Development of a rapid sanitization solution for silica-based protein A affinity adsorbents.

Protein A chromatography media require sanitization between batches as well as prior to long-term storage. While sodium hydroxide (NaOH) is probably one of the most widely used sanitants within the bioprocess industry, it cannot be used with silica- or controlled pore glass (CPG)-based adsorbents due to the instability of the base matrix at high pH. Benzyl alcohol is commonly used for sanitizing such adsorbents, though extended contact times may be required to meet desired microbial log reduction values, especially for fungal and bacterial spore formers. With the rising market need for monoclonal antibody therapeutics, higher manufacturing throughput may be required. In such cases, a shorter sanitization cycle would be extremely beneficial to maximize manufacturing throughput and productivity. This paper describes the development of a new synergistic sanitant solution, designated PAB (120 mM phosphoric acid, 167 mM acetic acid, 2.2% benzyl alcohol) that delivers improved microbial kill kinetics, enabling sanitization times of 2-3h at room temperature, while maintaining acceptable adsorbent stability. Both the approaches taken to establish the effectiveness of the improved solution as well as confirmation of its process compatibility are covered here.

Alteplase as a catheter locking solution: in vitro evaluation of biochemical stability and antimicrobial properties.

PURPOSE: To reduce potential complications of fibrin deposition to catheter surfaces, there is increasing empiric use of alteplase as a catheter lock solution. The purpose is to evaluate the properties of alteplase when reconstituted in sterile water (SW) or bacteriostatic water (BW) for prolonged periods. MATERIALS AND METHODS: Alteplase in glass vials was reconstituted (1 mg/mL) with SW or BW (0.9% benzyl alcohol) in duplicates and stored at 37 degrees C. Biochemical assays were performed at days 0 and 7 and included optical clarity, protein concentration, percent protein monomer, and in vitro clot lysis activity. Microbiologic assays were performed on days 7 through 28 with use of a standardized antimicrobial effectiveness test (pass/fail) and pour-plate methods incubated at 22.5 degrees C (fungus, 3-7 days) or 32.5 degrees C (bacteria, 3-5 days). Organisms tested included Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Aspergillus niger. RESULTS: Biochemical assay results were as follows: on day 0, all samples were clear/colorless; protein concentrations were 1.10 mg/mL +/- 0 in SW and 1.11 mg/mL +/- 0 in BW; percent protein monomer was 8.2% +/- 0.07 in SW and 98.6% +/- 0.07 in BW; and in vitro clot lysis activity (in percent of relative activity) was 100% in all samples. On day 7, all samples were clear/colorless, protein concentrations were 1.11 mg/mL +/- 0.07 in SW and 1.11 mg/mL +/- 0.07 in BW; percent protein monomer was 97.4% +/- 0.21 in SW and 96.1% +/- 0.21 in BW; and in vitro clot lysis activity (relative activity compared with day 0) was 91% +/- 2.8 in SW and 90% +/- 2.8 in BW. Microbiologic assays (US Pharmacopeia [USP] antimicrobial effectiveness test) yielded a failing result for alteplase reconstituted in SW and a passing result for alteplase reconstituted in BW. CONCLUSIONS: Alteplase reconstituted with SW or BW remains relatively stable with retained bioactivity when stored at 37 degrees C for as long as 7 days. Despite the biochemical similarities of the two solutions, only alteplase in BW met USP criteria as an effective antimicrobial solution. Further clinical evaluation is warranted.