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Helping the Medicine Go Down

Altered milk protein can deliver AIDS drug to infants.

The liquid formulation of Ritonavir—which is used to treat infants who have HIV/AIDS—contains 43 percent ethanol; has an awful flavor described as bitter-metallic, medicinal, astringent, sour, and burning; and causes nausea, vomiting, and diarrhea.

A new method of altering a protein in milk to bind with the antiretroviral drug Ritonavir may get around the horrible taste and awful side effects associated with the traditional formulation, according to Federico Harte, associate professor of food science.

That’s critical because an estimated 3.4 million children are living with HIV/AIDS, the World Health Organization reports, and nine out of 10 of them live in resource-limited countries in sub-Saharan Africa where effective antiretroviral treatments still are not widely accessible or available. International medical experts believe less than a third of affected children worldwide receive an antiretroviral drug.

To solve that problem, Harte looked to a group of proteins in cow’s milk called caseins. Casein proteins form spherical aggregates called casein micelles, which are responsible, incidentally, for the white color of milk. The casein micelles in mammals’ milk are natural delivery systems for amino acids and calcium from mother to young, and Harte reasoned, might deliver Ritonavir molecules as well.

He reported his research in a recent issue of the Journal of Pharmaceutical Research.

“What we found is these micelles are able to carry molecules that have very little solubility in water, that have low molecular weight, and that are very hydrophobic—such as Ritonavir. I think we are pretty close to having a formulation that can be used with hydrophobic drugs.”

—Jeff Mulhollem