Prediction of drug loss from PVC infusion bags

PVC:water partition coefficients for a series of 13 drugs have been calculated from literature data and a high degree of correlation with octanol:water partition coefficients demonstrated. The resulting model, log PPVC = -0.35 + 0.69 log P. (r2 = 0.88) has been prospectively tested with 10 drugs. All the test drugs were within the 95% confidence intervals associated with predicted log PPVC values consistent with a valid model. In practice, predicted log PPVC values may be used to estimate drug loss from the aqueous phase of PVC bags at equilibrium. Equations are described which enable calculation of likely drug loss from 100, 500 and 1000 mL PVC bags. It is recommended that this approach is used to identify drugs which are unlikely to be significantly absorbed into PVC.