Critical Aspects of pH Measurement for Bacteriostatic Water for Injection.

Bacteriostatic water for injection (bWFI) is a common diluent for parenteral pharmaceutical products. bWFI is sterile water for injection containing one or more suitable antimicrobial agents to suppress the growth of microbial contaminants. United States Pharmacopeia (USP) monograph describes bWFI with pH ranging from pH 4.5 to 7.0. Lacking buffering reagents, bWFI has very low ionic strength, no buffering capacity and is prone to sample contamination. These characteristics pose a challenge for accurate bWFI pH measurements which are characterized by long response times and noisy signals, resulting in inconsistent results. The challenging nature of bWFI pH measurement, however, is not fully recognized as pH is generally considered a routine analytical technique. Even with the addition of KCl to increase ionic strength as recommended by the USP bWFI monograph, variability in pH results is still observed without careful consideration of other critical measurement factors. To bring awareness to the challenges associated with bWFI pH measurement, we present a comprehensive characterization of the bWFI pH measurement process that includes an evaluation of probe suitability, measurement stabilization time, and pH meter settings. While these factors may be non-critical and sometimes overlooked when developing pH methods for buffered samples, they can have a significant impact on bWFI pH measurement. We present recommendations that can help reliable bWFI pH measurements for routine execution in a controlled environment. These recommendations also apply to other pharmaceutical solutions or water samples with low ionic strength.

Manufacturing Bacteriophages (Part 2 of 2): Formulation, Analytics and Quality Control Considerations.

Within this second piece of the two-part series of phage manufacturing considerations, we are examining the creation of a drug product from a drug substance in the form of formulation, through to fill-finish. Formulation of a drug product, in the case of bacteriophage products, is often considered only after many choices have been made in the development and manufacture of a drug substance, increasing the final product development timeline and difficulty of achieving necessary performance parameters. As with the preceding review in this sequence, we aim to provide the reader with a framework to be able to consider pharmaceutical development choices for the formulation of a bacteriophage-based drug product. The intent is to sensitize and highlight the tradeoffs that are necessary in the development of a finished drug product, and to be able to take the entire spectrum of tradeoffs into account, starting with early-stage R&D efforts. Furthermore, we are arming the reader with an overview of historical and current analytical methods with a special emphasis on most relevant and most widely available methods. Bacteriophages pose some challenges that are related to but also separate from eukaryotic viruses. Last, but not least, we close this two-part series by briefly discussing quality control (QC) aspects of a bacteriophage-based product, taking into consideration the opportunities and challenges that engineered bacteriophages uniquely present and offer.

Manufacturing Bacteriophages (Part 1 of 2): Cell Line Development, Upstream, and Downstream Considerations.

Within this first part of the two-part series on phage manufacturing, we will give an overview of the process leading to bacteriophages as a drug substance, before covering the formulation into a drug product in the second part. The principal goal is to provide the reader with a comprehensive framework of the challenges and opportunities that present themselves when developing manufacturing processes for bacteriophage-based products. We will examine cell line development for manufacture, upstream and downstream processes, while also covering the additional opportunities that engineered bacteriophages present.