Preventing Cross-Contamination during Lyophilization: GMP and Occupational Cleaning Requirements for Nonproduct and...

A detailed overview is provided for the possible patient exposure to highly potent active pharmaceutical ingredients (HPAPIs) from potential cross-contamination through the lyophilization process. The intent of this paper is to raise awareness of the risk(s) to patients and stimulate the implementation of adequate risk-based controls, such as containment process(es), use of adequate surrogates in cleaning validation/verification, and test method-sensitivity-based cleaning validation acceptance conditions. Although lyophilizers are considered to be nonproduct-contact surfaces because their surfaces and fixtures do not usually come into direct contact with the product, product contamination can occur at critical locations within a lyophilizer and/or during the unloading process. Contamination of the air because of released product particles can also create a risk. Therefore, special attention should be paid to HPAPIs, as the permitted daily exposures (PDEs) for patients are particularly low. During a lyophilizer cycle, areas of concern are spreading of the lyophilizer HPAPI powder because of air turbulence, contaminated plates, mechanical transfer systems, and spreading because of damaged vials or contaminated stainless steel or plastic surfaces. Specific considerations for contamination containment for the lyophilizer unloading process are presented. Suggestions are provided for the prevention of patient exposure through cross-contamination via direct-contact areas and prevention of manufacturing personnel exposure via non-direct-contact areas. A surface limit(s) of 1 PDE per square decimeter for nonproduct-contact surfaces inside a lyophilizer is proposed. Risk-based cleaning validation/verification strategies are discussed, with specific consideration of the quality control test method sensitivity expectations and use of suitable surrogates for lyophilized products in the cleaning verification studies.LAY ABSTRACT: This paper provides an overview of important points to consider during the manufacture of highly potent active pharmaceutical ingredients (HPAPI) with the intention to limit patient exposure and/or manufacturing personnel exposure to these highly toxic HPAPIs. HPAPI can potentially be spread during the freeze-drying process (lyophilization) and may cross-contaminate products. Manufacturing personnel and patients taking other freeze-dried products made in the same lyophilizer could be contaminated. It is therefore necessary to implement rigorous contamination controls. Within the lyophilizer, areas of concern are spreading of the lyophilizer HPAPI powder because of air turbulence, contaminated plates, mechanical transfer systems, and spreading because of damaged vials or contaminated stainless steel or plastic surfaces. Cleaning validation/verification studies, intended to demonstrate sufficient cleanability of the freeze-drying process as well as the recommended test method sensitivity to detect these highly toxic HPAPIs, are reviewed. Limits for the relevant production surface areas where cross-contamination and/or personnel exposure (through direct contact) could occur are proposed in this paper.