Comprehensive pharmacokinetic and tissue distribution study of α,ω-dipropionic acid polyethylene glycol (PA-PEG₁₂-PA) in rats using a validated UPLC-MS/MS method

While polyethylene glycol (PEG) is an extensively utilized pharmaceutical polymer with established biocompatibility and regulatory acceptance, the in vivo pharmacokinetics of its bifunctional derivatives, such as α,ω-dipropionic acid polyethylene glycol (PA-PEG-PA), remain largely unexplored. This study presents the development and validation of a highly sensitive and selective UPLC-MS/MS method for the accurate quantification of PA-PEG 12 -PA in various biological matrices, utilizing a straightforward protein precipitation protocol. After intravenous administration in rats (10 mg/kg), PA-PEG 12 -PA demonstrated rapid clearance (t 1/2 = 3.99 ± 1.06 h). Tissue distribution analysis revealed a pronounced affinity for renal accumulation, with kidney concentrations (16473 ± 881 ng/g at 2 h) substantially surpassing those in the liver and lungs, followed by rapid depletion within 24 h. Excretion studies indicated renal clearance as the dominant pathway, with 55.93 % of the administered dose recovered unchanged in urine over 72 h, while fecal excretion was minimal (1.76 %). This work provides the first comprehensive pharmacokinetic and biodistribution profile of PA-PEG 12 -PA, underscoring its renal-driven clearance and tissue disposition. The findings offer crucial insights for the rational design of PEGylated drug delivery systems, and the robust UPLC-MS/MS assay established herein serves as a valuable tool for characterizing polymeric excipients in biological environments.