Original Article: PDF OnlyPHARMACOKINETICS OF PAMIDRONATE DISODIUM IN CANCER PATIENTS AFTER A SINGLE INTRAVENOUS INFUSION OF 30-, 60− OR 90-mg DOSE OVER 4 OR 24 HOURSCheung, W. K.1; Brunner, L.1; Schoenfeld, S.2; Knight, R.2; Seaman, J.2; Brox, A.3; Batist, G.4; John, V.1; Chan, K.1Author Information 1Ciba-Geigy Corporation, Ardsley, NY 10502, USA. 2Ciba-Geigy Corporation, Summit, NJ, USA. 3Royal Victoria Hospital, Montreal, Canada. 4Montreal General Hospital, Montreal, Canada. American Journal of Therapeutics: October 1994 - Volume 1 - Issue 3 - p 228-235 Buy Abstract The objective of this study was to determine the pharmacokinetics of pamidronate disodium in plasma and urine after a single intravenous infusion of the drug to cancer patients at risk for developing bone metastases. Thirty-six patients were randomized into six treatment groups to receive 30-, 60− or 90-mg doses of the drug by 4− or 24-h intravenous infusions. Plasma and urine samples were collected at intervals for up to 144 h after drug administration and were assayed for pamidronate disodium using validated reversed-phase HPLC methods. The percentage of the administered dose excreted in urine following a 4− or 24-h infusion of 30-, 60− or 90-mg pamidronate disodium ranged from 30% to 60% except for one individual who excreted 96% by this route of elimination. There was a linear relationship between amount of drug excreted in urine and dose. Curve fitting of ARE (amount of drug to be excreted in urine) data indicated that the disposition kinetics of the drug was consistent with a biexponential process with overall mean ± S.D. half-life values of 2.1 ± 1.8 and 26.9 ± 8.7 h for the À and β phases, respectively. The results of this study showed that the drug exhibited dose proportionality in its pharmacokinetic behavior over the 30–90-mg range regardless of whether it was infused over a 4− or 24-h interval. © Williams & Wilkins 1994. All Rights Reserved.