Development and characterization of nano-emulsions and nano-emulgels for transdermal delivery of statins

ABSTRACT

Background

Oral administration of statins for the treatment of familial hypercholesterolemia results in poor therapeutic outcomes and patient compliance. An alternative administration route is proposed to circumvent the current limitations. This research is aimed at developing nano-emulsions and nano-emulgels as the ultimate potential delivery systems of statins for administration via the transdermal route.

Methods

Oil-in-water (o/w) nano-formulations (nano-emulsions and nano-emulgels) containing 2% (w/w) of the selected statin and 8% apricot kernel oil as oil phase were formulated. The nano-formulations were characterized using transmission electron microscopy (TEM), pH, viscosity, droplet size and zeta-potential.

Results

Nano-emulsions’ and nano-emulgels’ droplet size ranged between 114.23–169.83 nm and 149.83–267.53 nm, respectively. The addition of Carbopol® Ultrez 20 increased the nano-emulsions’ viscosity (3.59–8.38 cP) resulting in the formation of nano-emulgels (viscosity: 1911.00–46,090.00 cP). The entrapment efficiency (90.77–99.55%) confirmed the incorporation of the statins. Membrane release studies indicated that statins were released at higher flux values in nano-emulsions compared to their respective nano-emulgels. Ex vivo (skin diffusion) studies indicated higher median values in the nano-emulgels compared to their nano-emulsion counterparts.

Conclusions

The results indicate the benefits of nano-emulsions and nano-emulgels as potential alternative delivery systems for the transdermal delivery of statins.

KEYWORDS:

• Nano-emulsions
• nano-emulgels
• oil-in-water
• statins
• transdermal
• familial hypercholesterolemia

Acknowledgments

The authors would like to thank Statistical Consultation Services (Prof Faans Steyn, Dr Erika Fourie and Dr Marika Cockeran) for the statistical analysis of the studies. The authors would also like to thank Afrigen Biologics (Pty) Ltd for co-funding BLINDED Postdoctoral fellowship.

Author contributions

MN Sithole combined data, wrote and prepared the paper for publishing; S Marais performed the half of the studies and drafted the original manuscript; SM Maree performed the other half of the studies and drafted the original manuscript, while LH du Plessis, J du Plessis and M Gerber supervised the project, attained funding for the project and assisted in writing the manuscript through critical reviewing and editing. M Gerber conceptualised the research performed. All the authors contributed to the final manuscript as it was submitted to the journal and approved the submission.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.  Any opinion, findings and conclusions, or recommendations expressed in this material are those of the authors and therefore the NRF does not accept any liability in regard thereto.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The authors express gratitude to the South African National Research Foundation (NRF): Competitive Support for Unrated Researchers (CSUR) (Grant no. 105913) and the Centre of Excellence for Pharmaceutical Sciences (Pharmacen™) of the North-West University, Potchefstroom Campus, South Africa for funding these studies.