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A Novel Nano-formulation Technology to Enhance Anti-retroviral Drug Delivery, Efficacy and Tolerance

Solid drug nanoparticle preparation combined with common oils improves bioavailability and pharmacokinetic exposure of anti-retroviral drugs

Published: 4th January 2023
A Novel Nano-formulation Technology to Enhance Anti-retroviral Drug Delivery, Efficacy and Tolerance
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Human Immunodeficiency Virus (HIV) is a major cause of both mortality and morbidity globally. Whilst the development of anti-retroviral drug regimens has thankfully resulted in a downward trend in HIV associated deaths, the number of patients living with the disease is rising steeply. The ability to suppress viral load and prevent viral rebound, and hence maintain patient health, is dependent on long term patient compliance with often complex dosing regimens. The challenge of maintaining consistent adherence to medication is exacerbated by side effects or toxicity associated with these drugs. The disproportionate prevalence of HIV in low income countries, where diseases of poverty and tropical diseases lead to frequent co-morbidities, only compounds this problem due to the added burden of non-HIV associated polypharmacy.

In order to obtain a therapeutic plasma concentrations of drugs such as protease inhibitors, they are frequently co-administered with “pharmacoenhancers” which inhibit metabolism, improving bioavailability and reducing clearance from the body. However, this is difficult to balance precisely and when combined with other drugs or dietary fluctuations frequently results in drug-drug interactions. As a result, there remains a need for innovative formulation technologies that can maintain therapeutic concentrations without recourse to pharmacoenhancers, with less frequent administration and lower overall dose.

Technology Overview

Though compositions have been discovered that improve the characteristics of water-insoluble actives, there remains a need to further improve and modify their characteristics - particularly the pharmacokinetic and bioavailability properties of the water-insoluble actives with the ultimate goal of achieving a formulation capable of being delivered as a long acting injectable.

This innovative approach involves solid drug nanoparticle preparation in combination with common oils. A solid composition comprising nanoparticles of one or more one water-insoluble anti-retroviral therapeutic and at least one oil, dispersed within a water-soluble mixture of at least one hydrophilic polymer and at least one surfactant. The inclusion of an oil acts to stabilize otherwise unstable compositions and may have further effects on the pharmacology of the composition e.g. improving oral bioavailability, transport across membranes and/or slowing the release rate.

The oil comprising the nanoparticles need only be a biocompatible oil, which can be selected from oils such as vitamin E, peanut oil, soybean oil, sesame oil, safflower oil, vegetable oil, avocado oil, rice bran oil, jojoba oil, Babassu oil, palm oil, coconut oil, castor oil, cotton seed oil, olive oil, flaxseed oil, rapeseed oil or mixtures thereof.

Whilst applicable to all classes of water-insoluble drugs, the researchers have exemplified the technology by application to a protease inhibitor (atazanavir) and a cell entry inhibitor (maraviroc).


  • Improved pharmacokinetics leading to increased exposure
  • Table 1: Pharmacokinetic parameters of atazanavir administered orally to rats at 10mg/kg
  • Table 2: Pharmacokinetic parameters of maraviroc administered orally to rats at 10 mg/kg
  • Increased bioavailability
  • Improved overall pharmacokinetic exposure
  • Potential for administration as long acting injection


The university of Liverpool is looking for a Licensee with the formulation expertise to optimise this technology to develop next generation anti-retroviral therapeutics with ability to reach therapeutic exposure without pharmacoenhancers, with improved bioavailability and ultimately suitable for administration by long acting injection.

  • Licensing
  • Development partner