An analgesic composition in parenteral unit dosage form or in a unit dosage form suitable for delivery via the mucosa comprising an amount of buprenorphine which is less than the clinical dose required to achieve pain relief and an amount of naloxone such that the ratio by weight of buprenorphine to naloxone is in the range of from 12. Regions in a cluster file system are defined to support a block allocation. The imaging time is reduced since the actinic reaction rate is increased at the elevated temperature. A mechanism is provided within the passageway for exerting a bias force against the pressure responsive element which is sufficient to close the inlet opening to fluid flow absent a pre-established level of fluid pressure exerted on the pressure responsive element.