Use of leftovers of monoclonal antibody products after partial extraction - A microbiological safety study.

BACKGROUND/PURPOSE: In the absence of thorough microbiological, chemical and physical stability data, high amounts of pharmaceutical products, from which the seal has been broken, are to be discarded after preparation. We performed a generic microbiological validation study for several marketed monoclonal antibody products, in order to define conditions under which leftovers from partially extracted product can be used in order to minimize loss. METHODS: From the daily practice of the Central Preparation Unit of the Netherlands Cancer Institute, used monoclonal antibody product vials were collected. To examine the integrity of the primary packaging, a VDT/S Vacuum Leak tester from Erweka was used. Vials were punctured with different types of spikes or a needle prior to experiments and examined for leakage afterward. In addition, microbiological monitoring was performed by broth simulation of the preparation method. RESULTS: All vials (631 vials, 18 different monoclonal antibody products) showed no leakage after puncturing with a 18 G needle. However, the use of a spike system resulted in leakage in 108 of the 435 tested vials. Results from the broth simulations confirmed a higher risk of contamination after puncturing with a spike as compared to needle-punctured vials (0.5% vs. 0.05%). CONCLUSION: When working under aseptic preparation conditions and making use of appropriate needle, the risk of contamination is acceptably low to justify storage and reuse of leftover monoclonal antibody product from a microbiological perspective. The spikes tested lead to an unacceptably high level of loss of integrity and subsequent risk of microbiological contamination if stored in a non-classified environment. We concluded that these results could be applied generically to all monoclonal antibody products with a primary packaging composed of a glass vial and rubber stopper.

Determining Maximum Allowable Rubber Stopper Displacement for Container Closure Integrity (CCI).

Sterile pharmaceuticals require they be developed and manufactured using suitable container closure systems to maintain sterility until product opening. Characterizing container closure integrity (CCI) in relation to rubber stopper displacement was controversially discussed during the Annex 1 revision process. An automated inspection system can reject units with displaced rubber stoppers, and the related acceptance criteria for such in-process testing can be established by adequate studies. In this manuscript, we describe a novel helium leak CCI testing method to study the relation of rubber stopper displacement and CCI. Ten different commonly used vial-rubber stopper combinations were characterized, which led to robust test results. Pronounced differences between the different vial-rubber stopper combinations were observed, clearly showing that the combination of different stoppers, vials, and caps led to significant differences in allowable stopper displacement for routine manufacture.

Anomalous behavior of mannitol hemihydrate: Implications on sucrose crystallization in colyophilized systems.

When solutions containing mannitol and sucrose are freeze-dried, depending on the processing conditions and the formulation composition, mannitol can crystallize in the anhydrous form, as mannitol hemihydrate (MHH; C6H14O6·0.5H2O) or as a mixture of the two. The retention of MHH in the final lyophile, and its dehydration during product storage could lead to instability of the final drug product. Our aim was to determine the influence of water vapor pressure on the kinetics of MHH dehydration and the implications on the physical stability of sucrose. Therefore, the lyophiles were exposed to a range of relative humidities (RH) and the kinetics of MHH dehydration and sucrose crystallization were monitored by X-ray diffractometry. A second set of vials (rubber stoppers fitted with humidity/temperature sensor) were stored at 40 °C, the headspace RH was continually recorded and water content was determined by Karl Fischer titrimetry. The dehydration rate of MHH increased as a function of water vapor pressure, an anomalous behavior explained by the Smith-Topley effect. An increase in headspace RH and decrease in lyophile water content in sealed vials attributed to MHH dehydration, eventually triggered sucrose crystallization. There was also evidence of moisture transfer from the lyophile to the rubber stoppers.

Accuracy and consistency of electronic root canal length determination with electrically isolating rubber stoppers.

The aim of this study was to investigate the influence of an isolating silicone stopper on the measuring accuracy and display consistency of three electrometric apex locators. The length of the canal to the major foramen was determined electrometrically using an ISO size 10 file in 20 extracted teeth each with natural crowns (Group I), amalgam fillings (Group II) or base-metal crowns (Group III), The measurements were performed with isolating or conventional silicone stoppers using three different apex locators with a four-level scale consistency rating. The use of isolating stoppers resulted in a more consistent display than with conventional stoppers, independent of the presence or type of coronal restoration (P = 0.017). Across all coronal restorations, the position of the major foramen could be determined to within ± 0.5 mm without significant differences (P = 0.79) using conventional and isolating stoppers. The use of modified isolating stoppers provides a significant increase in display consistency.

Impact of extractables from rubber closures on protein stability under heat stress.

Commercially available, uncoated elastomeric closures were examined in regard to a potential contribution of extracted compounds from the rubber stoppers to protein aggregation under worst-case conditions. All rubber stoppers were confirmed to comply with Ph. Eur. quality requirements. Extraction with 2-propanol under reflux-conditions for 3 h led to closure-specific extraction profiles of the tested samples. One type of rubber stopper exhibited a considerably greater number and higher content of extractables. Four extracted compounds were identified as trialkyl benzene-1, 2, 4-tricarboxylates (trivial name: trimellitates), a substance class which is increasingly established as an alternative to phthalates. A highly concentrated aqueous solution of total extractables from this rubber stopper facilitated the formation of soluble and non-soluble high-molecular aggregates when incubated with model biopharmaceuticals (recombinant human immunoglobulin G (IgG) and recombinant erythropoietin (EPO)) under stress conditions (IgG: 60-64 °C for 130 min, EPO: 55 °C for 8 days). Furthermore, it was shown that the surfactant concentration (polysorbate 20, 0.1 m/v% vs. 1.0 m/v%) decisively influenced the formation of high-molecular aggregates. In case of EPO, the 10 fold increased concentration of surfactant was sufficient to prevent the aggregate formation completely. This study suggests the necessity of revisiting the current test system of Ph. Eur. monograph 3.2.9 for appropriate rubber stopper quality evaluation.