Development and Validation of an HPLC Method Using an Experimental Design for Analysis of Amlodipine Besylate and Enalapril Maleate in a Fixed-dose Combination

Accelerated development of a SEC-HPLC procedure for purity analysis of monoclonal antibodies using design of experiments

The complex structure of biopharmaceutical products poses an inherent need for their thorough characterization to ensure product quality, safety, and efficacy. Analytical size exclusion chromatography (SEC) is a widely used technique throughout the development and manufacturing of monoclonal antibodies (mAbs) which quantifies product size variants such as aggregates and fragments. Aggregate and fragment content are critical quality attributes (CQAs) in mAb products, as higher contents of such size heterogeneities impact product quality. Historically, SEC methods have achieved sufficient separation between the high molecular weight (HMW) species and the main product. In contrast, some low molecular weight (LMW) species are often not sufficiently different in molecular mass from the main product, making it difficult to achieve appropriate resolutions between the two species. This lack of resolution makes it difficult to consistently quantify the LMW species in mAb-based therapeutics. The following work uses a design of experiments (DoE) approach to establish a robust analytical SEC procedure by evaluating SEC column types and mobile phase compositions using two mAb products with different physiochemical properties. The resulting optimized procedure using a Waters™ BioResolve column exhibits an improved ability to resolve and quantify mAb size variants, highlighting improvement in the resolution of the LMW species. Additionally, the addition of L-arginine as a mobile phase additive showed to reduce secondary interactions and was beneficial in increasing the recoveries of the HMW species.

Pressure-sensitive multivesicular liposomes as a smart drug-delivery system for high-altitude pulmonary edema

Changes in bodily fluid pressures, such as pulmonary artery pressure, play key roles in high-altitude pulmonary edema (HAPE) and other disorders. Smart delivery systems releasing a drug in response to these pressures might facilitate early medical interventions. However, pressure-responsive delivery systems are unavailable. We here constructed hydrostatic pressure-sensitive multivesicular liposomes (PSMVLs) based on the incomplete filling of the internal vesicle space with neutral lipids. These liposomes were loaded with amlodipine besylate (AB), a next-generation calcium channel inhibitor, to treat HAPE on time. AB-loaded PSMVLs (AB-PSMVLs) were destroyed, and AB was released through treatment under hydrostatic pressure of at least 25 mmHg. At 25 mmHg, which is the minimum pulmonary artery pressure value in HAPE, 38.8% of AB was released within 1 h. In a mouse HAPE model, AB-PSMVLs concentrated in the lung and released AB to diffuse into the vascular wall. Intravenously injected AB-PSMVLs before HAPE modeling resulted in a stronger protection of lung tissues and respiratory function and lower occurrence of pulmonary edema than treatment with free drug or non-pressure-sensitive AB-loaded liposomes. This study offers a new strategy for developing smart drug delivery systems that respond to changes in bodily fluid pressures.