Phosphatidylserine Matrix Enhances Lutein/Zeaxanthin Exposure Versus Phosphatidylcholine, Liposome, and MCT Oil in Rats: A 24‑Hour Pharmacokinetic Study

Background: Lutein and zeaxanthin (LZ) support macular function, but oral absorption is limited by intestinal solubilization and uptake; phospholipid environments may improve micellization and enterocyte transport. Objective: To evaluate whether an anionic phosphatidylserine (PS) matrix enhances single-dose LZ exposure compared to phosphatidylcholine (PC), a reconstituted liposomal powder, and medium-chain triglyceride (MCT) oil in rats. Methods: Male Sprague–Dawley rats (n=6 per group) received oral gavage of dose-matched lutein (10 mg/kg) in four matrices (MCT, MCT+PC, MCT+PS, liposome); serial plasma samples (0–24 h) were analysed using validated LC–MS/MS (calibration 5–250 ng/mL). Noncompartmental pharmacokinetics were calculated; group differences in Cmax and AUC₀–t was evaluated via one-way ANOVA with Dunnett contrasts versus MCT. Results: LZ exposure followed the order PS > PC ≈ liposome > MCT. Cmax (ng/mL, mean ± SD): 52.54 ± 0.70 (MCT), 60.45 ± 1.24 (PC), 69.63 ± 0.78 (PS), 62.39 ± 1.12 (liposome). AUC₀–t (ng·h/mL): 494.51 ± 13.70 (MCT), 596.37 ± 30.29 (PC), 620.23 ± 16.41 (PS), 536.70 ± 18.42 (liposome). Dunnett vs MCT: PS p<0.001; PC and liposome p<0.01. T_max was approximately 2 hours for PS/PC versus about 3 hours for MCT/liposome; half-life was similar (~7.7–8.3 hours). Conclusions: Anionic PS oils increase LZ exposure and bioavailability more effectively than PC or liposomal powder at equal doses, without altering elimination.