Cancer Chemotherapy and Pharmacology

, Volume 20, Issue 4, pp 316–318

Serum tamoxifen concentrations in the athymic nude mouse after three methods of administration

  • Michael W. DeGregorio
  • Bruce J. Wilbur
  • Ester Coronado
  • C. Kent Osborne
Original Articles Tamoxifen, Breast Cancer

DOI: 10.1007/BF00262583

Cite this article as:
DeGregorio, M.W., Wilbur, B.J., Coronado, E. et al. Cancer Chemother. Pharmacol. (1987) 20: 316. doi:10.1007/BF00262583

Summary

The athymic nude mouse has been used as an in vivo model for pharmacologic studies of the antiestrogen, tamoxifen. We hav examined the steady-state serum tamoxifen concentrations achieved in mice with s. c. slow-release pellets, s. c. injections, and i. p. injections, in an attempt to identify a method that would yield serum levels similar to those observed in patients receiving tamoxifen therapy. Tamoxifen and tamoxifen metabolites were examined by a high-performance liquid chromatography assay which has a sensitivity of 8 ng/ml. Tamoxifen metabolites were not observed with any dose or schedule. After slow-release pellets containing 5 or 25 mg tamoxifen no tamoxifen was detectable, even after 2 weeks of treatment. Very low levels (0.07 μM) were found with 50-mg pellets. Tamoxifen was also not detected either with daily s. c. injections of 500 μg/mouse or with i. p. injections of 2.5 mg/kg. However, daily s. c. injections of 1000 μg or i. p. injections of 25, 50, o4 100 mg/kg resulted in tamoxifen concentrations ranging from 0.21 to 0.51 μM which are similar to those observed in patients. Thus, clinically relevant tamoxifen concentrations can be achieved in the nude mouse with either of these methods of administration.

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Michael W. DeGregorio
    • 1
    • 2
  • Bruce J. Wilbur
    • 2
  • Ester Coronado
    • 3
  • C. Kent Osborne
    • 3
  1. 1.Cancer Pharmacokinetics LaboratoryChildren's Cancer Research InstituteSan FranciscoUSA
  2. 2.Cancer Research Institute1282-M University of CaliforniaSan FranciscoUSA
  3. 3.Department of Medicine/OncologyUniversity of Texas Health Science Center at San AntonioSan AntonioUSA

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