RESUMO
The usefulness of thin-layer chromatography (TLC) as an efficient measuring technique in the studies of oscillatory trans-enantiomerization of profens from the S to the R configuration (and vice versa) during their storage as 70% ethanol solutions is demonstrated in the literature. S-(+)-ibuprofen, S-(+)-naproxen, and S,R-(+/-)-2-phenylpropionic acid are utilized as the test profens. It is proven possible to show oscillatory instability with the racemic S,R-(+/-)-2-phenylpropionic acid also. Correctness of the TLC assessment is successfully confirmed by means of polarimetry. Upon these preliminary results, it is concluded that the most probable mechanism might embrace the keto-enol tautomerism because of a convenient migration of the proton from one moiety of the profen molecule to another in an aqueous medium. To indirectly verify this hypothesis, profens are stored in dichloromethane, deliberately hampering their ability to dissociate and to re-structure. It is obvious though that the (much less pronounced) electrolytic dissociation can occur in the non-aqueous media as well. It is shown that the non-aqueous solvent considerably suppresses, although they do not completely eradicate, the oscillatory trans-enantiomerization of profens. In view of these findings, the reports which claim a predominant therapeutic potential of the respective S-profens become less convincing and certainly need reconsideration.
Assuntos
Cromatografia em Camada Fina/métodos , Ibuprofeno/química , Cloreto de Metileno/química , Naproxeno/química , Fenilpropionatos/química , EstereoisomerismoRESUMO
The authors analysed 13 cases of West's syndrome (8 females and 5 males observed in a period of 30 months. In only one case there was history of perinatal trauma. In 7 children the psychomotor development was very good until the time of development of seizures, in 2 children hyperexcitability was present, 1 was obese, 2 had various infections. In 7 cases the seizures developed within 1 to 20 days after DiPerTe or poliomyelitis vaccination. The time from the onset of seizures to beginning of hormonal treatment ranged from 4 weeks to 5 months. Corticosteroids or ACTH were administered for 2 months at least, and benzodiazepine drugs and/or phenobarbital were given additionally. It was found that the effects of treatment were much better in children referred for treatment early after onset of seizures. In cases with delayed hormonal treatment mental retardation was considerable and seizures were frequent.
