Abstract
Kahalalide F is a novel marine-derived antitumor agent isolated from the marine mollusk Elysia rufescens, an organism living in the seas near Hawaii. The compound has shown highly selective in vitro activity against prostate tumors and phase I trials in patients with androgen independent prostate tumors incorporating a daily times five and weekly schedule have been initiated. Kahalalide F is pharmaceutically formulated as a lyophilized product containing 150 microg active substance per dosage unit. Prior to i.v. administration it is reconstituted with a solution composed of Cremophor EL, ethanol absolute and Water for Injection (CEW, 5/5/90% v/v/v) with further dilution in 0.9% w/v sodium chloride for infusion. The aim of this study was to investigate the compatibility and stability of kahalalide F with different infusion systems prior to the start of clinical trials with the compound. Due to the presence of Cremophor EL in the infusion solution, leaching of diethylhexyl phthalate (DEHP) from polyvinyl chloride infusion containers (PVC, Add-a-Flex) was found. Loss of kahalalide F as a consequence of sorption to contact surfaces was shown with an infusion container composed of low density polyethylene (LD-PE, Miniflac). We conclude that kahalalide F must be administered in a 3-h infusion in concentrations of 0.5 microg/mL to 14.7 microg/mL using an administration set consisting of a glass container and a low-extrables, DEHP-free extension set. Kahalalide F 150 microg/vial powder for infusion reconstituted with 5/5/90% v/v/v CEW is stable in the original container for at least 24 h at room temperature (+20-25 degrees C) and ambient light conditions. Infusion solutions stored in glass infusion containers at either room temperature (+20-25 degrees C, in the dark) or refrigerated conditions (+2-8 degrees C, in the dark) are stable for at least 5 days after preparation.