title: A comparison of prodrug esters of nipecotic acid.
abstract: The relative ability of the enantiomers of the ethyl and m-nitrophenyl esters of nipecotic acid to block convulsions induced by bicuculline and pentylenetetrazol, as well as to block the uptake of GABA into whole brain mini-slices, was studied in mice. Neither (+)ethyl nipecotate hydrogen tartrate [(+)E.Tartrate], which is hydrolyzed to (-)nipecotic acid, nor (-)ethyl nipecotate hydrogen tartrate [(-)E.Tartrate], which is hydrolyzed to (+)nipecotic acid, provided protection against challenge with bicuculline. Both (+)E.Tartrate and (-)ethyl nipecotate hydrochloride [(-)E.HCl], which are hydrolyzed to (-)nipecotic acid, blocked seizures induced by pentylenetetrazol. However, neither (-)E.Tartrate nor (+)ethyl nipecotate hydrochloride [(+)E.HCl], which are hydrolyzed to (+)nipecotic acid, provided significant protection against challenge with pentylenetetrazol. These results agree with the relative ability of these compounds to inhibit the uptake of GABA, where (-)nipecotic acid was more potent than (+)nipecotic acid and (+)E.Tartrate was more potent than (-)E.Tartrate. The enantiomers of m-nitrophenyl-3-piperidinecarboxylate hydrochloride, (+)MNPC.HCl and (-)MNPC.HCl, were almost equi-effective in preventing seizures induced by bicuculline. This lack of significant difference in anticonvulsant activity is in contrast with the ability to inhibit the uptake of GABA, where (-)MNPC.HCl was significantly more potent than (+)MNPC.HCl. Changing the route of administration from subcutaneous to intraperitoneal injection reduced the onset of time of the peak effect and the anticonvulsant potency of (+/-)MNPC.HCl. Cholinergic effects were observed with the administration of (+)E.Tartrate and (-)E.HCl, but not with (-)E.Tartrate, (+)E.HCl, (+)MNPC.HCl or (-)MNPC.HCl.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: College of Pharmacy, University of Toledo, Ohio 43606.
authors.forename: C N
authors.initials: CN
authors.lastname: Hinko
authors.forename: A M
authors.initials: AM
authors.lastname: Crider
authors.forename: J D
authors.initials: JD
authors.lastname: Wood
mesh_terms: D000818:Animals; D000927:Anticonvulsants; D001640:Bicuculline; D004952:Esters; D018756:GABA Antagonists; D008297:Male; D051379:Mice; D009557:Nipecotic Acids / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D010277:Parasympathomimetics; D010433:Pentylenetetrazole; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011355:Prodrugs / Q000378:metabolism*; D011392:Proline / Q000031:analogs & derivatives*; D012640:Seizures / Q000139:chemically induced / Q000517:prevention & control; D013331:Strychnine
chemical_list: D000927:Anticonvulsants; D004952:Esters; D018756:GABA Antagonists; D009557:Nipecotic Acids; D010277:Parasympathomimetics; D004364:Pharmaceutical Preparations; D011355:Prodrugs; C030278:nipecotic acid; D011392:Proline; C010983:homoproline; D013331:Strychnine; D010433:Pentylenetetrazole; D001640:Bicuculline