A new micronized formulation of 2-methoxyestradiol-bis-sulfamate (STX140) is therapeutically potent against breast cancer

Anticancer Res. 2008 Mar-Apr;28(2A):577-81.


There is a continued need for orally bioavailable anticancer compounds that exhibit good efficacy against breast cancer. STX140, a derivative of 2-methoxyestradiol (2-MeOE2), has been shown to have excellent oral bioavailability and significantly reduces tumor growth. A new micronized formulation of STX140 has now been developed and its pharmacokinetics (PK) in rats and effect on MDA-MB-231 breast cancer growth in nude mice was investigated.

Materials and methods: For the PK studies, female Wistar rats were treated orally with STX140 in two separate vehicles (10% tetrahydrofuran (THF) in propylene glycol (PG) or 0.5% methyl cellulose (MC) in saline) and plasma samples taken for high performance liquid chromatography analysis over 48 h. For the tumor efficacy studies, female nude mice were inoculated with MDA-MB-231 breast cancer cells and then treated orally with a range of doses of STX140.

Results: The PK studies demonstrated that the THF/PG vehicle resulted in a greater oral bioavailability of STX140 compared to the 0.5% MC vehicle. However, this was not translated to the tumor efficacy studies where STX140 at 20 mg/kg in either vehicle caused a significant reduction in tumor volume.

Conclusion: The new micronized formulation of STX140 is orally bioavailable and efficacious at inhibiting MDA-MB-231 breast tumor growth.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Cell Line, Tumor
  • Dosage Forms
  • Estrenes / administration & dosage
  • Estrenes / pharmacokinetics*
  • Estrenes / therapeutic use*
  • Female
  • Male
  • Mammary Neoplasms, Experimental / drug therapy*
  • Mammary Neoplasms, Experimental / metabolism
  • Mice
  • Mice, Nude
  • Rats
  • Rats, Sprague-Dawley
  • Viscosity
  • Xenograft Model Antitumor Assays


  • 2-methoxyestradiol-3,17-O,O-bis(sulfamate)
  • Dosage Forms
  • Estrenes