Semi-mechanistic PK model accurately predicts oral semaglutide steady-state pharmacokinetics, integrating SNAC's absorption impact.

Oral peptide delivery faces significant challenges due to large molecular structures, leading to poor absorption and low bioavailability. Semaglutide, a GLP-1 analogue, typically has oral bioavailability between 0.4% and 1% in the fasting state. To overcome this, sodium N-[8-{2-hydroxybenzoyl} amino] caprylate (SNAC) is employed as a permeation enhancer, specifically improving gastric permeability. Understanding the precise pharmacokinetic (PK) profile of oral semaglutide, particularly at steady-state, is crucial for optimizing dosing and formulation development, addressing a key gap in current knowledge.

Researchers developed a semi-mechanistic pharmacokinetic (PK) model to predict the steady-state PK of oral semaglutide. This model was primarily constructed using published clinical data and literature-derived parameters. The study specifically investigated the impact of SNAC concentration on the gastric absorption of semaglutide at different single doses. The model incorporated factors such as dose, SNAC concentration, gastrointestinal permeability, and intestinal first-pass effect. The single-dose oral PK model was subsequently validated using steady-state PK studies, ensuring its predictive accuracy across various dosing regimens, including intravenous (IV), single-dose, and multiple-dose oral administrations.

The developed semi-mechanistic model successfully predicted the steady-state pharmacokinetics of oral semaglutide, demonstrating robust utility for understanding its complex absorption profile. The model accurately characterized the impact of SNAC on gastric absorption, highlighting its critical role in enhancing oral bioavailability. It was validated against existing steady-state PK data, confirming its reliability across different administration routes and dosing frequencies. This comprehensive model accounts for key physiological factors, including dose, SNAC concentration, gastrointestinal permeability, and the intestinal first-pass effect, all of which significantly influence oral semaglutide PK. The successful development and validation of this model represent a significant step forward.

The developed semi-mechanistic model proved highly effective for predicting oral semaglutide pharmacokinetics, laying groundwork for advanced physiologically based pharmacokinetic (PBPK) models.