Gel-based drug-delivery system makes tablets a thing of the past

drug-delivery system
© iStock/Natali_Mis

Scientists have developed an innovative drug-delivery system that administers medications through gels. The new system provides an alternative method for ingesting treatments for patients who find it challenging to swallow tablets.

The new gel-based drug-delivery system is pioneered by researchers at MIT and Brigham and Women’s Hospital and has been demonstrated to administer a range of different drug types effectively. Swallowing pills or tablets can be particularly difficult and distressing for children and some adults, meaning this new gel-delivery system could revolutionise how many receive their treatments.

The novel gels are built from plant-based oils such as sesame oil and can be designed to have a range of textures, from a thickened drink to a yoghurt. The gels are stable without refrigeration, meaning they could be a promising option for getting medications to children in developing countries and adults who find swallowing pills difficult, such as older adults or those who have experienced a stroke.

Giovanni Traverso, the Karl van Tassel Career Development Assistant Professor of Mechanical Engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital, said: “This platform will change our capacity for what we can do for kids, and also for adults who have difficulty receiving medication. Given the simplicity of the system and its low cost, it could have a tremendous impact on making it easier for patients to take medications.

Designing the gel drug-delivery system

For the last decade, the team has been experimenting with novel ingestible drug-delivery systems to make medications that are traditionally administered as pills easier for children to take. There are some current strategies for this, although none of them is a perfect solution.

For example, some antibiotics and medications can be suspended in water, but that also requires a clean water supply to be available, and the drugs need to be refrigerated after being mixed. For medications that are only available in pill form, healthcare providers may dissolve them in water for children to drink, but this also relies on a clean water supply and getting the dosage right is difficult if the pills are meant for adults.

To overcome these limitations, the team aimed to create a drug-delivery system that was inexpensive, palatable, stable at extreme temperatures, and compatible with a variety of drugs. They also wanted to ensure that the drugs did not need to be mixed with water before dosing and could be delivered either orally or as a suppository.

The researchers decided to focus on oil-based gels, otherwise known as oleogels, which are predominantly utilised in the food industry to modify the texture of oily foods and raise the melting point of chocolate and ice cream.

Ameya Kirtane, a former MIT postdoc and an instructor at Brigham and Women’s Hospital, commented: “That approach gave us the capacity to deliver very hydrophobic drugs that cannot be delivered through water-based systems. It also allowed us to make these formulations with a really wide range of textures.”

The scientist experimented with a plethora of plant-derived oils, including sesame oil, cottonseed oil, and flaxseed oil, combining these with edible gelling agents such as beeswax and rice bran wax. They discovered they could achieve different textures depending on the type and concentration of oil and gelling agent, with some similar to a protein shake, whereas others were more like yoghurt or pudding.

The team collaborated with Sensory Spectrum, a consulting firm that specialises in sensory experiences, to determine the gels that were the most palatable. They ascertained that the gels that were most appealing included ones made from oils with neutral flavours, such as cottonseed oil, or those with a nutty flavour, like sesame oil.

How did the gel-delivery system perform?

The scientists tested their gels with three water-insoluble drugs included in the World Health Organization’s list of essential medicines for children: azithromycin, used to treat bacterial infections; praziquantel, used to treat parasitic infections; and lumefantrine, used to treat malaria.

Kirtane said: “Based on that list, infectious diseases really stood out in terms of what a country needs to protect its children. A lot of the work that we did in this study was focused on infectious disease medications, but from a formulation standpoint, it doesn’t matter what drug we put into these systems.”

In animal models, the researchers demonstrated that the oleogels could effectively deliver doses equal to or higher than the amounts absorbed from tablets for each drug. They also showed that an oleogel could deliver a water-soluble antibiotic called moxifloxacin hydrochloride.

Improving global access to treatment

The scientists designed the gels so that they can be stable at temperatures up to 40°C for several weeks and up to 60°C for one week, making them suitable for parts of the world that lack access to refrigeration.

Additionally, the team designed a dispenser to deliver and store the drugs that is similar to a squeezable yoghurt package, which includes compartments to separate doses. This innovation may make it easier to deliver an accurate dose for each child, depending on their weight.

The team has already obtained FDA approval to conduct a phase I clinical trial of their azithromycin oleogel, which they are aiming to initiate in the coming months.

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