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Surfactant Ratio-Driven Modulation of Caffeine Loading and Release in Nigella sativa Oil Nanostructured Lipid Carriers

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The delivery of hydrophilic actives such as caffeine through lipid-based topical carriers remains a challenge due to their poor affinity for lipophilic matrices and the barrier properties of the stratum corneum. This study investigated how the Tween 80/Span 20 surfactant ratio modulates interfacial organization, caffeine encapsulation, and release behavior of caffeine-loaded nanostructured lipid carriers (NLCs) formulated with Nigella sativa oil. Five NLC formulations were prepared with fixed lipid and surfactant concentrations, varying only in Tween 80/Span 20 ratio: NLC 1 (Tween 80 only), NLC 2 (Span 20 only), NLC 3 (1:2), NLC 4 (1.5:1.5), and NLC 5 (2:1). Physicochemical and functional properties were assessed, including particle size, zeta potential, entrapment efficiency, morphology, in vitro release, and occlusion factor. Intermediate surfactant ratios (1:2 and 1.5:1.5) achieved the highest entrapment efficiency (59.57 ± 5.43% and 63.22 ± 2.98%, respectively) with controlled release, suggesting interfacial structures that favor caffeine retention without excessively restricting diffusion. In contrast, Tween-rich systems showed lower entrapment efficiency and occlusion, consistent with looser, more hydrated interfaces. Zeta potential and transmission electron microscopy confirmed surfactant ratio–dependent interfacial structuring, while occlusion data suggested that intermediate surfactant ratio systems tended to form denser films, enhancing water retention. These findings demonstrated that surfactant ratio is not merely a stabilizing factor but a tunable design element governing the nanoscale organization of lipid–aqueous interfaces. By adjusting Tween 80/Span 20 ratios, formulators can balance retention, release, and occlusion, providing a rational framework for designing next-generation NLCs with improved performance and skin compatibility.

Source: ACS Omega

DOI: 10.1021/acsomega.5c07460

Authors: Nindya Indah Damayanti, Nicholas M. H. Khong, Celine Valeria Liew, Romchat Chutoprapat

Institutions: Chulalongkorn University, Monash University Malaysia

Language: English

Topic: Advancements in Transdermal Drug Delivery

Subfield: Pharmaceutical Science

Field: Pharmacology, Toxicology and Pharmaceutics

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $1,935