Synthesis of an Esterase-Sensitive Cyclic Prodrug of a Model Hexapeptide Having Enhanced Membrane Permeability and Enzymatic Stability Using a 3-(2′-Hydroxy-4′,6′-Dimethylphenyl)-3,3-Dimethyl Propionic Acid Promoiety

  • Binghe Wang
  • Sanjeev Gangwar
  • Giovanni Pauletti
  • Teruna Siahaan
  • Ronald T. Borchardt
Part of the Methods in Molecular Medicine™ book series (MIMM, volume 23)


One of the major obstacles to the development of biologically active peptides as clinically useful therapeutic agents has been their low permeation through biological barriers (e.g., intestinal mucosa, blood-brain barrier) and their metabolic lability (1,2). Overcoming these problems is a very contemporary issue for the development of peptide pharmaceuticals. In the preceding chapter, we have indicated that masking the C- and N-terminal polar functional groups of a peptide through cyclization with an acyloxyalkoxy linker can greatly enhance the membrane permeation and metabolic stability of the linear peptide (3). In this chapter, we wish to report a method for the preparation of esterase-sensitive cyclic prodrugs of peptides by taking advantage of a unique “trimethyl lock”-facilitated lactonization system (Fig. 1). Substituted phenol propionic acid derivatives such as 2, upon unmasking of the hydroxyl group, undergo a facile spontaneous intramolecular cyclization to release the moieties attached to the carboxyl functional group (Fig. 1) (4, 5, 6). The facile cyclization reaction is the result of the “trimethyl lock”, which was shown earlier to increase the rate of the cyclization reaction in the order of 105–7 (4, 5, 6, 7). The result of such facilitation is that compound 2 has a half-life of only approximately 100 s at room temperature in aqueous solution (8,9). Such systems have been used to develop prodrugs of amines and alcohols (8, 9, 10) and redox-sensitive protecting groups of amines (11).
Fig. 1.

The design of an esterase sensitive prodrug system for the cyclic deriva-tization of peptides.


