| 摘要 |
Implantable osmotic pump devices and systems include multiple osmotic pumps and/or semipermeable membranes to extend the useful life cycle and functionality of the drug delivery system. Use of an implantable system including multiple implantable osmotic pumps allows different drugs to be administered from the same implanted system. One or more of the semipermeable membranes of the system may be initially sealed by an overlying impermeable membrane upon implantation of the system into the patient. When the patient develops a tolerance to a first drug or to a first dose of the first drug, the impermeable membrane may be breached, to expose the underlying semipermeable membrane to the osmotic pressure of the patient at the implant site. This causes the infusion rate to increase, thereby providing the patient with the needed relief and/or other desired therapeutic effect. In the case of a multiple pump system, breaching an impermeable membrane may cause the infusion of a second drug. The second drug may potentiate a therapeutic effect (such as an analgesic effect) of the first drug, as is the case with Sufentanil and Clonidine.
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