Jiang Peihua knows how difficult it is to persuade a child to take a sip of bitter liquid medicine.
When their children were young, they sometimes refused to take their medicines because they didn’t like the taste, and Jiang, the neurobiologist, understood that the medical issues at stake were more than just a minor inconvenience.
Swallowing tablets can be difficult for many young children and the elderly, and while liquid medicines are easier to take, some patients avoid them altogether because the taste is so unpleasant. This poses a major obstacle to health for people who need to take life-saving medications.
“My kids hated taking medicine when they were little,” he said with a laugh. “It’s evolution. It makes sense. A bitter taste is a sign that you shouldn’t eat something. But medicine is a different story.”
So Jiang and his colleagues at the Monell Chemical Senses Center in Philadelphia have been working for years on what they say is one of the most enduring challenges in medicine: finding a “bitter taste blocker” substance that would stop patients from tasting bitter flavors.
This month, Jiang and several colleagues announced a breakthrough: They’ve found a liquid nerve inhibitor that completely blocks all tastes temporarily. The center says it’s the first temporary taste blocker that works universally in humans, a game-changer in decades of research.
“We’re very excited,” said Carol Christensen, a consultant to the Monell Lab director and co-author of a paper on the compound with Jiang. Recently Published British Journal of Pharmacology.
Bitter medicine can have adverse health effects
Researchers at Monell, an independent research institute that specializes in studying taste and smell, began developing bitter taste blockers in 2016 with a grant from the Bill & Melinda Gates Foundation. The foundation was concerned that bitter tastes could discourage people in developing countries, where many must take medication regularly to treat serious chronic diseases such as HIV and tuberculosis.
90% of pediatricians in the United States responded that “taste and preferences of medicines” are the biggest barrier to purchasing medicines. Getting patients to complete their medication regimenAccording to a 2013 review of existing research on bitter medicines for children:
The paper points out that even small tablets can be difficult for young children to swallow, and people of all ages, but especially the elderly, can have problems taking pills.
And the so-called “Mary Poppins method” of adding a spoonful of sugar to medicine to make it easier to take comes with its own risks: Sweeteners added to medicines can cause tooth decay and damage tooth enamel.
For patients with severe symptoms who require long-term treatment, HIV, etc., It is dangerous to avoid bitter medicine.
“Many children, especially in developing countries, Not taking medication “And they’re dying,” said Linda Flammer, a senior research scientist at Monell and lead author of the new paper. “Just giving them a drug they can tolerate could save their lives.”
“It’s actually really great.”
Initially, the Monell researchers hoped to develop a bitter taste blocker by targeting taste receptors on the tongue that detect bitterness, but that’s more complicated than it seems.
Sweet tastes are relatively easy to block, as they only affect two taste receptors on the tongue, but at least 25 taste receptors are devoted to detecting bitter tastes, and a person’s response to bitter tastes can vary depending on their genes.
“Some people may have strong bitter taste receptor responses, while others may not respond at all,” Flammer says.
So the researchers decided to target the neural receptors that receive signals from the taste buds, Jiang said. In their work, the researchers identified clinical trials of drugs targeting the same neural receptors to treat a variety of health conditions.
While testing one of the drugs aimed at treating chronic cough, the researchers noticed a curious side effect: “People who were taking these drugs for chronic cough were saying, ‘My sense of taste has gone haywire,'” Jiang says. The researchers wondered whether the neuroinhibitors used in the drugs could be adapted to deliberately target a person’s sense of taste.
The researchers found that holding the liquid compound in the mouth for less than a minute blocked all taste for about an hour and a half, after which taste returned to normal and patients were able to go about their daily lives without a bitter taste in their mouth.
The researchers tested the drug in adults and mice and found that the inhibitor only blocks taste, but not other senses, such as temperature in the mouth or the tingling sensation felt when taking a sip of a carbonated drink.
“It’s really amazing. I’ve never seen anything like it before,” Jiang said.
Delivering treatment to patients
The researchers say bitter taste blockers have a long way to go before they can be used in medicine. In general, it can take years for scientific findings to be distributed to the general public, with further research and safety testing. But drug companies might one day deliver the drug in kid-friendly forms, like lollipops or popsicles, to help young children feel more confident about taking their medicine, Jiang said.
“We’re now just hoping that we can take this really exciting discovery and find the right partners and the next round of funding to make it happen,” said his colleague Christensen.
Jiang also hopes to continue researching other bitter taste blockers, including ones that specifically target taste buds.
“We tried to give them a toolbox to block the bitterness,” he said.