High Performance Liquid Chromatography Cyclic Peptide Linear Peptide Solid Phase Peptide Synthesis Sodium Hydrogen Carbonate 
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  1. 1.
    Oliyai, R. and Stella, V. J. (1993) Prodrugs of peptides and proteins for improved formulation and delivery. Annu. Rev. Pharmacol. Toxicol. 32, 521–544.CrossRefGoogle Scholar
  2. 2.
    Taylor, M. D. and Amidon, G. L. (ed.) (1994) Peptide-Based Drug Design: Controlling Transport and Metabolism. American Chemical Society, Washington, D. C.Google Scholar
  3. 3.
    Gangwar, S., Pauletti, G. M., Siahaan, T. J., Stella, V. J., and Borchardt, R. T. (1999) Synthesis of an esterase-sensitive cyclic prodrug of a model hexapeptide having enhanced membrane permeability and enzymatic stability using an acyloxyalkoxy promoiety. Meth. Mol. Biol. Vol. 23, Peptidomimetics Protcols (Kazmierski, W. M., ed.), Humana Press, Totowa, NJ, pp. 37–51.Google Scholar
  4. 4.
    Borchardt, R. T. and Cohen, L. A. (1972) Stereopopulation control. III. Facilitation of intramolecular conjugate addition of the carboxyl group. J. Am. Chem. Soc. 94, 9175–9182.CrossRefGoogle Scholar
  5. 5.
    King, M. M. and Cohen, L. A. (1983) Stereopopulation control. 7. Rate enhancement in the lactonization of 3-(o-hydroxyphenyl)propionic acids: dependence on the size of aromatic ring substituents. J. Am. Chem. Soc. 105, 2752–2760.CrossRefGoogle Scholar
  6. 6.
    Milstein, S. and Cohen, L. A. (1972) Stereopopulation control. I. Rate enhancement in the lactonization of o-hydroxyhydrocinnamic acids. J. Am. Chem. Soc. 94, 9158–9165.CrossRefGoogle Scholar
  7. 7.
    Wang, B., Nicolaou, M. G., Liu, S., and Borchardt, R. T. (1996) Structural analysis of a facile lactonization system facilitated by a “trimethyl lock” Bioorg. Chem. 24, 39–49.CrossRefGoogle Scholar
  8. 8.
    Amsberry, K. L. and Borchardt, R. T. (1990) The lactonization of 2′-hydroxy-hydrocinnamic acid amides: potential prodrugs for amines. J. Org. Chem. 55, 5867–5877.CrossRefGoogle Scholar
  9. 9.
    Amsberry, K. L., Gerstenberger, A. L., and Borchardt, R. T. (1991) Amine prodrugs which utilize hydroxy amide lactonization. II. A potential esterase-sensitive amide prodrug. Pharm. Res. 8, 455–461.CrossRefGoogle Scholar
  10. 10.
    Ueda, Y., Mikkilineni, A. B., Knip, J. O., Rose, W. C, Casazza, A. M., and Vyas, D. M. (1993) Novel water soluble phosphate prodrugs of taxol possessing in vivo antitumor activity. Bioorg. Med. Chem. Lett. 3, 1761–1766.CrossRefGoogle Scholar
  11. 11.
    Wang, B., Liu, S., and Borchardt, R. T. (1995) Development of a novel redox-sensitive protecting group for amines which utilizes a facilitated lactonization reaction. J. Org. Chem. 60, 539–543.CrossRefGoogle Scholar
  12. 12.
    Raeissi, S. and Audus, K. L. (1989) Permeability of delta sleep-inducing peptide through monolayers of bovine brain microvessel endothelial cells. J. Pharm. Pharmacol. 41, 848–852.Google Scholar
  13. 13.
    Gray, R., Vander Velde, D., Burke, C. J., Manning, M., Middaugh, C. R., and Borchardt, R. T. (1994) Delta sleep-inducing peptide: solution conformational studies of a membrane-permeable peptide. Biochemistry 37, 293–304.Google Scholar
  14. 14.
    Wang, S. S. (1973) p-Alkoxybenzyl alcohol resin and p-alkoxybenzyloxy-carbonylhydrazide resin for solid phase synthesis of protected peptide fragments. J. Am. Chem. Soc. 95, 1328–1333.Google Scholar
  15. 15.
    Atherton, E. and Sheppard, R. C. (1989) Solid Phase Peptide Synthesis: A Practical Approach. IRL, New York.Google Scholar
  16. 16.
    Stewart, J. M. and Young, J. D. (1984) Solid Phase Peptide Synthesis. Pierce Chemical, Rockford, IL.Google Scholar
  17. 17.
    Bodanszky, M. and Bodanszky, A. (1984) The Practice of Peptide Synthesis. Springer Verlag, New York.Google Scholar
  18. 18.
    Greene, T. W. and Wuts, P. G. M. (1991) Protective Groups in Organic Synthesis. John-Wiley, New York, pp. 240–241.Google Scholar
  19. 19.
    Tung, R. D. and Rich, D. H. (1985) Bis(2-oxo-3-oxazolidinyl) phosphinic chloride (1) as a coupling reagent for N-alkyl amino acids. J. Am. Chem. Soc. 107, 4342–4343.CrossRefGoogle Scholar
  20. 20.
    Pauletti, G. M., Gangwar, S., Wang, B., Siahaan, T. J., and Borchardt, R. T. (1996) Esterase-sensitive cyclic prodrugs of peptides: evaluation of a phenylpropionic acid promoiety in a model hexapeptide. Pharm. Res. 14, 11–17.CrossRefGoogle Scholar
  21. 21.
    Wilson, G., Hassan, I. F., Dix, C. J., Williamson, I., Shah, R., and Mackay, M. (1990) Transport and permeability properties of human Caco-2 cells: an in vitro model of the intestinal epithelial cell barrier. J. Control. Release 11, 25–40.CrossRefGoogle Scholar
  22. 22.
    Pinto, M., Robine-Leon, S., Appay, M.-D., Kedinger, M., Tradou, N., Dussaulx, E., Lacroix, B., Simon-Assmann, P., Haffen, K., Fogh, J., and Zweibaum, A. (1983) Enterocyte-like differentiation and polarization of the human colon carcinoma cell line Caco-2 in culture. Biol. Cell 47, 323–330.Google Scholar
  23. 23.
    Arthursson, P. (1990) Epithelial transport of drugs in cell culture. I: A model for studying the passive diffusion of drugs over intestinal absorptive (Caco-2) cells. J. Pharm. Sci. 79, 476–482.CrossRefGoogle Scholar
  24. 24.
    Pauletti, G. M., Gangwar, S., Okumu, F. W., Siahaan, T. J., Stella, V. J., and Borchardt, R. T. (1996) Esterase-sensitive cyclic prodrugs of peptides: evaluation of an acyloxyalkoxy promoiety in a model hexapeptide. Pharm. Res. 13, 1613–1621.CrossRefGoogle Scholar

Copyright information

© Humana Press Inc., Totowa, NJ 1999

Authors and Affiliations

  • Binghe Wang
    • 1
  • Sanjeev Gangwar
    • 1
  • Giovanni Pauletti
    • 1
  • Teruna Siahaan
    • 1
  • Ronald T. Borchardt
    • 1
  1. 1.Department of Pharmaceutical ChemistryThe University of KansasLawrence

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