Nanoencapsulation of ascorbic acid loaded in pluronic® F127 coated by chitosan-alginate polyelectrolyte complex and application of a direct quantification method to enhance its accuracy.

Summary

This study develops PLX micelles coated with a chitosan–alginate polyelectrolyte complex to nanoencapsulate ascorbic acid and introduces a direct colorimetric method to quantify AA inside nanoparticles and during release. The platform yields stable, ~300–400 nm particles with favorable zeta potential and provides constant-rate AA release at pH 5.5 and 7.4, enabling more accurate formulation development for topical use.

Key Findings

• Developed PLX/CS-ALG composite nanoparticles (291–399 nm, zeta >34 mV, PDI <0.32) that stably encapsulate ascorbic acid.
• Introduced a direct colorimetric method to quantify AA inside nanoparticles and in release studies, correcting errors from degradation with indirect methods.
• Achieved constant-rate AA release at pH 5.5 and 7.4, suitable for short-term topical delivery.

Clinical Implications

For dermatology and cosmetic formulation teams, adopting direct AA quantification can prevent overestimation of loading and ensure consistent dosing in topical vitamin C products, supporting better stability claims and patient outcomes.

Limitations

• No in vivo skin permeation or clinical efficacy data.
• Short-term stability and limited assessment of long-term storage or real-world formulation matrices.

Future Directions

Integrate the direct quantification method into regulatory-quality validation, test long-term stability in finished formulations, and evaluate dermal penetration and clinical efficacy in human studies.