From nanoemulsions to self-nanoemulsions, with recent advances in self-nanoemulsifying drug delivery systems (SNEDDS)

ABSTRACT

Introduction: Lipid-based drug delivery systems (LBDDS) are the most promising technique to formulate the poorly water soluble drugs. Nanotechnology strongly influences the therapeutic performance of hydrophobic drugs and has become an essential approach in drug delivery research. Self-nanoemulsifying drug delivery systems (SNEDDS) are a vital strategy that combines benefits of LBDDS and nanotechnology. SNEDDS are now preferred to improve the formulation of drugs with poor aqueous solubility.

Areas covered: The review in its first part shortly describes the LBDDS, nanoemulsions and clarifies the ambiguity between nanoemulsions and microemulsions. In the second part, the review discusses SNEDDS and elaborates on the current developments and modifications in this area without discussing their associated preparation techniques and excipient properties.

Expert opinion: SNEDDS have exhibit the potential to increase the bioavailability of poorly water soluble drugs. The stability of SNEDDS is further increased by solidification. Controlled release and supersaturation can be achieved, and are associated with increased patient compliance and improved drug loads, respectively. Presence of biodegradable ingredients and ease of large-scale manufacturing combined with a lot of ‘drug-targeting opportunities’ give SNEDDS a clear distinction and prominence over other solubility enhancement techniques.

KEYWORDS:

• Colloidal dispersions
• drug targeting
• lipid based drug delivery system (LBDDS)
• nanoemulsions
• self nanoemulsifying drug delivery system (SNEDDS)
• solubilization

Article highlights

• Nanoemulsions provide the benefits of both ‘lipid formulations’ and ‘nanotechnology’.

• Nanoemulsions and microemulsions are fundamentally different colloidal dispersions and correct distinction between them is vital as it influences the selection of fabrication and characterization methods.

• These colloidal dispersions have many structural similarities but in contrast to microemulsions, nanoemulsions are thermodynamically unstable and kinetically stable systems.

• Self nanoemulsifying drug delivery system (SNEDDS) has reinstalled the prominence of nanoemulsions by coping up the issues with nanoemulsions and lifting up the drug bioavailability profile.

• Recently researchers have revealed novel applications and types of SNEDDS like supersaturated SNEDDS, solid SNEDDS, controlled release SNEDDS, mucus permeating SNEDDS, delivery of biomolecules, double emulsions and targeted SNEDDS.

• Modern in-vitro dispersion and lipolysis tests for lipid formulations are more predictive and provide reasonable in-vitro/in-vivo correlation. HLB-RSM is a novel formulation strategy for SNEDDS and carries the potential to overcome the problems associated with old conventional formulation techniques.

This box summarizes key points contained in the article.

Acknowledgement

All authors thankfully acknowledge Higher Education Commission of Pakistan (HEC) for their support in order to complete this review.

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.

Additional information

Funding

This paper was not funded