Systemic bioavailability and pharmacokinetics of methylprednisolone in patients with rheumatoid arthritis following ‘high-dose’ pulse administration

✍ Scribed by P. K. Narang; R. Wilder; D. C. Chatterji; R. L. Yeager; J. F. Gallelli

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 781 KB
• Volume: 4
• Category: Article
• ISSN: 0142-2782
• DOI: 10.1002/bdd.2510040305

✦ Synopsis

The absolute and relative bioavailability of two methylprednisolone formulations (capsules and suspension) was determined along with its pharmacokinetics in -four arthritic female patients, following an unconventional high-dose pulse of 1 g. Plasma concentrations of the drug were measured by a sensitive and specific high-performance liquid chromatographic (HPLC) procedure. The disposition of methylprednisolone from plasma following intravenous (i.v.) infusion of its succinate ester appeared monoexponential with a mean half-life of 2.4 h and an apparent volume of distribution (V,,) of 50 1 (0.87 I/kg). The total body clearance (CI) averaged 15.12 I/h. Absolute bioavailability was assessed by comparing the areas under the plasma concentration time curves (normalized to dose) following oral administration of capsule or suspension with those of intravenous administration. N o significant difference (p > 0.2) was observed when systemic availability (,L expressed in per cent) following administration of drug in capsule ( f = 49.35 per cent) was compared with that obtained following the administration of drug in a suspension (.f = 58.26 per cent). The difference in the observed and predicted f m a y be due to incomplete absorption, hepatic and/or extrahepatic metabolism of methylprednisolone. Subjective evaluation showed no side effects of this high-dose pulse therapy in any of the patients.