LOSS OF QUINIDINE GLUCONATE INJECTION IN A POLYVINYL-CHLORIDE INFUSION SYSTEM

The effect of a polyvinyl chloride (PVC) i.v. administration system on the availability of quinidine gluconate was studied. Quinidine glucon ate diluted in 5% dextrose injection was administered intravenously to five healthy volunteers via conventional PVC infusion sets, and the s ubjects received oral quinidine sulfate two days later. The mean +/- S .D. oral bioavailability of quinidine was, un unexpectedly, greater th an 100% (147 +/- 44%). To test the possibility that this occurred beca use of reduced delivery of i.v. quinidine, the percentage of drug deli vered via two systems was evaluated in simulation studies, one involvi ng a conventional PVC administration set and the other a glass syringe attached to shorter PVC tubing and a winged i.v. catheter. Spectropho tometric analysis revealed a 5-7% reduction in absorbance associated w ith loss of quinidine in the PVC infusion bag and a further 34-38% red uction in absorbance attributable to quinidine loss in the PVC tubing. However, with the winged i.v. catheter system the loss was reduced to less than 3%. More than 40% of a dose of quinidine gluconate was lost when the drug was administered with a conventional PVC i.v. administr ation set. Drug loss was reduced by using a winged i.v. catheter and s horter tubing.