This proposed revision provides guidance on the selection and implementation of assay methodologies to serve as alternatives to compendial microbiological methods. The revised chapter describes important steps that should be taken to evaluate candidate alternative methods, to select the analytical technology, and ultimately to qualify the method with actual product. These steps include, but are not limited to, identification of a potentially suitable alternative methodology, demonstration that the method is equivalent and applicable as a replacement for a standard compendial method, development of user specifications for equipment selection, and qualification of the method in the laboratory. In addition, this chapter outlines four distinct options for demonstrating equivalence.
A separate draft chapter, 1223.1, Validation of Alternative Methods to Antibiotic Microbial Assays, is also available for review and comment.
Microbiological assay methods are used to quantify the potency, or antimicrobial activity, of antibiotics. These microbial assays provide a direct measure of the effectiveness of the antibiotic against a reference microorganism. However, microbial assays have limited selectivity and are not appropriate for evaluating organic impurities. Also, the specific skill sets required for performing microbiological antibiotic assays, their unique equipment requirements, and their comparative complexity deter many stakeholders from using these methods. In contrast, physicochemical analytical procedures, such as high-performance liquid chromatography (HPLC), allow for simpler preparation and analysis of samples and rapid data acquisition with improved precision, accuracy, selectivity, and specificity. Alternative methods can be used effectively for both potency assignment and organic impurity testing. This proposed general chapter presents points to consider for stakeholders who wish to use physicochemical methods such as HPLC as alternatives to microbial assay methods described in general chapter Antibiotics—Microbial Assays 81.
The public can also provide comments on the draft 1223.1 until September 30, 2014.