Opioid-based micro and nanoparticulate formulations: alternative approach on pain management

Abstract

Context Opioids have been used as the reference treatment on chronic pain. However, they are related to serious adverse effects which affect the patient compliance to treatment, as well as, his quality of life. Particulate formulations have been investigated as an alternative to improve opioid efficacy and safety. Objective Summarise the available studies concerning micro and nanoencapsulated opioid formulations discussing their biopharmaceutical characteristics, such as composition, size, in vitro release, pharmacokinetic and antinociceptive profile. Methods Papers available in 1995–2015 at Medline, Science Direct and Web of Science databases were collected and assessed. Searches were performed using varied combinations of the keywords of this work. Results Opioid-loaded particles showed prolonged drug release with maintenance of serum therapeutic concentrations and extended analgesia when compared with the free drugs. The side effects incidences were reduced or maintained the same. Conclusion Particulate formulations can significantly increase both potency and safety profiles of opioids.

Keywords:

• Opioids
• liposomes
• polymer particles
• solid lipid nanoparticles
• nanostructured lipid carriers

Acknowledgements

We would like to thank Elsevier Inc. for granting the permission to reuse the Figure 2 of this article (License No. 3782651247197), reprinted from Techniques in Regional Anesthesia and Pain Management, vol. 11, n.1, Nagle PC and Gerancher JC, DepoDur® (extended-release epidural morphine): a review of an old drug in a new vehicle, p.9-18, Copyright© (2007).

Declaration of interest

The authors declare that they have no conflict of interest.