Stability of Immune Globulin Intravenous, Human-stwk, 10% Liquid Following Pooling and Storage in Flexible Containers
Stacey Ness PharmD, IgCP, CSP, MSCS, AAHIVP GC Biopharma USA sness@gcbiopharmausa.com
Alan Huber BSc Pharm, PharmD, MBA GC Biopharma USA
Suzanne Strasters MSN, FNP-C, IgCN GC Biopharma USA
Nari Ji GC Biopharma Yongin-si, South
Korea JaeWoon Son, PhD. GC Biopharma Yongin-si, South Korea
Abstract
Introduction
Immune globulin intravenous, human-stwk, 10% liquid is indicated for the treatment of primary immunodeficiency disorders associated with defects in humoral immunity. Unopened immune globulin intravenous, human-stwk, 10% liquid in its original container may be stored under refrigerated conditions at (2-8°C/36-46°F) for 36 months or may be stored for 24 months at room temperature (25°C/77°F) from the date it was manufactured. However, pooling intravenous immune globulin from several vials into a single container (usually a flexible bag) under aseptic conditions prior to administration is sometimes desirable in clinical practice.
Purpose
The purpose of this study was to determine the effects of pooling immune globulin intravenous, human-stwk, 10% liquid in 3 types of flexible containers under aseptic conditions.
Methods
Pooling of the immune globulin intravenous, human-stwk, 10% liquid was performed aseptically in a biological safety cabinet. The product was pooled into 3 types of empty containers: a polyolefin container, an EVA 2-port container, and a 3-in-1 EVA container. The following attributes were evaluated to determine product stability and quality at days 0, 1, 7, and 14: pH, total protein composition, osmolality, molecular size distribution (IgG monomers plus dimers, IgG fragments, IgG polymers), anti-complement activity, hepatitis B antibody titer, appearance, particle matter, thrombin generation activity, endotoxin, and sterility.
Conclusion
Pooled immune globulin intravenous, human-stwk, 10% liquid remained within release specifications (which are the FDA-approved requirements for immune globulin intravenous, human-stwk, 10% liquid) for all parameters evaluated for up to 14 days when stored under refrigerated conditions (2-8°C/36-46°F) in 3 commercially available flexible containers.
Key Words
Immunoglobulin, IVIG, pooling, stability, primary immunodeficiency, immune globulin.
Introduction
Primary immunodeficiency diseases (PIDs) are a large heterogenous group of disorders that result from defects in the immune system’s development and/or function and are referred to as human inborn errors of immunity (IEI).1,2 There are now 559 IEI that are known and while most are rare individually, as a group they represent a significant cause of morbidity and mortality, given that these patients can present with increased susceptibility to infectious diseases as well as autoimmune, autoinflammatory, allergic, and/or malignant diseases.2
Human immunoglobulin preparations (administered either intravenously or subcutaneously) are the cornerstone of treatment for patients with PIDs affecting the humoral immune system.3 One such product is immune globulin intravenous, humanstwk (IVIG-stwk 10%), a 10% immune globulin liquid for intravenous injection, indicated for the treatment of PIDs in adults aged 17 years and greater. This includes, but is not limited to, the humoral immune defect in congenital agammaglobulinemia, common variable immunodeficiency (CVID), X-linked agammaglobulinemia, Wiskott-Aldrich syndrome, and severe combined immunodeficiency (SCID).4
IVIG-stwk 10% is supplied in single-dose, tamperevident vials containing the labeled amount of functionally active immune globulin G (IgG). Unopened vials of IVIG-stwk 10% in its original container are to be stored under refrigerated conditions at (2-8°C/36-46°F) for 36 months or may be stored for 24 months at room temperature (25°C/77°F) from the date it was manufactured.4 Although IVIG-stwk 10% is available in 3 fill sizes, many times more than 1 vial is needed to complete a patient’s dose. Therefore, the total dose can be administered by spiking and administering 1 vial at a time, or the total dose can be pooled from the vials into a single container (usually a flexible bag) under aseptic conditions prior to administration.5 Pooling intravenous immune globulin (IVIG) can offer several benefits. It can provide streamlined administration for the administering infusion nurse, improves the patient’s ability to ambulate freely during the infusion, and provides reduced risk of container breakage during shipment and administration. However, pooling IVIG is not without disadvantages such as the risk of losing a larger amount of product if the container should break and the need to waste a greater amount of IVIG if a patient experiences an adverse event or loses IV access during the infusion. Oftentimes the benefits outweigh the risks of pooling and therefore it is common practice to pool vials of IVIG into a single container (usually a flexible bag) under aseptic conditions when desirable to do so.5,6 Although the United States Pharmacopeia (USP), a scientific nonprofit organization, sets the standard for the compounding of sterile products via the USP <797> Compounding Standards,7 it is important to understand individual product stability under these common conditions.
