Polymeric materials are widely used in the construction of medical devices and drug handling systems which come into contact with liquid and powder pharmaceutical products before the dose is delivered to the patient. The absence of foreign material in the dose is important.
A pharmaceutical manufacturer was concerned about possible contamination of a solid drug formulation with trace amounts of plastics used in the powder handling equipment. Parts made from polycarbonate (PC), high impact polystyrene (HIPS) and poly(ethylene:vinyl acetate) (EVA) come into contact with the powder. It was important for the manufacturer to detect these polymeric materials in the final powder at the 50 ppm level.
The powder formulation contained organic solvent and water soluble ionic compounds whereas the PC, HIPS and EVA are organic soluble but water insoluble. After a preliminary evaluation of candidate approaches, FTIR turned out to be the analytical method of choice. Methylene chloride and carbon disulfide solutions of the three polymers were analyzed in a 10 mm path length cell. The absorbance value (‘intensity’) of a marker absorbance band unique to each polymer was measured and provided a linear correlation with that polymer’s concentration in dilute solution.
The results from the analysis of a control sample, listed in Table I, demonstrate that this method could provide accurate results with a minimum of sample preparation and exceeded the client’s requirement for detection sensitivity.
The results from a drug powder formulation prepared in the laboratory (‘Blank’) and a representative sample which had been passed through the powder handling device are shown in Table II.
While no EVA and HIPS were detected, the drug powder did contain 72 ppm PC.
Conclusion and Benefit to the Customer
Based in part on this analytical methodology, the client was able to modify the hardware and processing conditions to eliminate polymeric contamination in the solid drug which resulted in a saleable product.