Deoxycytidine - chemistry, Camptothecin - chemistry, Prospective Studies, Ganciclovir - chemistry, Drug Compounding - methods, Humans, Antineoplastic Agents - chemistry, Cytarabine - chemistry, Cyclophosphamide - chemistry, Occupational Exposure - analysis, Fluorouracil - chemistry, Ifosfamide - chemistry, Deoxycytidine - analogs & derivatives, Drug Contamin...