Protein aggregation is a major problem of therapeutic proteins because aggregation decreases their therapeutic activity, shelf life and induces immunogenicity. Stabilization against aggregation is commonly attained by addition of different excipients like sugars, surfactants, buffers, salts, amino acids, polymers etc. Generally these excipients are required in combination for stabilization. Sugars are required at a higher concentration and commonly used surfactants like polysorbates have shortcomings due to oxidative degradation. With a view to have a multi-purpose excipient to be effective at a lower concentration, we designed anti-aggregation agents (AAAs) which would encompass the functionalities of two or more conventional excipients and would curtail the number of excipients to be added for stabilization. Our first designed AAA, trehalose monooleate (TMO) is a sugar-fatty acid derivative.

It has been evaluated in-silico by docking on aggregation prone regions of model protein Bovine Serum Albumin (BSA) and experimentally its effectiveness has been validated as stabilizer against agitation and thermal stress. TMO has a lower CMC of 6mg/L, is non-hemolytic and was found to be non-toxic by sulforhodamineB (SRB) colorimetric assay in Human Hepatoma Cell Line (Hep-G2) using adriamycin as positive contol. Various spectroscopic and separation analytical techniques were employed to monitor the aggregation profile of BSA in presence and absence of TMO. CD spectroscopy showed complete retention of helical structure at concentration as low as 0.05% of TMO, while fluorescence spectroscopy provided vital insights into conformational stability rendered by TMO. Native-PAGE and SEC-HPLC studies demonstrated absence of aggregates. Molecular dynamics study on BSA-TMO docked complex further substantiated the stabilization effect. Overall, it can be said that TMO has good anti-aggregation property. The present work is a preliminary attempt towards understanding protein excipient interactions and chemistry to provide rational basis for designing a single excipient for stabilization of protein formulations.

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