Mechanistic Study of Drying Phenomena of Highly Concentrated Protein Therapeutics-Drying Kinetics and Protein Aggregation.

The fill-finish process of highly concentrated protein formulations poses several technical challenges and, in particular, the filling process is critical to ensure filling accuracy. As highly concentrated formulations comprise a significant nonvolatile fraction, drying of drug product at the filling nozzle may occur during line interruptions. In many cases, this is a result of dripping at the filling nozzle and is dependent on environmental factors. The dried product may be picked up by the units after filling interruption and, although in small quantities, the effect of drying on the quality of the drug product is currently unclear. We investigated the drying phenomenon of a highly concentrated monoclonal antibody formulation (120 mg/mL) and studied the drying kinetics and associated aggregation propensity. In this regard, we established a robust method simulating the drying process dependent on environmental conditions such as relative humidity and air flow. We revealed that the drying kinetics were characterized by an initial fast evaporation phase, which was shorter for lower relative humidity and air flow, followed by a plateau phase. Protein aggregation particularly increased during the plateau phase and was positively correlated with relative humidity. Drying kinetics and aggregate formation were modeled using Hill's equation. We highlight that drying phenomena are relevant for small-volume drug products (magnitude of 100-200 µL), in particular for dosing accuracy, but less critical for larger fill volumes in the milliliter range. Especially for the latter, they might be negligible if the dried product can fully dissolve in the first units after filling interruption and in case of consistent drug product quality because of adequate formulation choice. Ultimately, we summarize technical options to avoid drying phenomena of highly concentrated protein formulations and emphasize the importance of adequate pump parameter setting.

Prolonged In-use Stability of Reconstituted Herceptin in Commercial Intravenous Bags.

Herceptin is a humanized monoclonal antibody that selectively binds to the extracellular domain of human epidermal growth factor receptor 2 (HER2). Herceptin has an important role in the treatment of HER2-positive breast cancer when used in the neoadjuvant, adjuvant, and metastatic settings, and in the treatment of HER2-positive metastatic gastric cancer, and gastroesophageal junction adenocarcinoma. Prior to intravenous infusion, Herceptin must be reconstituted with sterile water for injection and then diluted in intravenous bags with normal saline. The objective of this study was to test the in-use physicochemical stability of the Herceptin drug product after dilution in 0.9% sodium chloride in commercial polyvinylchloride, and polyolefin/ polyethylene/polypropylene infusion bags over the course of a 7-day storage at 2°C to 8°C followed by 24 hours of storage at 30°C with ambient light exposure. Three batches of Herceptin were reconstituted to yield a 21-mg/mL solution that was stored for 48 hours at 2°C to 8°C prior to dilution with 0.9% sodium chloride to create low (0.24-mg/mL) and high (3.84-mg/mL) concentration solutions that were then tested in simulated infusions with a polyvinylchloride or polyolefin/polyethylene/polypropylene infusion bag. Samples for analysis were obtained immediately after dilution of the reconstituted solution (T0), after 7 days of storage at 5°C (T7), after 1 further day of storage at 30°C (T7+1), and after administration through intravenous tubing (Tend). Control samples were obtained from bags containing only 0.9% sodium chloride at each time point. For experiments with both infusion bags, all samples were practically free from particles, were colorless, and had low numbers of subvisible particles with no differences between control and experimental samples. No change in turbidity was detected between T0 and Tend for low and high-concentration samples for each batch. The pH values remained consistent between T0 and T7+1, and osmolality values were consistent across low-concentration and high-concentration samples. Protein content, size, and potency remained consistent throughout storage and simulated infusion. In conclusion, Herceptin remains physicochemically stable for 7 days when stored at 2°C to 8°C, followed by an additional 24 hours at 30°C when diluted in 0.9% sodium chloride and stored in commercially available polyvinylchloride or polyolefin/polyethylene/polypropylene infusion bags.

Silicone Migration From Baked-on Silicone Layers. Particle Characterization in Placebo and Protein Solutions.

A significant number of therapeutic proteins are marketed as pre-filled syringes or other drug/device combination products and have been safely used in these formats for years. Silicone oil, which is used as lubricant, can migrate into the drug product and may interact with therapeutic proteins. In this study, particles in the size range of 0.2-5 µm and ≥1 µm as determined by resonant mass measurement and micro-flow imaging/light obscuration, respectively, resulted from silicone sloughing off the container barrel after agitation. The degree of droplet formation correlated well with the applied baked-on silicone levels of 13 µg and 94 µg per cartridge. Silicone migration was comparable in placebo, 2 mg/mL and 33 mg/mL IgG1 formulations containing 0.04% (w/v) polysorbate 20. Headspace substantially increased the formation of silicone droplets during agitation. The highest particle concentrations reached, however, were still very low compared to numbers described for spray-on siliconized containers. When applying adequate baked-on silicone levels below 100 µg, bake-on siliconization efficiently limits silicone migration into the drug product without compromising device functionality.

Optimization of the bake-on siliconization of cartridges. Part II: Investigations into burn-in time and temperature.

