Time and dose dependent study of doxorubicin induced DU-145 cytotoxicity

Doxorubicin is one of the most effective anti-tumour agent. To clarify whether a single dose produces its effects soon after dosing or only after hours or days and whether the effects are brief or prolonged, time-dose relationships were explored by calculating lethal time (LT(50)) values which is a statistical estimate of the time from dosage to death of 50% of the organisms/ or cells in a very large population subjected to a toxicant under specific conditions. This was achieved by the log-time log-dose curve which may be used to predict the proper doses to be used in long-term studies. Drug chemosensitivity using DU-145 cell lines have been investigated for this purpose. The results shows that the effects of doxorubicin started only after 24 hrs; however, resistance was developed, 40 hrs was the time required to kill 50% of cells , and post-incubation with fresh media (F.M.) exhibited more cell damages. It is concluded that doxorubicin is effective only after 24 hrs with resistance developed and post-incubation with F.M after treating cells with doxorubicin causes more damage than continuous incubation with the drug.