Best Practices for Microbial Challenge In-use Studies to Evaluate the Microbial Growth Potential of Parenteral Biological Products; Industry and Regulatory Considerations.

Microbial challenge in-use studies are performed to evaluate the potential for microbial proliferation in preservative-free single dose biological products after first puncture and potential accidental contamination during dose preparation (e.g. reconstitution, dilution) and storage. These studies, in addition to physicochemical in-use stability assessments, are used as part of product registration to define in-use hold times in Prescribing Information and in the pharmacy manual in the case of clinical products. There are no formal guidance documents describing regulator expectations on how to conduct microbial challenge in-use studies and interpret microbial data to assign in-use storage hold-times. In lieu of guidance, US Food and Drug Administration (FDA) regulators have authored publications and presentations describing regulator expectations. Insufficient or unavailable microbial challenge data can result in shortened in-use hold times, thus microbial challenge data enables flexibility for health care providers (HCPs) and patients, while ensuring patient safety. A cross-industry/FDA in-use microbial working group was formed through the Innovation & Quality (IQ) Consortium to gain alignment among industry practice and regulator expectations. The working group assessed regulatory guidance, current industry practice via a blinded survey of IQ Consortium member companies, and scientific rationale to align on recommendations for experimental design, execution of microbial challenge in-use studies, and a decision tree for microbial data interpretation to assign in-use hold times. Besides the study execution and data interpretation, additional considerations are discussed including use of platform data for clinical stage products, closed system transfer devices (CSTDs), transport of dose solutions, long infusion times, and the use of USP <797> by HCPs for preparing sterile drugs for administration. The recommendations provided in this manuscript will help streamline biological product development, ensure consistency on assignment of in-use hold times in biological product labels across industry, and provide maximum allowable flexibility to HCPs and patients, while ensuring patient safety.

An Industry Perspective on the Challenges of Using Closed System Transfer Devices with Biologics and Communication Guidance to Healthcare Professionals.

Closed system transfer devices (CSTDs) have been used with hazardous drugs for several decades. The goal of this whitepaper is to increase awareness among healthcare professionals, device manufacturers, regulators, and pharmaceutical/biotech companies on the potential issues around the use of CSTDs with biologic drug products to allow their informed use in clinics. Specifically, we discuss the key topics related to the use of CSTDs with biologics products, including components and materials of construction, a breakdown of regulatory, technical, clinical site-related risks and challenges associated with the use of CSTDs with biological products, gathered from stakeholder discussion at the IQ CSTD workshop, and considerations on current testing requirements and communication strategies to drive further dialog on the appropriate use of CSTDs. Given the technical challenges of using CSTDs with biologics, coupled with the current regulations surrounding CSTD approval and proper use, as well as a need for alignment and standardization to enable a consistent strategy for compatibility testing and communication of incompatibilities, it is recommended that global health authorities and other stakeholders seek to understand these issues, in order to alleviate these problems and keep healthcare workers and patients safe from harm.

A Mechanistic Understanding of Polysorbate 80 Oxidation in Histidine and Citrate Buffer Systems-Part 2.

