Pharmaceutical Research

, Volume 13, Issue 11, pp 1615–1623 | Cite as

Esterase-Sensitive Cyclic Prodrugs of Peptides: Evaluation of an Acyloxyalkoxy Promoiety in a Model Hexapeptide

  • Giovanni M. Pauletti
  • Sanjeev Gangwar
  • Franklin W. Okumu
  • Teruna J. Siahaan
  • Valentine J. Stella
  • Ronald T. Borchardt


Purpose. To evaluate a cyclic acyloxyalkoxycarbamate prodrug of a model hexapeptide (H-Trp-Ala-Gly-Gly-Asp-Ala-OH) as a novel approach to enhance the membrane permeation of the peptide and stabilize it to metabolism.

Methods. Conversion to the linear hexapeptide was studied at 37°C in aqueous buffered solutions and in various biological milieus having measurable esterase activities. Transport and metabolism characteristics were assessed using the Caco-2 cell culture model.

Results. In buffered solutions the cyclic prodrug degraded chemically to the linear hexapeptide in stoichiometric amounts. Maximum stability was observed between pH 3–4. In 90% human plasma (t1/2 = 100 ± 4 min) and in homogenates of the rat intestinal mucosa (t- = 136 ± 4 min) and rat liver (t- = 65 ± 3 min), the cyclic prodrug disappeared faster than in buffered solution, pH 7.4 (t- = 206 ± 11 min). Pretreatment of these media with paraoxon significantly decreased the degradation rate of the prodrug. When applied to the apical side of Caco-2 cell monolayers, the cyclic prodrug (t- = 282 ± 25 min) was significantly more stable than the hexapeptide (t- = 14 min) and at least 76-fold more able to permeate (Papp = 1.30 ± 0.15 × 10−7 cm/ s) than the parent peptide (Papp ≤ 0.17 × 10−8 cm/s).

Conclusions. Preparation of a cyclic peptide using an acyloxyalkoxy promoiety reduced the lability of the peptide to peptidase metabolism and substantially increased its permeation through biological membranes. In various biological media the parent peptide was released from the prodrug by an apparent esterase-catalyzed reaction, sensitive to paraoxon inhibition.

esterase-sensitive prodrug peptide delivery Caco-2 cells membrane permeability enzymatic stability chemical stability 


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  1. 1.
    V. H. L. Lee and A. Yamamoto. Adv. Drug Delivery Rev. 4:171–207 (1990).Google Scholar
  2. 2.
    V. Bocci. Adv. Drug Delivery Rev. 4:149–169 (1990).Google Scholar
  3. 3.
    X. H. Zhou. J. Controlled Release 29:239–252 (1994).Google Scholar
  4. 4.
    G. M. Pauletti, S. Gangwar, G. T. Knipp, M. M. Nerurkar, F. W. Okumu, K. Tamura, T. J. Siahaan, and R. T. Borchardt. J. Controlled Release 41:3–17 (1996).Google Scholar
  5. 5.
    R. A. Gray, D. G. Vander Velde, C. J. Burke, M. C. Manning, C. R. Middaugh, and R. T. Borchadt. Biochemistry 33:1323–1331 (1994).Google Scholar
  6. 6.
    W. A. Banks, A. J. Kastin, D. H. Coy, and E. Angulo. Brain. Res. Bull. 17:155–158 (1986).Google Scholar
  7. 7.
    H. Bundgaard. Adv. Drug Delivery Rev. 8:1–38 (1992).Google Scholar
  8. 8.
    R. Oliyai and V. J. Stella. Ann. Rev. Pharmacol. Toxicol. 32:521–544 (1993).Google Scholar
  9. 9.
    J. K. McDonald and A. J. Barrett. Mammalian Proteases: A Glossary and Bibliography, Vol. 2, Exopeptidases, Academic Press, New York, 1986.Google Scholar
  10. 10.
    F. W. Okumu, G. M. Pauletti, D. G. Vander Velde, T. J. Siahaan, and R. T. Borchardt. Pharm. Res. 12:S-302 (1995).Google Scholar
  11. 11.
    S. Gangwar, G. M. Pauletti, T. J. Siahaan, V. J. Stella, and R. T. Borchardt. J. Org. Chem. (submitted).Google Scholar
  12. 12.
    M. Inoue, M. Morikawa, M. Tsuboi, and M. Sugiura. Jpn. J. Pharmacol. 29:9–16 (1979).Google Scholar
  13. 13.
    F. M. Williams. Clin. Pharmacokinet. 10:392–403 (1985).Google Scholar
  14. 14.
    I. J. Hidalgo, T. J. Raub, and R. T. Borchardt. Gastroenterology 96:736–749 (1989).Google Scholar
  15. 15.
    P. Artursson. J. Pharm. Sci. 79:476–482 (1990).Google Scholar
  16. 16.
    M. Pinto, S. Robine-Leon, M.-D. Appay, M. Kedinger, N. Tradou, E. Dussaulx, B. Lacroix, P. Simon-Assmann, K. Haffen, J. Fogh, and A. Zweibaum. Biol. Cell 47:323–330 (1983).Google Scholar
  17. 17.
    G. Wilson, I. F. Hassan, C. J. Dix, I. Williamson, R. Shah, and M. Mackay. J. Controlled Release 11:25–40 (1990).Google Scholar
  18. 18.
    H. Liu, S. Ong, L. Glunz, and C. Pidgeon. Anal. Chem. 67:3550–3557 (1995).Google Scholar
  19. 19.
    P. F. Augustijns and R. T. Borchardt. Drug Metab. Dispos. 23:1372–1378 (1995).Google Scholar
  20. 20.
    C. S. Cook, P. J. Karabatsos, G. L. Schoenhard, and A. Karim. Pharm. Res. 12:1158–1164 (1995).Google Scholar
  21. 21.
    W. N. Aldridge. Biochem. J. 53:117–124 (1953).Google Scholar
  22. 22.
    K. Takahashi, S. Tamagawa, H. Sakano, T. Katagi, and N. Mizuno. Biol. Pharm. Bull. 18:1401–1404 (1995).Google Scholar
  23. 23.
    W. N. Aldridge. Biochem. J. 53:110–117 (1953).Google Scholar
  24. 24.
    D. S. Auld and B. Holmquist. Biochemistry 13:4355–4361 (1974).Google Scholar
  25. 25.
    S. Gangwar, S. D. S. Jois, T. J. Siahaan, D. G. Vander Velde, V. J. Stella, and R. T. Borchardt. Pharm. Res. 13:1657–1662 (1996).Google Scholar

Copyright information

© Plenum Publishing Corporation 1996

Authors and Affiliations

  • Giovanni M. Pauletti
    • 1
  • Sanjeev Gangwar
    • 1
  • Franklin W. Okumu
    • 1
  • Teruna J. Siahaan
    • 1
  • Valentine J. Stella
    • 1
  • Ronald T. Borchardt
    • 1
  1. 1.Department of Pharmaceutical ChemistryThe University of KansasLawrence

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