Altomare C, Trapani G, Latrofa A, Serra M, Sanna E, Biggio G, Liso G. Highly water-soluble derivatives of the anesthetic agent propofol: in vitro and in vivo evaluation of cyclic amino acid esters.
Eur J Pharm Sci 2004;
20:17-26. [PMID:
13678789 DOI:
10.1016/s0928-0987(03)00161-1]
[Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cyclic amino acid esters of propofol were synthesized in an attempt to develop new water-soluble anesthetic agents. Their solubility and stability in aqueous solution, and their ability to release propofol in vitro under physiological conditions were determined. L-Proline (6a) and racemic nipecotic acid (6c) esters were found to be highly soluble in water. Sufficiently stable at physiological pH (half-lives >6 h), the alpha-amino acid esters, 6a and 6b, were found to be quantitatively hydrolyzed in plasma and liver esterase solutions within a few minutes, showing prodrug behavior. The in vitro activity of the esters, determined either by the [(35)S]tert-butylbicyclophosphorothionate ([(35)S]TBPS) binding assay or electrophysiological measurements of the action at cloned human receptors, proved to be a mechanism involving allosteric modulation of GABA(A) receptors. Indeed, L-proline (6a), and racemic pipecolinate (6b) and nipecotate (6c), like propofol, reduced [(35)S]TBPS binding, whereas isonipecotate (6d) showed bicuculline-like behavior, increasing [(35)S]TBPS binding. A nonlinear relation between GABA(A) receptor binding affinity and lipophilicity, as assessed by reversed-phase high-performance liquid chromatography, emerged as a trend. The in vivo anticonvulsant and anesthetic activities of prolinate 6a, intraperitoneally administered in water solution, showed that is a water-soluble propofol prodrug candidate for developing formulations useful for parenteral administration.
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