In our previously published work, we reported rapid polysorbate 80 (PS80) oxidation in a histidine buffer after brief exposure to stainless steel and the ability of citrate and EDTA to prevent this oxidation. The focus of our current study was to mechanistically understand PS80 oxidation by studying the impacts of temperature, light, and stainless steel and the role of citrate and EDTA. Additionally, PS80 oxidation was studied in three different buffer systems: histidine, citrate, and phosphate. When the PS80-containing buffers in glass containers were exposed to the elevated temperature of 50°C, no PS80 oxidation was observed in either the histidine or the citrate buffer systems after 30 days; however, PS80 oxidation was observed in the phosphate buffer system within 14 days. These results demonstrated that temperature does not initiate PS80 oxidation in the histidine or the citrate buffer systems, but it may be a factor in the phosphate buffer system. When the three buffer systems containing PS80 were exposed to 20%, 50%, or 100% ICH Q1B light conditions and subsequently incubated in the dark at 50°C, the PS80 in the phosphate buffer system underwent oxidation within 7 days, whereas the PS80 in the histidine and the citrate buffer systems showed oxidation products only after 14 and 35 days, respectively. PS80 in the phosphate buffer system seemed to be the most vulnerable to light as PS80 in both the histidine and the citrate buffer systems underwent oxidation to a lesser extent, with faster oxidation occurring in the histidine buffer system than in the citrate buffer system. Finally, the ability of citrate and EDTA to act as not only chelators but also radical quenchers/scavengers was demonstrated when a metal ion, Fe2+, was spiked into the histidine buffer containing PS80. While radicals could not be unambiguously identified by NMR or EPR, the observation of PS80 oxidation products indicated their presence.LAY ABSTRACT: In our previously published work, we reported rapid polysorbate 80 (PS80) oxidation in a histidine buffer after brief exposure to stainless steel and the ability of citrate and EDTA to prevent this oxidation. The focus of our current study was to mechanistically understand PS80 oxidation by studying the impacts of temperature, light, and stainless steel and the role of citrate and EDTA. Additionally, PS80 oxidation was studied in three different buffer systems: histidine, citrate, and phosphate. The temperature study demonstrated that PS80 oxidation in the histidine or the citrate buffer systems is not initiated by temperature, but may be a factor in the phosphate buffer system. PS80 in the phosphate buffer system seemed to be the most vulnerable to light, as PS80 in both the histidine and the citrate buffer systems underwent oxidation at a lower level, with the histidine buffer system showing more rapid oxidation than the citrate buffer system. Finally, the ability of citrate and EDTA to act as not only chelators but also radical quenchers/scavengers was demonstrated when a metal ion, Fe2+, was spiked into the histidine buffer containing PS80. While neither NMR nor EPR could definitively identify the presence of free radicals, the observation of PS80 oxidation products indicates that they were present.

Impact of Stainless Steel Exposure on the Oxidation of Polysorbate 80 in Histidine Placebo and Active Monoclonal Antibody Formulation

Rapid oxidation of polysorbate 80 in histidine buffer was observed upon brief exposure to stainless steel. Liquid chromatography-mass spectrometry analysis indicates degradation of both polyoxyethylene sorbitan and polyoxyethylene head groups and unsaturated fatty acid chains, with further confirmation by reversed-phase high-performance liquid chromatography data. Both Fe2+ and Fe3+ were shown to induce polysorbate 80 oxidation. The degree of oxidation in polysorbate 20 and polysorbate 80 are comparable for the head groups and saturated fatty acid esters. However, the same phenomenon was not observed with placebo or monoclonal antibody at a threshold protein concentration, formulated in sodium citrate, in combination with histidine and sodium citrate, or with Na2 ethylenediaminetetraacetic acid (EDTA). Further, polysorbate 80 oxidation was not observed with Lilly's antibody containing the active ingredient LY2951742, at or above a threshold concentration. Finally, no major polysorbate 80 degradation was observed in histidine buffer, with or without protein, in containers composed of glass or plastic, or when stainless steel exposure was otherwise completely absent. Finally, the 2-oxo oxidation form of histidine was not observed, but the other oxidation products and modifications of histidine were identified.LAY ABSTRACT: Rapid oxidation of polysorbate 80 in histidine buffer was observed upon brief exposure to stainless steel. The degree of oxidation in polysorbate 80 and polysorbate 20 were comparable. However, the same phenomenon was not observed with placebo when formulated in sodium citrate, in combination with histidine and sodium citrate, or with Na2 ethylenediaminetetraacetic acid (EDTA). Polysorbate 80 oxidation was not observed with Lilly's antibody containing the active ingredient, LY2951742, at or above a threshold concentration. No major polysorbate 80 degradation in histidine buffer was observed when stainless steel contact was completely absent.

Impact of Drug Formulation Variables on Silicone Oil Structure and Functionality of Prefilled Syringe System.

