Traditionally, when the topic of medical device cleaning studies is approached, the focus is on sterility and biocompatibility aspects, including particulate analysis, bioburden, LAL, and cytotoxicity testing. The component that is often forgotten is the effect of the manufacturing process. This may include machining oils and lubricants, mold release agents, cleaning solvents, and other processing aids, all of which may have a negative impact on the performance of the medical device or put the patient at risk.
There is little guidance on how to address these issues to define what is “clean.” It is therefore important for companies to investigate the residuals, establish a baseline, and set acceptance parameters for medical device cleanliness to ensure that their products are safe, compliant and marketable.
Establishing a Baseline for Residuals
ASTM F2459-05 Chemical Residue by Gravimetric Analysis
This document provides a quantitative approach to the amount of residue on the surface of a metallic device when extracted with aqueous or organic solvents. The amount of residue is determined gravimetrically (by weight). No indication is made of the type of residue present. Volatiles and some semi-volatiles may be lost in the evaporation process.
NAMSA can help you answer complex questions about manufacturing residues and your product.
Our residual analysis programs may use:
- Fourier transform infrared spectroscopy (FTIR) analysis
- Gas chromatography (GC) analysis for volatiles or semi-volatiles
- High-performance liquid chromatography (HPLC) analysis for non-volatiles
- Ion chromatography, through use of a conductivity detector
- Total organic carbon (TOC) analysis
Regardless of the methods chosen, an effective residual analysis program is essential for maintaining an acceptable level of cleanliness for medical device manufacturers. Determination of residues depends on the analyte of interest, the substrate, and the conditions of the extraction process. To determine the effectiveness of the extraction procedure, an efficiency/recovery study may be performed. A proactive approach to establishing acceptance criteria and routine monitoring of this process can not only save time and money down the road, but also ensure the safety of the medical devices and reduce product liability.