Development and Characterization of a Novel Dual Phytosome Loaded with Resveratrol and Syringic Acid for Parkinson’s Therapy

Abstract

Aim: The present study aimed to develop and evaluate phytosomal formulations of resveratrol, syringic acid, and
their combination to enhance bioavailability and neuroprotective efficacy through improved delivery across the
blood–brain barrier (BBB). Materials and Methods: Three phytosomal formulations of each resveratrol, syringic
acid, and their combination were prepared using different concentrations of phosphatidylcholine (0.5, 1.0, and
2.0%) and evaluated for yield, particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency
(EE). Results: All the phytosomal formulations exhibited high percentage yield (92.6–93.3%) and EE (93.3–
96%), confirming efficient complex formation of phytoconstituents with phospholipids. The average particle size
ranged from 127 to 160 nm with a PDI between 0.13 and 0.22, indicating homogenous nanoparticle dispersion.
Zeta potential values between −14.5 mV and +14.5 mV demonstrated good colloidal stability and favorable
interaction potential with the BBB. Combination phytosomes achieved EE% of R+S+PC (1:1) (96%), indicating
effective co-loading. Particle sizes varied from 215 nm (pure syringic acid) to 157.3 nm (S+PC) (1:0.5), with
PDI values of 0.16 to 0.25 indicating moderate to good uniformity, and zeta potentials between 0.3 and 14.5 mV
suggested good colloidal stability. Melting point depression in complexes confirmed Drug–Polymer interactions
and reduced crystallinity. Conclusion: The optimized phytosomal systems displayed excellent physicochemical
stability and nanoscale characteristics conducive to enhanced absorption and brain permeability. These findings
demonstrate the successful development of resveratrol–syringic acid phytosomal formulation with high EE and
good stability that significantly contributes to synergistic neuroprotective delivery in Parkinson’s therapy. Further
in vivo evaluations are necessary to validate their therapeutic efficacy and synergistic mechanisms