Altered milk protein 'potentially suitable' carrier for HIV drugs: Study

By Mark ASTLEY

- Last updated on GMT

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US researchers have devised a process they claim could lead to the development of milk-based infant formula containing anti-retroviral drugs to treat and prevent HIV in infants.

By subjecting milk to ultra-high pressure homogenization (UHPH), researchers from Penn State University and the University of Tennessee enhanced the ability of casein micelles, a protein found in cow's milk, to bind with anti-retroviral drug, Ritonavir.

Through their research, published in the Journal of Pharmaceutical Research, the US team found that during homogenization, Ritonavir interacted with milk proteins, especially casein micelles, "regardless of the processing pressure."

But when milk was homogenized at 300 MPa and 500 MPa - normal milk is processed at 10 to 15 MPa - Ritonavir "integrated to the protein matrix." 

"Skim milk powder, especially, casein micelles are potentially suitable and efficient carrier systems to develop novel milk-based and low-ethanol powder formulations of Ritonavir appropriate for pediatric applications," ​the study concluded. 

Most anti-retroviral drugs used to treat HIV and AIDS, including Ritonavir, are not well tolerated by infants, according to Federico Harte, associate professor of food science, Penn State.

“Ritonavir has a high hydrophobicity and low solubility in water, which lead to a low dissolution rate in the gastrointestinal fluid and, hence, to insufficient bioavailability,"​ he said. 

"The liquid formula used to treat infants over one month of age contains 43% ethanol and has an awful flavour that has been described as bitter-metallic, medicinal, astringent, sour and burning.”

His team's findings, however, could lead to the development of a milk-based formula that overcomes the existing solubility and administration problems.

"As a result of this enhanced binding of molecules, we believe a milk powder containing Ritonavir can be used as baby formula, providing a transport system for a drug that is not very soluble in water,"​ said Harte.

Harte and his team have since furthered their findings, and are in the "final stages"​ of an experiment in which different formulations were given to piglets.

"The hope is that - and we don't have the data yet - we find that the Ritonavir is being adequately delivered by the protein in milk,"​ Harte continued.

"So if that works, I think we are pretty close to having a formulation that can be used with hydrophobic drugs."

Source: Pharmaceutical Research 10.1007/s11095-014-1518-9
Title: Effect of Ultra-High Pressure Homogenization on the Interaction Between Bovine Casein Micelles and Ritonavir.
Authors: M Corzo-Martinez, M Mohan, J Dunlap, F Harte.

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