Comparison in purity and antitumor effect of brand and generic paclitaxel against human ovarian cancer cells by an in vitro experimental model.

CONTEXT

The purity and the therapeutic effectiveness of the generic paclitaxel have not yet been examined and compared to the original brand form.

OBJECTIVE

This study aimed to compare the in vitro purity and biological effects of original brand form (Taxol) and a generic drug of paclitaxel.

MATERIALS AND METHODS

Purity was determined by high-performance liquid chromatography analysis, cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay, cell proliferation by clonogenic assay, morphology by Liu's staining, and cell cycle distribution by DNA histogram.

RESULTS

Taxol and generic paclitaxel shared similar high-performance liquid chromatography profiles with a major peak at the same retention time and ultraviolet spectrum. Generic paclitaxel inhibited the cell viability to an extent greater than Taxol. By assessing the IC(50), generic paclitaxel also exhibited a greater inhibitory activity on clonogenicity of human ovarian adenocarcinoma SKOV-3 cells. Although both generic paclitaxel and Taxol arrested SKOV-3 and ES-2 cells at G2/M phase with concurrent development of hypoploid and polyploid cells, Taxol treatment exhibited markedly less extent of these changes. Observation of cellular morphology revealed a greater amount of mitotic catastrophe-like and apoptotic cells in generic paclitaxel-treated cells than Taxol-treated cells.

DISCUSSION AND CONCLUSION

The results suggest that generic paclitaxel may possess a greater cell death inducing capacity and clonogenicity inhibitory activity against ovarian cancer cells than the original brand Taxol of the same purity. We conclude that this experimental model for assessing the difference between generic and brand name drugs might be considered as a reference while determining their interchangeability and could be easily established in a hospital-based laboratory.