51018-29-2Relevant articles and documents
New resolving bases for ibuprofen and mandelic acid: Qualification by binary phase diagrams
Ebbers, Eelco J.,Plum, Bart J. M.,Ariaans, Gerry J. A.,Kaptein, Bernard,Broxterman, Quirinus B.,Bruggink, Alle,Zwanenburg, Binne
, p. 4047 - 4057 (1997)
New resolving bases for ibuprofen 1 and mandelic acid 2 were studied and qualified by their binary phase diagrams of the corresponding salts. It was shown that analysis of the binary phase diagrams gives a good prediction for a resolution process. A comparison of resolving bases revealed that (S)-phenylglycinol (S)-7 is the best resolving base for ibuprofen 1. By the same procedure, various resolving bases for mandelic acid 2 were studied. The known resolving base (S)-MBA 9 was found to be the best for this acid.
Prodrugs as drug delivery systems. XXV: Hydrolysis of oxazolidines - A potential new prodrug type
Johansen,Bundgaard
, p. 1294 - 1298 (2007/10/02)
The hydrolysis kinetics of several oxazolidines derived from (-)-ephedrine and various aldehydes and ketones were studied to assess their suitability as prodrug forms for β-amino alcohols and/or carbonyl-containing compounds. The oxazolidines were found to undergo a facile and complete hydrolysis in the pH range of 1-11 at 37°. The hydrolysis rates were subject to general acid-base catalysis by buffer substances and depended strongly on pH. Most oxazolidines showed sigmoidal pH-rate profiles with maximum rates at pH > 7-7.5. At pH 7.40 and 37° the following half-lives of hydrolysis for the various ephedrine oxazolidines were found: 5 sec (formaldehyde), 18 sec (propionaldehyde), 5 min (benzaldehyde), 5 sec (salicylaldehyde), 30 min (pivalaldehyde), 4 min (acetone), and 6 min (cyclohexanone). The reaction rates in neutral and basic solutions were shown to decrease with increasing steric effects of the substituents derived from the carbonyl component and to decrease with increasing basicity of the oxazolidines. The oxazolidines are weaker bases (pK(a) 5.2-6.9) than the parent β-amino alcohol and more lipophilic at physiological pH. It is suggested that oxazolidines can be considered as potentially useful prodrug candidates for drugs containing a β-amino alcohol moiety or carbonyl groups.