Combination products have become popular formats for the delivery of parenteral medications. Bake-on siliconization of glass syringes or cartridges allows good piston break-loose and gliding during injection at low silicone levels. Although widely implemented in industry, still little is known and published on the effect of the bake-on process on the silicone level, layer thickness and chemical composition. In this study, cartridges were bake-on siliconized in a heat-tunnel by varying both temperature from 200 to 350°C for 12min and time from 5min to 3h at 316°C. Furthermore, a heat-oven with air-exchange was established as an experimental model. Heat treatment led to a time- and temperature-dependent decrease in the silicone level and layer thickness. After 1h at 316°C lubrication was insufficient. The silicone levels substantially decreased between 250 and 316°C after 12min. After bake-on, the peak molecular weight of the silicone remained unchanged while fractions below 5000g/mol were removed at 316 and 350°C. Cyclic low molecular weight siloxanes below 500g/mol were volatilized under all conditions. Despite most of the baked-on silicone was solvent-extractable, contact angle analysis indicated a strong binding of a remaining, thin silicone film to the glass surface.

Optimization of the bake-on siliconization of cartridges. Part I: Optimization of the spray-on parameters.

Biopharmaceutical products are increasingly commercialized as drug/device combinations to enable self-administration. Siliconization of the inner syringe/cartridge glass barrel for adequate functionality is either performed at the supplier or drug product manufacturing site. Yet, siliconization processes are often insufficiently investigated. In this study, an optimized bake-on siliconization process for cartridges using a pilot-scale siliconization unit was developed. The following process parameters were investigated: spray quantity, nozzle position, spray pressure, time for pump dosing and the silicone emulsion concentration. A spray quantity of 4mg emulsion showed best, immediate atomization into a fine spray. 16 and 29mg of emulsion, hence 4-7-times the spray volume, first generated an emulsion jet before atomization was achieved. Poor atomization of higher quantities correlated with an increased spray loss and inhomogeneous silicone distribution, e.g., due to runlets forming build-ups at the cartridge lower edge and depositing on the star wheel. A prolonged time for pump dosing of 175ms led to a more intensive, long-lasting spray compared to 60ms as anticipated from a higher air-to-liquid ratio. A higher spray pressure of 2.5bar did not improve atomization but led to an increased spray loss. At a 20mm nozzle-to-flange distance the spray cone exactly reached the cartridge flange, which was optimal for thicker silicone layers at the flange to ease piston break-loose. Initially, 10µg silicone was sufficient for adequate extrusion in filled cartridges. However, both maximum break-loose and gliding forces in filled cartridges gradually increased from 5-8N to 21-22N upon 80weeks storage at room temperature. The increase for a 30µg silicone level from 3-6N to 10-12N was moderate. Overall, the study provides a comprehensive insight into critical process parameters during the initial spray-on process and the impact of these parameters on the characteristics of the silicone layer, also in context of long-term product storage. The presented experimental toolbox may be utilized for development or evaluation of siliconization processes.

Physico-chemical Stability of MabThera Drug-product Solution for Subcutaneous Injection under in-use Conditions with Different Administration Materials.

MabThera is an essential component of the standard-of-care regimens in the treatment of non-Hodgkin lymphoma and Chronic Lymphatic Leukemia. MabThera for subcutaneous injection is a novel line extension that has been approved by the European Medicines Agency for the treatment of patients with follicular lymphoma and diffuse large B-cell lymphoma. This study aimed to evaluate in-use stability data of MabThera subcutaneous drug-product solution in single-use syringes for subcutaneous administration according to the European Medicines Agency guideline. The drug-product solution was exposed to material contact surfaces of five different administration setups commonly used in subcutaneous drug delivery. MabThera subcutaneous was transferred under aseptic conditions into polypropylene and polycarbonate syringes and stored for 1, 2, and 4 weeks at 2°C to 8°C followed by 24 hours at 30°C. After storage, subcutaneous administration was simulated and MabThera subcutaneous drug-product solution quality attributes were evaluated by using compendial physico-chemical tests, as well as suitable and validated molecule- and formulation-specific analytical methods. MabThera subcutaneous vials were treated and analyzed in parallel. The physico-chemical results of MabThera subcutaneous in the different setups were comparable to the control for all timepoints. No change in drug-product quality after storage and simulated administration was found compared to the control. However, since single-dose products do not contain preservatives, microbial contamination and growth needs to be avoided and product sterility needs to be ensured. The results showed that MabThera subcutaneous remains compatible and stable, from a physico-chemical perspective, for up to 4 weeks at 2°C to 8°C followed by 24 hours at 30°C with the contact materials tested in this study. In order to avoid and minimize microbial growth, MabThera subcutaneous should be used immediately after removal from the original packaging container and strict aseptic handling conditions need to be followed.

Analysis of thin baked-on silicone layers by FTIR and 3D-Laser Scanning Microscopy.

Pre-filled syringes (PFS) and auto-injection devices with cartridges are increasingly used for parenteral administration. To assure functionality, silicone oil is applied to the inner surface of the glass barrel. Silicone oil migration into the product can be minimized by applying a thin but sufficient layer of silicone oil emulsion followed by thermal bake-on versus spraying-on silicone oil. Silicone layers thicker than 100nm resulting from regular spray-on siliconization can be characterized using interferometric profilometers. However, the analysis of thin silicone layers generated by bake-on siliconization is more challenging. In this paper, we have evaluated Fourier transform infrared (FTIR) spectroscopy after solvent extraction and a new 3D-Laser Scanning Microscopy (3D-LSM) to overcome this challenge. A multi-step solvent extraction and subsequent FTIR spectroscopy enabled to quantify baked-on silicone levels as low as 21-325µg per 5mL cartridge. 3D-LSM was successfully established to visualize and measure baked-on silicone layers as thin as 10nm. 3D-LSM was additionally used to analyze the silicone oil distribution within cartridges at such low levels. Both methods provided new, highly valuable insights to characterize the siliconization after processing, in order to achieve functionality.