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  • 1
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Chargeable cyclodextrins ; Ion pairing ; Separation of charged and uncharged enantiomeric drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chargeable cyclodextrins (CD’s) offer new possibilities for the separation of enantiomers in capillary electrophoresis. Carboxymethylated, carboxyethylated, and succinylated β-cyclodextrin were used in these experiments in two different modes. At low pH (〈pH 4) all carboxylic functions were protonated and the CD’s behaved as “quasi stationary phases”. At high pH (〉pH 5), deprotonation of the carboxylic functions lead to mobility of the negatively charged chiral selectors themselves. They acted then as micellar-like systems which can be described as “moving stationary phases”. Under these conditions the separation of uncharged enantiomers was possible. Additionally the capability of these cyclodextrins as ion-pairing agents for the separation of enantiomers with positive charges has also been investigated. Employing the same cyclodextrin in the charged and the uncharged modes (at high or low pH) the migration order of the enantiomers could be reversed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0843
    Keywords: Key words Chemotherapy ; Concurrent radiochemotherapy ; Etoposide ; Malignant gliomas ; Newly developed brain tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Etoposide, a semisynthetic derivative of podophyllotoxine, is a topoisomerase II inhibitor. This drug is currently used in several types of human cancer. The aim of this study was to evaluate the efficacity and tolerance of a near-concurrent association of radiotherapy and etoposide for newly malignant gliomas. Methods: From May 1995 to December 1996, 30 malignant glioma patients were included in this phase II study; 16 patients underwent surgical tumor resection, and a stereotactic biopsy was performed in 14 patients. Standard cranial irradiation and six courses of etoposide (100 mg/m2, ×days 1–3) were administered. The first course of etoposide was administered on days 1–3 of radiotherapy and was resumed in the week following the end of radiotherapy. Treatment was consolidated by further courses of etoposide every 4 weeks. Results: Only 26 patients could be evaluated for the purpose of our study. The median age was 60.1 years, and the median Karnofsky performance score (KPS) was 80.2. The rate of objective response for evaluable patients was 34.6%, and four complete responses (CR) and five partial responses (PR) were noted. The median survival (MST) was 12 months, and the average overall survival was 12.5 months. Hematological toxicity was mild, and grade 3 or 4 neutropenia (white blood cell count 〈1500/ml) was noted in three patients, without any sepsis or bleeding. Conclusions: The results obtained in this study are comparable to the best reported results on the combination of radiotherapy and nitrosoureas. The near-concurrent combination of radiotherapy and etoposide seems to be effective and well tolerated in the treatment of newly malignant gliomas.
    Type of Medium: Electronic Resource
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