The pharmacokinetics of subcutaneous bolus cytosine arabinoside in an arachis oil plus aluminium distearate suspension.

An attempt was made to create a delayed release preparation of cytosine arabinoside (araC) which could be administered subcutaneously, and would produce plasma levels similar to steady state infusion concentrations. A thixotropic suspension of araC in arachis oil and aluminium distearate was formulated. This preparation was similar to that previously used with bleomycin oil suspension and procaine penicillin. Two hundred mg/ml of araC in arachis oil containing varying amounts of aluminium distearate were administered firstly to New Zealand White rabbits and then to patients with acute myelogenous leukaemia. This preparation was well tolerated by both rabbits and patients but did not delay the release of araC from the subcutaneous tissues.