The present invention relates to process for the preparation of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy-camptothecin hydrochloride trihydrate and process for the isolation of 1-chlorocarbonyl-4-piperidinopiperidine and novel crystalline form of 1-chlorocarbonyl-4-piperidinopiperidine and 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy-camptothecin.