Advancing toxicology in RiskMAPP: setting ADEs based on the subsequent drug substance.

Cleaning validation programs are developed to demonstrate acceptable carryover of drug substances/products when multiple drug substances are manufactured in shared process equipment. The International Society of Pharmaceutical Engineers (ISPE) developed a guidance document in 2010 describing the Risk-Based Manufacture of Pharmaceutical Products (referred to as RiskMAPP) (ISPE, 2010). This guidance document developed the concept of an acceptable daily exposure (ADE), which is the toxicologically acceptable daily dose for the first drug substance used in processing drug equipment (DS(A)) without prior knowledge of the subsequent drug substance (DS(B)). This paper discusses an extension of the ADE methodology called the product-specific ADE (PSADE) which is derived when DS(B) is known. Four case studies demonstrate examples in which the PSADE can be scientifically supported in lieu of the ADE and highlight some limitations in its application. The PSADE approach can be used to justify higher acceptance limits for cleaning validation when the ADE based acceptance limits are below the process capability limit of the cleaning process or limit of quantitation of the analytical method.

Multiproduct Resin Reuse for Clinical and Commercial Manufacturing-Methodology and Acceptance Criteria.

Chromatography resins used for purifying biopharmaceuticals are generally dedicated to a single product. In good manufacturing practice (GMP) facilities that manufacture a limited amount of any particular product, this practice can result in the resin being used for a fraction of its useful life. A methodology for extending resin reuse to multiple products is described. With this methodology, resin and column performance, product carryover, and cleaning effectiveness are continually monitored to ensure that product quality is not affected by multiproduct resin reuse (MRR). Resin and column performance is evaluated in terms of (a) system suitability parameters, such as peak-shape and transition, and height equivalent theoretical plate (HETP) data; (b) key operating parameters, such as flow rate, inlet pressure, and pressure drop across the column; and (c) process performance parameters, such as impurity profiles, product quality, and yield. Historical data are used to establish process capability limits (PCLs) for these parameters. Operation within the PCLs provides assurance that column integrity and binding capacity of the resin are not affected by MRR.Product carryover defined as the carryover of the previously processed product (A) into a dose of the subsequently processed product (B) (COA→B), should be acceptable from a predictive patient safety standpoint. A methodology for determining COA→B from first principles and setting acceptance limits for cleaning validation is described.Cleaning effectiveness is evaluated by performing a blank elution run after inter-campaign cleaning and prior to product changeover. The acceptance limits for product carryover (COA→B) are more stringent for MRR than for single-product resin reuse. Thus, the inter-campaign cleaning process should be robust enough to consistently meet the more stringent acceptance limits for MRR. Additionally, the analytical methods should be sensitive enough to adequately quantify the concentration of the previously processed product (A) and its degradants in the eluent.General considerations for designing small-scale chromatographic studies for process development are also described. These studies typically include process-cycling runs with multiple products followed by viral clearance studies with a panel of model viruses. Small-scale studies can be used to optimize cleaning parameters, predict resin performance and product quality, and estimate the number of multiproduct purification cycles that can be run without affecting product quality. The proposed methodology is intended to be broadly applicable; however, it is acknowledged that alternative approaches may be more appropriate for specific scenarios.LAY ABSTRACT: Chromatography resins used for purifying biopharmaceuticals are generally dedicated to a single product. In good manufacturing practice (GMP) facilities that make a limited amount of any particular product, this practice can result in the resin being used for a fraction of its useful life. A methodology for extending resin reuse to multiple products is described. With this methodology, resin and column performance, product carryover, and cleaning effectiveness are continually monitored to ensure that product quality is not affected by multiproduct resin reuse.General considerations for designing small-scale chromatographic studies for process development are described. These studies typically include process-cycling runs with multiple products followed by viral clearance studies with a panel of model viruses. Small-scale studies can be used to optimize cleaning parameters, predict resin performance and product quality, and estimate the number of multiproduct purification cycles that can be run without impacting product quality.The proposed methodology is intended to be broadly applicable; however, it is acknowledged that alternative approaches may be more appropriate for specific scenarios.

Microbial ingress through breaches in aseptic manufacturing systems: experimental investigation of pressure-driven leaks of liquids.

The ability of pressure-driven leaks to provide an effective barrier against microbial ingress was investigated experimentally. The leak was simulated by circulating growth promoting media through a section of flexible tubing that had a 3/4-inch breach. The flow rate of the media was adjusted until the leak was barely visible; the leak rate was minimized to enhance the possibility of microbial ingress through the breach. The site of the breach was repeatedly inoculated with an actively growing population of Pseudomonas aeruginosa--a highly motile bacterium--suspended in a nutrient-rich medium. The breach was exposed to approximately 140 million organisms over a period of 8 h. This level of contamination greatly exceeds the microbial exposure that a breach would be subjected to in an aseptic manufacturing environment. The data show that microbial ingress did not occur under the above conditions. This indicates that pressure-driven leaks in flexible tubing can provide an effective barrier against microbial ingress, and that the integrity of the sterile boundary can be maintained during such leaks. The results of this investigation could be used to perform risk assessment analyses of the potential for microbial ingress through breaches in aseptic manufacturing systems.

In situ monitoring of soil dissolution dynamics: a rapid and simple method for determining worst-case soils for cleaning validation.

A common approach utilized in validating the cleaning of multi-product equipment is to challenge the cleaning cycle with the hardest-to-clean, or "worst-case", soil. The worst-case soil is often determined through bench-scale experiments. These experiments can be tricky and time-consuming, especially when the dissolution dynamics of the soils are characterized by crossovers beyond the limit of visual detection. This paper describes a simple in situ method for monitoring soil dissolution dynamics and rapidly determining worst-case soils for cleaning validation. The method utilizes the real-time response of electrical conductivity to identify crossovers and to determine the optimal time for endpoint analysis. The results address the sensitivity and reproducibility of the method and the identification of critical experimental parameters. The dissolution dynamics of several parenteral products are compared.