Summary
The binding of melphalan to plasma proteins from four healthy humans and from rats was measured by centrifugal ultrafiltration. Melphalan concentrations were determined by HPLC and by measuring 14C-melphalan activity. In whole blood, melphalan was distributed preferentially in plasma. However, a constant fraction, 37%, which was independent of the total melphalan concentration in whole blood, was present within the red blood cells. The binding of melphalan to plasma proteins from humans was less than that from rats. In both, however, the fraction bound was constant throughout the concentration range (0.1 to 9.0 µM) that is achieved during standard-dose melphalan therapy. Albumin was the primary binding protein. At concentrations equal to or in excess of 33 µM, which have been achieved during high-dose melphalan therapy, free plasma melphalan concentrations were no longer linearly related to total drug concentrations, and the plasma protein binding of melphalan in the human became concentration dependent. This occurred at concentrations of 70 µM in the rat. Scatchard analysis of the data indicated the presence of 2 groups of binding sites. Class I sites had 0.03 and 0.4 binding sites per albumin molecule in humans and rats, with respective association constants of 4.43 × 104M−1 and 1.92 × 104M−1. Class II sites had 5.18 and 2.60 binding sites per molecule, with repective association constants of 3.82 × 102M−1 and 2.01 × 102M−1.
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Abramson F, Jenkins J, Ostchega Y (1982) Effects of cancer and its treatment on plasma concentrations of α1-acid glycoprotein and propanolol binding. Clin Pharmacol Ther 32: 659–663
Ahmed A, Hsu T, El-Azhary R, Moawad H, Costanzi J (1982) Macromolecular interactions of [14C-ring] melphalan in blood. Biochem Pharmacol 31: 1615–1619
Alberts D, Chang S, Chen S, Moon T, Evans T, Furner R, Himmelstein J (1979) Kinetics of intravenous melphalan. Clin Pharmacol Ther 26: 73–80
Ardiet C, Tranchand B, Biron P, Rebattu P, Philip T (1986) Pharmacokinetics of high-dose intravenous melphalan in children and adults with forced diuresis. Cancer Chemother Pharmacol 16: 300–305
Bosanquet A, Gilbey E (1982) Pharmacokinetics of oral and intravenous melphalan during routine treatment of multiple myeloma. Eur J Cancer Clin Oncol 18: 355–362
Casten D, Bodenhumer M, Burcham J (1943) A study of plasma protein variation in surgical procedure. Ann Surg 117: 52–73
Chang S, Alberts D, Farquhar D, Melnick L, Walson P, Salmon S (1978) Hydrolysis and protein binding of melphalan. J Pharm Sci 67: 682–684
Chang S, Alberts D, Melnick L, Walson P, Salmon S (1978) High-pressure liquid chromatographic analysis of melphalan plasma. J Pharm Sci 67: 679–682
Chirigos M, Mead J (1964) Experiments on determination of melphalan by fluoresence. Interaction with protein and various solutions. Anal Biochem 7: 259–268
Cornbleet M, Leonard R, Smyth J (1984) High-dose agent therapy: A review of clinical experiences. Cancer Drug Delivery 1: 227–238
Cornbleet M, McElwain T, Kumar P, Filshie J, Selby P, Carter R, Hedley D, Clark M, Millar J (1983) Treatment of advanced melanoma with high-dose melphalan and autologous bone marrow transplatation. Br J Cancer 48: 329–334
Doumas B, Watson W, Biggs H (1971) Albumin standards and the measurement of serum albumin with bromcresol green. Clin Chim Acta 31: 87
Dunnett C (1964) New tables for multiple comparisons with a control. Biometrics 20: 482–491
Ehrrson H, Lonroth U (1982) Degradation of melphalan in aqueous solutions; influence of human albumin binding. J Pharm Sci 71: 826–827
