Comparison of the Extraction Properties of Binary Polysorbate 80/Water and Isopropanol/Water Solutions for Organic Substances Originating from a Parenteral Infusion Pump

Evaluation of Two Cosolvency Models to Predict Solute Partitioning between Polymers (LDPE) and Water - Ethanol Simulating Solvent Mixtures

PURPOSE

Binary water - ethanol mixtures, by mimicking a clinically relevant medium's polarity-driven extraction strength, facilitate experimental modeling of patient exposure to chemicals which can potentially leach from a plastic material for pharmaceutical applications. Estimates of patient exposure could consequently benefit from a quantitative concept for tailoring the extraction strength of the simulating solvent mixture towards the one of the clinically relevant medium.

METHODS

The hypothetical partition coefficient based upon the differential solubility between water-ethanol mixtures and water, [Formula: see text], has been calculated by the log-linear model from Yalkowsky and coworkers and a cosolvency model based on Abraham-type linear solvation energy relationships (LSERs). Then, by applying a thermodynamic cycle using the partition coefficient LDPE/water, [Formula: see text], partitioning between LDPE and the ethanol in water mixture was calculated and experimentally verified for a wide array of chemically diverse solutes.

RESULTS

The partition coefficients between LDPE and volume fractions of 0.1, 0.2, 0.35 and 0.5 of ethanol in water calculated by this approach correlated well with experimentally obtained values. The LSER based model was found slightly superior over the log-linear cosolvency model.

CONCLUSIONS

Solubilization strength projection by means of cosolvency models in combination with LSER predicted partition coefficients LDPE/water enable the tailored preparation of water-ethanol simulating solvent mixtures when input parameters from the clinically relevant medium are available. This approach can increase the reliability of patient exposure estimations and avoid overly complex extraction profiles, thus minimizing time and resources for chemical safety risk assessments on plastic materials used in pharmaceutical applications.

Comparison of the Levels of Rubber Stopper-Related Organic Leachables in Commercially Available Vialed Liquid and Lyophilized Drug Products

PURPOSE

Rubber stoppers that seal the primary packaging systems of parenteral pharmaceutical products have the potential to introduce impurities into the drug during storage. While this interaction has been well characterized for products stored as an aqueous liquid, it is not well understood how the interaction is affected when the product is stored as a lyophilized solid. Accordingly, the goal of this study was to determine how lyophilization affects the propensity for impurity migration (leaching) into the product.

METHODS

The concentration of substances in the stopper and the concentration of these substances that had leached into the product at equilibrium were measured and used to calculate equilibrium constants, which quantifies the degree of partitioning of each compound between each unique stopper and drug matrix, for twelve lyophilized and twelve liquid commercial drug products.

RESULTS

Lyophilized products were shown to have a significantly increased propensity to contain substances that migrated from their stopper as compared to liquid products, as supported both by the general qualitative/quantitative leachable profile and the equilibrium constants obtained.

CONCLUSIONS

The conversion of a liquid drug formulation to a lyophilized solid during storage will increase the number and concentration of impurities leached from the stopper.