by University of Strathclyde, Glasgow

Credit: RSC Pharmaceutics (2024). DOI: 10.1039/D3PM00074E

Researchers are attempting to improve the uptake of lifesaving HIV medication for infants and children by masking the traditionally bitter taste of the drugs.

In 2023, about 100,000 children under the age of 14 were HIV positive in sub-Saharan Africa, according to UNAIDS, the Joint United Nations Program on HIV/AIDS. While antiretroviral drugs can be used to treat the condition, it can often be challenging to convince children to take the bitter drugs.

Researchers from the University of Strathclyde in Scotland and the University of the Western Cape in South Africa have teamed up to develop a novel method to disguise the taste. The research is published in RSC Pharmaceutics.

Pediatric medicines

The standard conventional method involves adding sweeteners and flavoring agents for pediatric medicines, but this is often ineffective at masking strong bitterness and an unpleasant aftertaste can persist due to the short duration of the sweetener taste.

Instead, by using co-crystallization—where two or more different molecules are combined to create a new crystalline structure—the unpleasant taste can be reduced.

Professor Katharina Edkins from the Strathclyde Institute of Pharmacy & Biomedical Science, who researches molecular interactions in pharmaceutical materials, said, "Taste plays a significant role in the development of pharmaceutical formulations, especially for pediatric and geriatric patients, as it directly affects whether patients stick to their treatment.

"The preventative medication used for HIV tastes awful for children, and given they have to take this every day for the rest of their lives, it's vital to ensure it's something that's palatable, as if they don't take it, they will develop AIDS and die."

Professor Edkins and her team, in collaboration with the research group led by Professor Marique Aucamp at the University of the Western Cape in South Africa, focused on how the drug's bitterness could be managed using co-crystallization. This approach doesn't just rely on making the medicine sweet, but on the interaction between the drug and the additional molecule. The stronger this interaction, the more effective it is in masking the unpleasant taste.

Professor Edkins added, "The key factor isn't the actual sweetness of the ingredients, but rather the interaction between the drug and co-former in solution. The stronger that interaction, the better the bitter taste is altered."

Electrical tasting

The researchers tested this method with nevirapine (NVP), a common antiretroviral drug. After creating five different co-crystal materials of NVP, they used an electrical tasting system to assess the results. The findings showed that co-crystallization could significantly reduce the bitterness of the drug, making it much easier to take.

Professor Aucamp said, "This is a 'focus-shifter' in pharmaceutical formulation. Typically, we would add a sweetener to improve the taste of children's medication, but our study opened a whole new area for taste alteration of any medicine for any patient group."

More information: Yichun Shen et al, Exploring co-crystallisation as a technique for taste-masking of nevirapine, RSC Pharmaceutics (2024). DOI: 10.1039/D3PM00074E

Provided by University of Strathclyde, Glasgow