¹M. M. College of Pharmacy, M. M. Deemed to be University, Mullana 133207, Haryana India DOI : 10.29228/jrp.263 The clinical use of irinotecan (IRI), one of the most commonly used antitumor drugs for colon cancer, is limited by its numerous side effects, and it also lacks selectivity and specificity for tumor cells. When conjugated with fullerenes and biotin, this drug may serve as a drug of choice to reduce these side effects. Fullerenes are an allotropic form of carbon with a closed cage-like structure that can act as a drug carrier, and the presence of biotin makes it a promising targeting agent. In this work, we performed release as well as toxicity comparison studies between pure irinotecan and fullerene-biotin-conjugated irinotecan. The release studies were performed by HPLC (High Performance Liquid Chromatography), while the toxicity studies were performed on a model of colon tumors in gopher rats. All animals were divided into four groups, namely normal, control, test and standard groups. Biochemical parameters and histopathological studies were performed to compare the acute toxicity of irinotecan and the conjugate (C60-PEI-biotin/IRI). It was found that IRI alone was unable to reduce the toxicity caused by DMH (1,2-dimethylhydrazine), whereas its conjugate was able to significantly reduce the toxic effects, which was also evident in the histopathological studies. Therefore, the study suggests that the administration of conjugated IRI reduces toxicity and proves to be a potential candidate for a preventive chemo effect. Keywords : Antitumor; irinotecan; toxicity; fullerene; conjugate