Microscopic evaluation of pharmaceutical glass container-formulation interactions under stressed conditions

Impact of Chemical Corrosion on Mechanical Properties of Boroaluminosilicate Pharmaceutical Glasses

Boroaluminosilicate (BAS) glasses have excellent chemical durability and mechanical properties and are widely used in the pharmaceutical packaging industry. The corrosion behavior of boroaluminosilicate (BAS) glasses have been investigated for many years; however, the impact of chemical corrosion on mechanical properties of boroaluminosilicate glasses has not been well understood. In this work, the BAS glass samples were corroded in a 20 mM Glycine-NaOH buffer solution (pH = 10) at 80 °C for various durations. Within the corrosion durations, the corrosion of the glass is dominated by congruent dissolution. The results show that the elemental composition and structure of the glass surface are not altered significantly during the congruent dissolution, and the corrosion rate is mainly affected by the Si concentration in the solution. The structural change in the process of micro-crack decay is the main factor affecting the mechanical properties of the glass surface. Corrosion leads to the growth of micro-cracks and tip passivation, which causes the hardness and elastic modulus of the glass to first decrease and then increase. As corrosion proceeds, the microcracks are completely destroyed to form micropores, and the pore size and number increase with the corrosion process, resulting in the decrease in surface mechanical properties again. This work reveals the main influencing factors of congruent dissolution on mechanical properties and provides an important reference for the improvement of pharmaceutical glass strength.

Sub-Visible Particle Classification and Label Consistency Analysis for Flow-Imaging Microscopy Via Machine Learning Methods

Sub-visible particles can be a quality concern in pharmaceutical products, especially parenteral preparations. To quantify and characterize these particles, liquid samples may be passed through a flow-imaging microscopy instrument that also generates images of each detected particle. Machine learning techniques have increasingly been applied to this kind of data to detect changes in experimental conditions or classify specific types of particles, primarily focusing on silicone oil. That technique generally requires manual labeling of particle images by subject matter experts, a time-consuming and complex task. In this study, we created artificial datasets of silicone oil, protein particles, and glass particles that mimicked complex datasets of particles found in biopharmaceutical products. We used unsupervised learning techniques to effectively describe particle composition by sample. We then trained independent one-class classifiers to detect specific particle populations: silicone oil and glass particles. We also studied the consistency of the particle labels used to evaluate these models. Our results show that one-class classifiers are a reasonable choice for handling heterogeneous flow-imaging microscopy data and that unsupervised learning can aid in the labeling process. However, we found agreement among experts to be rather low, especially for smaller particles (< 8 µm for our Micro-Flow Imaging data). Given the fact that particle label confidence is not usually reported in the literature, we recommend more careful assessment of this topic in the future.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.