient with controlled release of a phenolic opioid using a prodrug capable, upon enzymatic activation, of releasing the phenolic opioid through intra-molecular cyclization leading to formation of a cyclic urea, carbamate or thiocarbamate. See also Fig. 1. WO 2007/140272 PCT/US2007/069683 Figure 1. -o- N-MTX 20 mg/kg -r N-MTX from ex. 19 at 20 mg/kg 0.0 2.5 5.0 7.5 10.0 Time hr Figure 2. -, N-MTX from ex. # 19 at 20 mg/kg --- HMfrom ex. #3 at 20 mg/kg 0.0 2.5 5.0 7.5 10.0 Time hr
