You Shouldn’t Need a Spoonful of Sugar

Let’s be honest: the bitter taste that is present in many solid and dispersible tablets can be enough to put people off taking the drug at the required dose. There are many methods and technologies that can be used to improve the taste of medicine but, even in 2022, the patient experience often seems to come as an afterthought – and aftertaste.

For oral dosages that are soluble or require the patient to keep them in the mouth for a prolonged period, the bitterness of the API can be overwhelming (note that we are programmed as humans to be sensitive to bitter tastes as it indicates that something may be toxic).

Certain patients, especially geriatric and pediatric, often find it difficult to swallow solid tablets and capsules whole, meaning liquid and soluble formulations are a preferred delivery method. Unsurprisingly, taste for these products is key to patient compliance. We should also be aware that children are often more sensitive to bitterness than adults – and also far more likely to refuse medication! Should we care about the young and old? Well, around 34 percent of the world population is either aged under 14 or over 65 – that’s a lot of people who could benefit from drug formulations that are easy to swallow and not bitter to taste… 

You may already know that there are many ways that bitterness can be masked. The API can be coated, sweeteners or flavors can be used, resins and polymers can be added to the formulation… Each approach either overpowers the bitter flavor, reduces contact with taste buds, or delays the release of the API. With all of these options available, is it not surprising that so many formulators are still wedded to their traditional delivery formats?

So you’re sold on taste masking. What’s the best approach? Well, it really depends on the API used, the degree of bitterness, the final dosage form, manufacturing method, and the target patient population. The addition of sweeteners and flavors may not be suitable for certain patients, such as diabetics, as increased sugar intake can raise their blood sugar level, so film coating and the use of polymers and resins may be a more suitable approach. 

Ion exchange resins (IER) – insoluble polymers that contain acidic or basic functional groups – are increasingly popular but not at all new to the industry; in fact, they’ve been used for many years to control the release of APIs. By binding an ionic API to an oppositely charged polymer – the IER – to generate insoluble “resinates,” the API is not released into the mouth, and is masking its bitter taste. It later will release the API in the gastrointestinal track to produce its therapeutic effect. And as well as facilitating delayed release, they can also be used to create fast dissolving formulations, such as dispersible and orally disintegrating tablets where the API comes into direct contact with the taste receptors in the mouth but masks the bitter taste. 

I’m passionate about treating taste as an important factor in the development of new drugs – especially when so many of the world’s medicines take an oral dose form and we see a continued rise in aging populations. Do we really want higher rates of noncompliance, hindered therapeutic management, and unhappy patients? There is a clear market for liquid and soluble formulations with efficient taste masking – and it will improve patient outcomes.