Evans T, Chang S, Alberts D, Sipes I, Brendel K (1982) In vitro degradation of L-phenylalanine mustard. Cancer Chemother Pharmacol 8: 175–178
Fisher B, Carbone P, Economons S (1975) L-Phenylalanine mustard in the management of primary breast cancer. A report of early findings. N Engl J Med 292: 117–122
Flora K, Smith S, Cradock J (1979) Application of a simple high-performance liquid chromatographic method for the determination of melphalan in the presence of its hydrolysis products. J Chromatogr 177: 91–97
Furner R, Brown R, Duncan G (1977) Pharmacokinetics of the absorption, distribution and elimination of melphalan (NSC-8806) in the dog. Cancer Treat Rep 61: 1637–1646
George R, Doth J, Gordon D (1972) Multiple myeloma-intermittent combination chemotherapy compared to continous therapy. Cancer 29: 1665–1670
Gornall A, Bradawill C, David M (1949) Determination of serum proteins by means of biuret reagent. J Biol Chem 177: 751
Gouyette A, Hartmann O, Pico J (1986) Pharmacokinetics of high-dose melphalan in children and adults. Cancer Chemother Pharmacol 16: 184–189
Hersh M, Ludden T, Kuhn J. Knight W (1983) Pharmacokinetics of high dose melphalan. Invest New Drugs 1: 331–334
Herzig R, Lazarus H, Forman W, Rekate H, Lowder J, Ingalls S (1981) Central nervous system penetration of high dose intravenous L-phenylalanine mustard. Proc Am Soc Clin Oncol 22: 531
Jackson P, Tucker J, Woods H (1982) Altered plasma binding in cancer: Role of α1-acid glycoprotein and albumin. Clin Pharmacol Ther 32: 295–302
Jusko W, Gretch M (1976) Plasma and tissue protein binding of drugs in pharmacokinetics. Drug Metabol Rev 5: 43–140
Knott G (1979) M-Laba mathematical modeling tool. Comput Prog Biomed 10: 271–280
Kyle R (1975) Multiple myeloma review of 869 cases. Mayo Clin Proc 50: 29–40
Martin B (1965) Potential effect of the plasma proteins on drug distribution. Nature 207: 274–276
Midler G, Alling E, Morton J (1950) Effect of neoplastic and allied diseases on concentration of plasma proteins. Cancer 3: 56–65
Miller R (1966) Simultaneous statistical inference, McGraw-Hill, New York, pp 76–81
Piver M, Barlow J, Lee F (1975) Sequential therapy for advanced ovarian adenocarcinoma: Operation, chemotherapy, second-look laparotomy and radiation therapy. Am J Obstet Gynecol 122: 355–357
Rosin R, Westbury G (1980) Isolated limb perfusion for malignant melanoma. Practitioner 224: 1031–1036
Ross W (1962) Alkylating agents. Biological alkylating agents. Butterworths, London, pp 3–31, 95–193
Scatchard G (1949) The attraction of proteins for small molecules and ions. Ann NY Acad Sci 51: 660–672
Steele W, Lawrence J, Stuart J, McNeil C (1979) The protein binding of methotrexate by the serum of normal subjects. Eur J Clin Pharmacol 15: 363–366
Steinfeld J (1960) I131 albumin degradation in patients with neoplastic diseases. Cancer 13: 974–984
Sweeney D, Greig N, Rapoport S (1985) High-performance liquid chromatography analysis of melphalan in plasma, brain and peripheral tissue by o-phthaladehyde derivatization and fluorescence detection. J Chromatogr 339: 434–439
Thorp J (1972) Inter and intra species differences in the binding of anionic compounds to albumin. Exerpta Medica Int Congr Ser 254: 98–109
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Greig, N.H., Sweeney, D.J. & Rapoport, S.I. Melphalan concentration dependent plasma protein binding in healthy humans and rats. Eur J Clin Pharmacol 32, 179–185 (1987). https://doi.org/10.1007/BF00542192
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DOI: https://doi.org/10.1007/BF00542192