Sustainability in the OR: reducing environmental impact and hospital specific waste by filtration of used cardioplegic solution to exclude active pharmaceutical ingredients before disposal

Abstract

A low-budget sustainable method was developed for the filtration and quantification of procaine in used cardioplegic solution. The quantification method consisted of reversed-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) using a 5 μm XSELECT CSH C18 column and UV-detection at 294 nm. The mobile phase was recycled during measurements to minimize liquid waste, except for the last three validation sets. The HPLC method was validated for procaine in cardioplegic solution spiked with fetal bovine serum. Metronidazole was used as an internal standard. Sample preparation consisted of protein precipitation with ice cold (-20 °C) acetonitrile followed by centrifugation at 7 °C. Then samples were diluted with water to acquire the needed concentrations. Dilution was followed by a second centrifuging step (at 7 °C) to minimize serum peaks. The limit of detection (LOD) was determined to be 0.073 μg/mL. The lower limit of quantification (LLOQ) was at 0.5 μg/mL. The linearity was proven for a range of 0.5 to 500 μg/mL (r2 = 1.0000 ). Accuracy and precision of the quality control (QC) samples were determined with an intra- and interday analysis. Accuracies intraday ranged from 86% to 109%, except for LLOQs of set 3 (>115%) in which mobile phase was recycled. Intraday precisions were all below 15% and for LLOQ all below 20%. The interday analysis showed that accuracies were all within limits at every QC level. The interday precisions were also all within limits at every QC level (<15% and <20% for LLOQ). The method for filtration of procaine was based on solid phase extraction (SPE) using activated carbon as a low-budget SPE material. The adsorption capacity of activated carbon for procaine in pharmaceutical solution was determined to be 74% for 100 mg of activated carbon. An estimated 1.5 grams of activated carbon would be required for filtration of one intravenous (IV) bag of cardioplegic solution. A cartridge filled with activated carbon has yet to be developed and tested on used cardioplegic solution. Ultimately, this validated method could be used as a stepping stone in order to develop a universal method for filtration of active pharmaceutical ingredients (APIs) in all kinds of perfusates.