Use of prefilled syringes to self-administer biologics via subcutaneous administration provides convenience to patients. The barrel interior of prefilled syringes is typically coated with silicone oil for lubrication to aid plunger movement at the time of administration. This study intended to evaluate the impact of formulation variables on the silicone oil on the barrel interior surface. Characterization techniques including syringe glide force, break loose force, Schlieren imaging, contact angle, inductively coupled plasma spectrometry, and thin film interference reflectometry were used in assessing the interactions. Data indicated that formulation variables such as pH, buffer/tonicity agent type and concentration, and surfactant present in the formulation can effect silicone oil lubrication of prefilled syringes, leading to changes in functional properties of the syringe over time. Syringe samples containing acetate and histidine buffers showed an increase in glide force at accelerated storage temperature conditions, but the change was minimal at 5 °C. The samples with the highest glide force correlated with the presence of mannitol in combination with sodium acetate buffer. Sodium chloride had lesser impact on glide force than mannitol. Samples with higher glide force exhibited a substantial change in the silicone oil layer of the syringe, as observed with Schlieren imaging, as well as a significant reduction in surface hydrophobicity, as demonstrated through contact angle measurement. These data indicated that the structure of the siliconized surface can change over time in contact with different formulations. During formulation development of drug products in prefilled syringes, in addition to potential impact on molecule stability, the selection of formulation variables should also be guided by assessing the impact to syringe functionality with the glide force as one of the key parameters.LAY ABSTRACT: Self-administering drug products packaged in prefilled syringes provides convenience to patients. The interior of a prefilled glass syringe is typically lubricated with silicone oil for easy plunger movement during injection. This article discusses the impact of formulation excipients on silicone oil coating inside the syringe. Characterization techniques were used to assess the ease of plunger movement and structure of the silicone coating. Data indicate formulation excipients can affect silicone oil distribution of prefilled syringes, leading to an increase in plunger glide force at accelerated storage temperature conditions. The increase in glide force within a prefilled syringe with or without an auto-injector can have an impact on dose accuracy and user experience. Syringes with a higher plunger glide force appeared to exhibit a change over time in surface energy and structure of the silicone oil layer in contact with particular formulations.

Physical and chemical compatibility of drotrecogin alfa (activated) with 34 drugs during simulated Y-site administration.

PURPOSE: The physical and chemical compatibility of drotrecogin alfa (activated) (recombinant human activated protein C) during simulated Y-site administration with drugs commonly used to treat patients with severe sepsis was determined. METHODS: Thirty-four drugs were investigated for visual compatibility with drotrecogin alfa, and included cardiovascular agents, conscious sedative agents, antibiotics, blood products, and other supportive care drugs. The physical and chemical compatibility of drotrecogin alfa with these drugs was determined using a well-established experimental model to simulate Y-site administration. Drotrecogin alfa (activated) was prepared as 100- and 1000-microg/mL solutions in 0.9% sodium chloride injection. All other drugs were prepared at maximum concentrations commonly administered in the clinical setting. Visual compatibility was assessed by visual inspection (observations of haziness, color change, or precipitate formation) and pH measurement at 0, 30, 60, and 240 minutes after mixing. RESULTS: Of the 34 test drugs, 8 were defined as visually compatible with drotrecogin alfa; these drugs were further assessed for chemical compatibility with drotrecogin alfa. The protein content, potency, and purity of drotrecogin alfa were determined at 0, 60, and 240 minutes after Y-site mixing as indicators of chemical compatibility. Six drugs (ceftriaxone, cisatracurium, fluconazole, nitroglycerin, potassium chloride, and vasopressin) were determined to be chemically compatible with drotrecogin alfa; two drugs (cyclosporine and ticarcillin-clavulanate) were chemically incompatible with drotrecogin alfa after Y-site mixing. CONCLUSION: Ceftriaxone, cisatracurium, fluconazole, nitroglycerin, potassium chloride, and vasopressin were physically and chemically compatible with drotrecogin alfa in a simulated Y-site infusion; 28 other drugs were incompatible with drotrecogin alfa.