Nanoemulsions are increasingly investigated to enhance dermal drug delivery because their nanoscale droplet size can influence drug release, skin interaction and permeation. Microfluidic processing has gained attention as a route to generate nanoemulsions, offering potential for continuous, energy‑efficient manufacture, but it typically requires extensive optimisation. This study explores a pragmatic, scalable strategy: use of 3D‑printed microfluidic chips to reduce the droplet size of an initially premixed coarse emulsion to produce cationic oil‑in‑water nanoemulsions loaded with ibuprofen (2% w/w) for topical/dermal application.
The nanoemulsions investigated share the same core components: the oil phase ethyl oleate, the nonionic surfactant Tween 80, and the cationic surfactant cetyltrimethylammonium bromide. Ibuprofen was incorporated at a concentration of 2% w/w. These components were used for all preparation routes compared in the study, enabling direct comparison of size, stability and skin permeation across manufacturing methods.
Three preparation methods were assessed as benchmarks and alternatives:
The study strategy included optimisation of the formulation by PIC, preparation of premixed emulsions from that formulation (approximately 84 nm), and then application of microfluidic processing to those premixed emulsions to evaluate scalable size reduction.
Microfluidic processing was done using 3D‑printed microfluidic chips. The investigators varied microchannel geometry and flow rate to determine their effect on final nanoemulsion properties. According to the abstract, these variations did not significantly affect the resulting nanoemulsion characteristics, indicating robustness of the microchannel approach under the tested conditions.
Measured droplet sizes reported in the abstract include:
Microfluidic processing therefore achieved size reduction comparable to conventional homogenisation when applied to premixed emulsions, and PIC yielded the smallest droplets overall.
Stability assessments reported in the abstract indicate differences by preparation method:
Ex vivo skin permeation (reported amounts in the abstract) differed by preparation method:
These values indicate that while microfluidic processing improved skin delivery relative to homogenisation, PIC‑prepared nanoemulsions achieved the greatest permeation in this dataset.
Based on the abstract, microchannel processing using 3D‑printed microfluidic chips offers a scalable, continuous and energy‑efficient approach to reduce droplet size of premixed emulsions and produce cationic nanoemulsions with favorable stability and skin delivery compared with conventional homogenisation. However, PIC remained superior overall in this study in terms of smallest droplet size and highest ibuprofen skin permeation. Importantly, varying microchannel geometry and flow rate did not significantly change product properties in the tested conditions, suggesting practical robustness for scale‑up.
The PubMed abstract provides formulation composition, key particle sizes, stability time points and permeation amounts, but does not include comprehensive experimental parameters, full stability datasets, detailed microchannel geometries, flow rates, energy consumption metrics, statistical analyses, or procedural specifics. Those experimental details and full results are available in the full text of the article. The authors declared no competing interests in the conflict of interest statement.
Microfluidic reduction of premixed coarse emulsions using 3D‑printed chips produced cationic ibuprofen nanoemulsions with droplet sizes and stability comparable to conventional homogenisation and improved skin delivery relative to homogenisation, while PIC‑prepared nanoemulsions delivered the smallest droplets and the highest ibuprofen permeation in this study. Microchannel processing offers a promising, scalable continuous manufacturing option for dermal nanoemulsions, though PIC remained the most effective method for size and permeation in the reported experiments.