Stability of a pharmaceutical product is influenced by many factors such as the stability of the active ingredient; interaction between active ingredients and excipients; manufacturing process; dosage form; container system used for packaging; and exposure to light and temperature.8 Ensuring physical stability, chemical stability, and microbiological stability are of the utmost importance for patient safety.
Purpose
The purpose of this study was to determine the effects of pooling IVIG-stwk 10% in 3 types of plastic containers under aseptic conditions to determine physical, chemical, and microbiological stability for up to 14 days under refrigerated conditions.
Materials and Methods
Pooling of IVIG-stwk 10% was performed aseptically in a biological safety cabinet (BSC) within a quality control laboratory of a Good Manufacturing Practice (GMP)-certified facility. The product (ALYGLO
, GC Biopharma, IVIG-stwk 10%) was pooled by GMPtrained researchers into 1,000 mL empty polyolefin containers (IntraVia Containers, Baxter), ethyl vinyl acetate (EVA) 2-port containers (The Metrix Company), and EVA 3-in-1 containers (B. Braun) (see Table 1). For each type of bag, 2 bags were prepared for each sampling time point at day 0, 1, 7, and 14. One bag was used for sterility and visible particulate matter testing while the other bag was used for the remainder of the testing items (with the exception of day 1 as sterility testing was not performed on day 1, so the visible particulate matter testing for day 1 was performed using the pooled bag for the other testing items) (see Figure 1). Two types of bags (polyolefin and EVA 2-port) were injected with IVIG-stwk 10% using a 50 mL syringe, and the other type (EVA 3-in-1 mixing container) was able to be injected directly without any other device due to the bag design.
Pooling of IVIG-stwk 10% was performed aseptically in a biological safety cabinet (BSC) within a quality control laboratory of a Good Manufacturing Practice (GMP)-certified facility. The product (ALYGLO, GC Biopharma, IVIG-stwk 10%) was pooled by GMPtrained researchers into 1,000 mL empty polyolefin containers (IntraVia Containers, Baxter), ethyl vinyl acetate (EVA) 2-port containers (The Metrix Company), and EVA 3-in-1 containers (B. Braun) (see Table 1). For each type of bag, 2 bags were prepared for each sampling time point at day 0, 1, 7, and 14. One bag was used for sterility and visible particulate matter testing while the other bag was used for the remainder of the testing items (with the exception of day 1 as sterility testing was not performed on day 1, so the visible particulate matter testing for day 1 was performed using the pooled bag for the other testing items) (see Figure 1). Two types of bags (polyolefin and EVA 2-port) were injected with IVIG-stwk 10% using a 50 mL syringe, and the other type (EVA 3-in-1 mixing container) was able to be injected directly without any other device due to the bag design.
The volume of pooled product for each bag was 210 mL (21 grams IVIG-stwk 10%), which was chosen to maximize surface to volume ratio of the product to the container. Additionally, the volume chosen is within the FDA recommended dose for IVIG-stwk 10% for a 70kg adult.4 (70 kg x 300 mg/kg = 21,000 mg = 21 g). 210 mL from 2 x 200 mL IVIG-stwk 10% vials and 3 x 100 mL vials were pooled separately for each different container.
All pooled bags were labeled and transferred to the cold storage room (2-8°C/36-46°F) for testing on days 1, 7, and 14. The pooled bags for day 0 were evaluated directly after pooling without any storage. Samples were collected from the pooled bags for testing using an infusion set and were distributed for testing using a test tube or glass vial.
These pooled samples were compared to samples obtained from products in the original manufacturer containers, and whenever possible, the original release specifications. The following attributes were evaluated by the GMP facility’s lab to determine physical and chemical product stability and quality at days 0, 1, 7, and 14: pH, total protein composition, osmolality, molecular size distribution (IgG monomers plus dimers, IgG fragments, IgG polymers), anti-complement activity, hepatitis B antibody (Anti-HB) titer, appearance, particle matter, and thrombin generation activity (TGA). Microbiologic stability was evaluated by sterility and endotoxin testing. Sterility testing was performed on days 0, 7, and 14 and endotoxin testing was performed on days 0, 1, 7, and 14.
