Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Mephobarbital”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1997

GC/MS confirmation of barbiturates in blood and urine.

A gas chromatography-mass spectrometric method is described for the quantitative measurement of 6 commonly used barbiturates in blood and urine specimens. The targeted barbiturates are butalbital, amobarbital, pentobarbital, secobarbital, mephobarbital and phenobarbital. They are recovered along with the internal standard, tolybarb, from blood and urine using liquid extraction then alkalated to form the N-ethyl derivatives. The ethylated barbiturates have symmetrical peaks which are well separated from each other on a non-polar methylsilicone capillary column. The derivatives on a non-polar methylsilicone capillary column. The derivatives facilitate quantitations between 50 and 10,000 ng/mL. The day-to-day CVs for all 6 barbiturates were between 4 and 9% at 200 and 5000 ng/mL. The method has been extended for identifying other acidic drugs and drug metabolites. They are mainly non-steroidal anti-inflammatory drugs, diuretics, and anticonvulsants. An additional 83 compounds can be qualitatively identified.

Analgesics↗
PubMedDate not supplied

Chiral separations of enantiomeric pharmaceuticals by capillary electrophoresis using sulphobutyl ether beta-cyclodextrin as isomer selector.

Capillary electrophoresis has developed into an extremely useful technique for the separation of optical isomers. High efficiencies and the availability of many types of isomer selectors allowing rapid and inexpensive methods development make capillary electrophoresis (CE) an attractive alternative to gas chromatography (GC) and high-pressure liquid chromatography (HPLC) for the determination of chiral purity. In this research the separation of the enantiomers of some chiral pharmaceuticals was investigated using anionic sulphobutyl ether-beta-cyclodextrins as isomer selectors. These chiral selectors have a large countercurrent mobility, making them inherently advantageous as selectors as compared to neutral cyclodextrins. The effects of pH, buffer composition and selector concentration on the chiral separation of these compounds was investigated. All of the compounds studied were successfully resolved by the sulphobutyl ether beta-cyclodextrins (SBE-beta-CDs) typically with run times of less than 20 min using low concentrations of the SBE selector (1-5 mM).

Atenolol↗
PubMed1985

Ependymoblastoma associated with prenatal exposure to diphenylhydantoin and methylphenobarbitone.

Ependymoblastoma developed in a 28-month-old girl whose epileptic mother took diphenylhydantoin and methylphenobarbitone throughout pregnancy. The child was also shown to be a genetic carrier for ornithine transcarbamylase deficiency, an x-linked inborn error of urea cycle metabolism. The possibility of transplacental carcinogenesis should be considered, as other juvenile embryonic tumors such as neuroblastoma, melanotic neuroectodermal tumor, and mesenchymoma have been reported in offspring after diphenylhydantoin use by the mother during pregnancy.

Brain Neoplasms↗
PubMed1994

Molecular modelling of the inclusion complexes between beta-cyclodextrin and (R)/(S)-methylphenobarbitone and its application to HPLC.

Molecular modelling of beta-cyclodextrin and optimisation of its potential energy suggests that a favoured conformation is that distorted from a symmetrical torus. The inclusion of water molecules into the torus cavity simulates the increased stability in an aqueous solvent. Complexes of beta-cyclodextrin with (R)- and (S)-enantiomers of methylphenobarbitone have been modelled and energetically optimised by the application of molecular mechanics. The simulations suggests that the guest molecules adopt an orientation in which the phenyl ring is projected into the torus cavity, with in each case the plane of the ring parallel to a longer axis of the distorted torus and slightly displaced from the axis through the torus cavity. It is suggested that the asymmetry in the macrocyclic ring contributes to chiral recognition as a result of additional discriminatory binding to the barbiturate ring residue of each enantiomer, which occupy different 3D geometries. The enantiomers form complexes of different minimum potential energies. The resulting difference in complex stability can be related to the behaviour of beta-cyclodextrin, as a mobile phase additive in reverse-phase HPLC to effect chiral separation of rac-methylphenobarbitone during chromatography.

Chromatography, High Pressure Liquid↗
PubMed2003

Monolithic silica columns with chemically bonded beta-cyclodextrin as a stationary phase for enantiomer separations of chiral pharmaceuticals.

An enantioselective silica rod type chiral stationary phase (CSP) is presented; a novel combination of the well known enantiomer separation properties of beta-cyclodextrin and the unique properties concerning the flow behavior of silica monoliths. Two different synthesis routes are described, and it was found that the in situ modification of a plain silica rod column turned out to be the best. The chromatographic behaviour of the beta-cyclodextrin silica rod was studied and compared with a very similar commercially available beta-cyclodextrin bonded particulate material (ChiraDex). Even if the amount of beta-cyclodextrin bound to the silica rod was only about half of the amount of beta-cyclodextrin bound to ChiraDex) particles, good resolutions were achieved for a set of chiral test components like Chromakalin, Prominal, Oxazepam, Methadone and some other drugs. By taking advantage of the unique features of the silica rods relating to their flat H/u (Van Deemter) curves, fast enantiomer separations could be demonstrated.

Chromatography↗