Capillary electrophoresis separation of aminoalkanol derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.0(2,6)]dec-8-ene-3,5,10-trione as potential anticancer drugs.

The purpose of this study, the direct separation of aminoalkanol derivatives I and II of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.0(2,6) ]dec-8-ene-3,5,10-trione, which was found in earlier studies as potential anticancer drugs, were performed. Capillary electrophoresis offers the possibility of fast, cheap, and reproducible separations for compounds I and II. In this paper, the simultaneous separation of I and II by capillary zone electrophoresis has been achieved within 8 min by use of 50 mM phosphate buffer of pH 2.5. Analysis of the two compounds in the serum plasma standards was conducted. Limits of detection of I and II by UV absorbance at 200 nm were achieved in the range of 156.3-156.6 ng/mL. The method was validated for linearity, accuracy, precision, limits of detection, and quantification. The calibration equation revealed a good linear relationship (r(2) = 0.998-0.999). Sufficient recovery was observed in the range of 96.3-99.5%. The method showed good reproducibility with intra- and interday precision of 0.97 and 1.76%, respectively. The quantification limits for the compounds were in the range of 477.0-479.8 ng/mL. The proposed method was applied to the analysis of real serum samples.

Cyclic imides as potent and selective alpha-1A adrenergic receptor antagonists.

We disclose a new compound class of potent and selective alpha-1A adrenergic receptor antagonists exemplified by the geminally, disubstituted cyclic imide 7. The optimization of lead compounds resulting in the cyclic imide motif is highlighted. The results of in vitro and in vivo studies of selected compounds are presented.

Individualized dosing of amonafide based on a pharmacodynamic model incorporating acetylator phenotype and gender.

Amonafide is extensively metabolized, including conversion by N-acetylation to an active metabolite. Our previous studies have shown that fast acetylators of amonafide have increased toxicity, and we have recommended doses of 250 and 375 mg m-2 day-1 for 5 days, for fast and slow acetylators, respectively. Despite phenotype-specific dosing, significant variability in leukopenia persisted. The goal of this study was to construct and validate a pharmacodynamic model-based dosing strategy for amonafide, to try to further decrease inter-patient variability in leukopenia. The model was based on a training data set of 41 patients previously treated with amonafide. The first cycle nadir WBC was modelled as a function of dose, acetylator phenotype and baseline patient factors. This model was validated prospectively on patients similar to those in our previous studies. Based on the training data set, the optimal model was defined by three factors: acetylator phenotype, gender, and pretreatment WBC. Using this model and a target WBC nadir of 1700 microliters-1, six dosing strata were prospectively evaluated. A total of 24 fast acetylators received either 238 or 276 mg m-2 day-1 and 20 slow acetylators received between 345 and 485 mg m-2 day-1. The mean (+/- SE) error (deviation from target nadir) was 430 (+/- 240) cells microliters-1. Submaximal treatment (yielding grade 0-1 leukopenia) was limited to 20% of patients, while 55% experienced grade 2-3 toxicity. A complex dosing strategy for amonafide is feasible, employing prospective acetylator phenotyping, model-guided dosing, and adaptive control.

Population pharmacodynamic study of amonafide: a Cancer and Leukemia Group B study.

PURPOSE: To determine if variability in toxicity of amonafide during phase II trials could be correlated with pharmacokinetic variability. PATIENTS AND METHODS: Seventy-three patients enrolled onto three Cancer and Leukemia Group B (CALGB) phase II trials of amonafide (300 mg/m2 daily for 5 days) were studied, using a limited sampling strategy (45 minutes and 24 hours) to estimate the amonafide area under the plasma concentration-time curve (AUC). Concentrations of N-acetyl-amonafide, an active metabolite, were also determined. RESULTS: The primary determinant of toxicity at a fixed dose of amonafide was the extent of N-acetylation. Fast acetylators (36% of patients) had significantly greater toxicity than slow acetylators (64% of patients), with median WBC nadirs of 500/microL and 3,400/microL, respectively (P < or = .001). In a multivariate analysis, lower pretreatment WBC count, lower albumin level, and nonwhite race were also independently associated with toxicity. Further analysis of interracial differences demonstrated that minority women had slower clearance of amonafide (P = .026) and a higher incidence of grade 4 leukopenia (P = .042). CONCLUSION: The highly variable toxicity of amonafide is primarily due to genetic differences in N-acetylation. Other genetic (race) and acquired factors (baseline WBC count and albumin level) also appear to influence the extent of toxicity observed following administration of this agent.

Reaction of dimethyl-3,3'-dithiobispropionimidate with intact human erythrocytes. Cross-linking of membrane proteins and hemoglobin.

Dimethyl-3,3'-dithiobispropionimidate penetrates intact human erythrocytes and cross-links many of the membrane proteins to hemoglobin as well as to each other. The cross-linked complexes so produced have been analyzed by both one- and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, making use of the easy cleavability of the disulfide-containing reagent. The basic pattern of cross-linked complexes appears identical with that seen with unsealed ghosts. Although subtle relative motions cannot be ruled out, no rearrangement of nearest neighbor peptide chains, on a scale that would alter the cross-linking pattern, occurs during osmotic lysis of erythrocytes. Superimposed on the basic pattern was a series of complexes involving globin chains. Bands 1, 2, 2.2, 2.4, 3, 4.1, 4.2, 6, and 7 (nomenclature of Steck, T.L. (1972) J. Mol. Biol. 66, 295-305) are all cross-linked to hemoglobin. Bands 2.2 and 2.4, recently shown to be accessible to the external surface of the membrane (Staros, J. V., and Richards, F. M. (1974) Biochemistry 13, 2720-2726), may be transmembrane proteins on the basis of the present findings. Band 5 is the only major band to show no detectable complexes with hemoglobin; oligomers of Band 5 itself, however, are seen. The absence of hemoglobin/Band 5 cross-linking in this case could reflect a special, as yet unexplained, environment for the Band 5 peptide. The amount of Band 6 in isolated membranes diminishes with increasing reagent concentration.