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Clinical Pharmacology of Intramuscularly Administered l ‐Asparaginase
Author(s) -
HO D. H. W.,
YAP H. Y.,
BROWN N.,
BENJAMIN R. S.,
FRIEREICH E. J.,
BLUMENSCHEIN G. R.,
BODEY G. P.
Publication year - 1981
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1981.tb01752.x
Subject(s) - volume of distribution , intramuscular injection , medicine , pharmacology , distribution (mathematics) , pharmacokinetics , urine , enzyme , anesthesia , chemistry , biochemistry , mathematical analysis , mathematics
Clinical pharmacology of l ‐asparaginase was compared by intramuscular and intravenous injections in 12 patients with metastatic cancer or leukemia. Following a single intramuscular injection at the gluteal site of l ‐asparaginase (10,000 IU/m 2 ), the enzyme appeared in plasma as measured initially at 1 hour, but plateau levels were not reached in plasma until 14 to 24 hours after drug administration. The peak plasma level was 1.12 lU/ml, only one fourth of that seen when l ‐asparaginase was given intravenously at equal doses. However, the enzyme level decrease in the plasma after intramuscular injections was slower, with a half‐life of 46 hours, compared to 7 to 28 hours for intravenously administered drug. The apparent volume of distribution indicated that the intravenously injected enzyme was mostly distributed in plasma, whereas the intramuscularly injected enzyme yielded a much larger volume of distribution (63 versus 245 ml/kg). In addition, only 19 per cent of the intramuscularly injected dose was in plasma, and the area under the curve ( C × t ) was only 1/24 that by intravenous route (20 versus 487 IU/ml · hr). No enzyme was measurable in patients' urine samples collected for three days after intramuscular injections of the enzyme, and only a trace (less than 1 per cent) of the enzyme was detected in urine after intravenous administration.