The overall goal of the proposed research is to design and evaluate surfaces capable of retarding cavitation in glass containers for therapeutic proteins, thereby preventing particulate formation. Therapeutic proteins are commonplace in therapy applications, but they bear an inherent risk of provoking adverse immune responses and anaphylaxis in patients. Virtually all protein drugs produce such adverse reactions in at least a fraction of patients; for some protein drugs (e.g., interferon-? for multiple sclerosis) adverse immune responses may occur in 40-60% of patients, compromising the therapeutic effect of the drug. Although there are numerous possible causes, adverse immune response and anaphylaxis reactions have been correlated with the presence of aggregated protein particulates in the 50-3000 nm range. We hypothesize that a major source of protein particulates arises from cavitation events resulting from vials being agitated, dropped, or roughly handled. Cavitation, the process by which transient gas cavities form in liquids, can result from mechanical shock or pressure fluctuations. The formation of a gas cavity is followed by a violent collapse that releases large amounts of energy and generates strong shear forces in solution. Since cavitation has been utilized to denature proteins, break and reform disulfide bonds, separate hydrogen bonding substituents, and even break covalent bonds, large macromolecules like antibodies are expected to be especially susceptible to such events. We present data supporting that even moderate shocks such as dropping vials from waist-high heights (i.e. 0.5-1.0 m) causes the formation of cavitation bubbles and protein particulates. The proposed research thus seeks to determine how surfaces affect cavitation and use this knowledge to design surfaces to either prevent cavitation and reduce particle formation. The proposed research represents a joint venture between two PIs with complementary expertise. PI Randolph is an expert on strategies to stabilize proteins against denaturation during their long journey from manufacturing to the patient, from transport to administration. In particular, he has discovered that mechanical shock on vials containing therapeutic protein formulations leads to formation of particulates, a risk factor for adverse reactions in patients. PI Goodwin will leverage his expertise utilizing surfaces engineered for maximum ultrasound contrast to determine the structure-property relationships between surface structure, roughness, and presence of surfactants on both the presence and intensity of cavitation. The research will be divided into the following specific aims:
Aim 1 : Tuning Surface Roughness and Chemical Properties through Controlled Interfacial Deposition.
Aim 2 : Establishment of Cavitation Testing Procedures on Both Flat Surfaces and Mechanical Drop Testing.
Aim 3 : Effect of Cavitation on Intravenous Immunoglobulin (IVIG) Stability.
Proteins are an important class of drugs for many diseases, but they may elicit adverse drug reactions (ADRs) that at best reduce efficacy and at worst can cause death by anaphylaxis. It has been found that many proteins that elicit ADRs have an abundance of particulates, which may be caused by cavitation (bubble formation) as a result of mechanical shock. The proposed research will determine the relationship between container (vial) surface structure, resulting cavitation, and protein particulate formation in vials subjected to mechanical shock. !