RESUMO
The aim of the present study was to perform in vitro and in vivo assessments of the antineoplastic action of 4-amino-pyrimidine encapsulated in liposomes. Liposomes were prepared and characterized for particle size and drug encapsulation and submitted to long-term stability tests. Cytotoxicity assays were performed in HeLa cells. Antineoplastic activity was investigated using the experimental sarcoma 180 tumor in Swiss albino mice. Encapsulation efficiency was 82.93 ± 0.04% and no significant changes were found with respect to particle size or pH after centrifugation and mechanical agitation tests. The in vitro results at concentration of 20 µg/mL indicated a considerable reduction in cell viability after treatment with encapsulated pyrimidine (75.91%). The in vivo assays using the compounds in encapsulated and free forms and 5-fluorouracil achieved tumor inhibition rates of 66.47 ± 26.8%, 50.46 ± 16.24% and 14.47 ± 9.22%, respectively. Mitotic counts demonstrated a greater reduction in the number of mitoses in animals treated with liposomal pyrimidine (32.15%) compared to those treated with the pyrimidine free (87.69%) and 5-fluorouracil (71.39%). This study demonstrated that the development of liposome formulations containing 4-amino-pyrimidine is a promising alternative for overcoming limitations related to the toxicity of current cancer treatment, ensuring greater therapeutic efficacy.