A brief description of selected assays used in the study are as follows. Sub-visible particle matter was measured using optical microscopy. The sample was filtered using a membrane filter (Nitrocellulose filter, 0.8 μm pore size) through a 0.22 μm filter system, and the size of the subvisible particulate matter remaining on the membrane filter was assessed by visual counts conducted by the analyst using a binocular optical microscope.9 Sterility testing was determined by filtering the sample through a membrane filter (pore size: 0.4 μm) and culturing it in Fluid Thioglycollate Medium (FTM) and Soybean Casein Digest Medium (SCDM) to check for the presence of microorganisms (bacteria or fungi).10 Endotoxin testing was conducted using an endotoxin detection reagent (LAL), and the time taken to reach a specific absorbance, as the color intensity gradually increased according to the presence of endotoxin in the sample, was measured to quantify the amount of endotoxin present in the sample.11 Anti-HBs were selected as a marker to measure antibody titers. Anti-HB titers and anticomplement activity were quantified using an automatic absorbance analyzer. Molecular size distribution (IgG monomer, dimer, polymer, aggregates, and fragments) was evaluated by size-exclusion HPLC using TSKgel G3000SW columns. The mobile phase (saline, 0.6% sodium chloride) was run isocratically at a flow rate at 0.5 mL/min and injection volume of 50 uL.12 The TGA assay was performed using a microplate reader at a temperature of 37°C, measuring the content of Factor XIa at wavelengths of 380 nm and 430 nm.13
Results
Pooled IVIG-stwk 10% remained within release specifications (which are the FDA-approved requirements for IVIG-stwk 10%) for all parameters for all pooled bags, up to 14 days when stored under refrigerated conditions (2-8°C/36-46°F). The results for the testing of the pooled product in polyolefin containers are reported in Table 2. The results for the testing of the pooled product in EVA 2-port containers are reported in Table 3. The results for the testing of the pooled product in 3-in-1 EVA containers are reported in Table 4. No assessment from any pooled sample from any of the 3 types of containers differed from product release specifications at any measured time point.
Discussion
Molecular size distribution is the most critical stability indicator for IVIG products.5 In each of the study time points for each of the containers, there was no impact of pooling on the monomer + dimer, polymer, and fragment composition. Polymers and fragments remained well below acceptance criteria at all time points while monomer + dimer distribution remained well above acceptance criteria.
Additionally, increased amounts of IgG polymers can cause non-specific complement activation, which can lead to adverse reactions in patients.5 IgG polymers were below the limits of detection in each container at each time point throughout the study. There was no increase in complement activity seen in any of the samples throughout the study.
The presence of residual activated coagulation factor XI (FXIa) has been identified as the root cause of thromboembolic events in patients who had received IVIG therapy in the past. Therefore, testing for procoagulant activity using the TGA assay is extremely important to ensure pooled IVIG-stwk 10% does not contain detectable FXIa.14 In each of the study time points for each of the containers, TGA activity remained below the limits of TGA assay detection for the TGA kit used for this testing (<1.56 mU/mL).
Storage in the flexible containers throughout the study duration did not result in any loss of protein content due to surface adsorption, despite the high surface-to-volume ratio of the product to the container, although it is important to note that transport or home storage factors were not taken into consideration in this study.
All samples taken throughout the study in each of the flexible containers confirmed microbial stability via sterility testing and the presence of endotoxin below detectable limits, which met the acceptance criteria. In this study, the pooling procedure was conducted within a BSC to minimize exposure to the external environment.
The Anti-HB titers remained stable in the pooling samples throughout the duration of the study, reflecting the absence of any potential loss in antibody titers. There are slight numerical differences in the Anti-HB potency results between container #1 and container #2 for each of the 3 container types due to differences in Anti-HB concentration in the donated plasma from which IVIG-stwk 10% is made. #1 bag contains 210 mL of pooled IVIG-stwk 10% from two 200 mL vials (Lot No. 394C23001), and #2 bag contains pooled IVIG-stwk 10% from 3 100 mL vials (Lot No. 393C23001). The Anti-HB release test result for the 200 mL vials from Lot No. 394C23001 was 79.24 IU/g, while the result for the 100 mL vials from Lot No. 393C23001 was 37.99 IU/g. Although there are differences in Anti-HB potency values between product lots, they all meet the acceptance criteria for commercial release (≥ 1.0 IU/g IgG) and did not differ significantly at any point throughout the studies for each container. As all IVIG-stwk 10% lots used in the study significantly exceeded the threshold for commercial release, the clinical significance of any variation between lots is thought to be negligible.
Conclusions
The US Pharmacopeia (USP) sets drug quality standards recognized by the FDA as the definitive source for drug safety requirements. Unless specified in the prescribing information, compounding pooled IVIG products as USP <797> Category 2 indicates that product pooling takes place in a modern clean room equipped with an ISO Class 5 Primary Engineering Control (PEC), an ISO Class 7 buffer area, and an ISO Class 8 ante-room, and the assigned beyond use date for that product may be 4 days at controlled room temperature and 10 days when refrigerated.7 In this study, pooled IVIG-stwk 10% remained within FDA-approved release specifications for all parameters evaluated for up to 14 days when stored under refrigerated conditions in 3 different commercially available containers.
Disclosures: The authors are employees of GC Biopharma USA or GC Biopharma.
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