Enantiomeric separation of propranolol and selected metabolites by using capillary electrophoresis with hydroxypropyl-beta-cyclodextrin as chiral selector.

A capillary electrophoresis (CE) investigation of the enantiomeric separation of propranolol and some of its metabolites using CE was undertaken. Resolution of the enantiomers was achieved using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as the chiral selector. Parameters found to influence separation include cyclodextrin concentration, potential, pH and organic solvent/additive. It was observed that 17 mM HP-beta-CD gave optimum separation over the concentration range used in this study, however different racemates appear to have best resolution at different CD concentration. The potential does not have a great effect on enantiomer resolution, but appears to cause relative metabolite migration times to alter such that separation is affected. Carrier pH affects both migration time, and enantiomer resolution and metabolite separation. Above pH 5 inferior results are obtained. This is the first report of enantiomeric resolution of propranolol metabolites using CE.

In vitro evidence for direct complexation of ADR-529/ICRF-187 [(+)-1,2-bis-(3,5-dioxo-piperazin-1-yl)propane] onto an existing ferric-anthracycline complex.

ADR-529 protects against anthracycline cardiotoxicity, possibly by preventing free radical induction. We hypothesize that this occurs by ADR-529 forming a ternary anthracycline-iron-ADR-529 complex. This study used 200-MHz Fourier-transformed NMR to demonstrate the ability of ADR-529 to do this. Peak assignments were by proton-correlated spectroscopy and proton-carbon heteronuclear-correlated spectroscopy. Ga3+ served as a probe for Fe3+, and D2O was the system solvent. Doxorubicin and epirubicin were the studied drugs. Proton spectra of multiple combinations (including pure standards as controls) were obtained. Both Ga3+ plus ADR-529 and Ga3+ plus doxorubicin showed evidence of complexation, as seen by appropriate peak shifts and changes in the associated coupling constants. Ga3+ plus ADR-529 plus epirubicin showed complexation different from that of Ga3+ plus ADR-529 or Ga3+ plus doxorubicin and consistent with the proposed structure. We conclude that ADR-529 would be able to form a ternary complex with an existing anthracycline-Fe3+ complex in an isolated aqueous environment.

Enzymic sulfation of bile salts. Partial purification and characterization of an enzyme from the liver of the shark Heterodontus portusjacksoni that catalyses the sulfation of the shark bile steroid 5 beta-scymnol.

An enzyme system which catalyses the transfer of the sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to the bile steroid 5 beta-scymnol has been isolated and characterized from the liver of the shark Heterodontus portusjacksoni (Meyer 1793). The enzyme is present in the cytosol fraction of liver cells. It was partially purified by hydroxylapatite chromatography, molecular sizing by G100-Sephadex and isoelectrofocusing electrophoresis. The apparent Km value for 3'-phosphoadenosine-5'-phosphosulfate was 4 microM and that for 5 beta-scymnol, 14 microM. The enzyme activity is inhibited by iodoacetate and p-chloromercuribenzoate indicating the possible requirement of a sulfhydryl group for activity. The molecular weight of the enzyme was estimated to be 40 kDa by gel filtration. This was verified by running the partially purified material on a native gel and electrophoretically separating two major bands corresponding to molecular weights of 40 and 45 kDa, respectively. Isoelectric focusing of the purified material resulted in two major bands with pI values of 5.0 and 5.85. Enzymatic activity was found to be optimal at a pH of 6.5 with little activity recorded at pH 5.0 and 8.0.