A Pill of Needles

by Reyna Jones

No one can honestly say that they enjoy getting a shot at the doctor’s office. Although many people receive annual shots like flu vaccinations anxiety over these injections is short-lived – they only last a few seconds and are only required once a year. However, there are some individuals, such as people with diabetes on insulin, that must take injections every day. Although most people outgrow needle phobia, what options are there for patients who need daily shots and who are apprehensive of needles and pain? In the past, there have been few alternatives for medications typically requiring injections. This is because these prescription drugs are considerably more effective as injections than many other routes of administration. For example, when patients attempt to orally take medications of the biological class (complex proteins produced by living organisms) such as insulin, they are typically ineffective because they are broken down and severely impacted by the harsh and varying pH conditions of the digestive system. However, the invention of the Microneedle Pill may be able to combat these challenging barriers.

The Microneedle Pill or mPill is not an ordinary pill. The mPill, which was developed by scientists at MIT and Massachusetts General Hospital, is literally a pill of needles. The pill is large and oblong. The inside contains a hollow reservoir for medication with tiny, radially projecting needles overlaying this hollow core. A pH-responsive coating completely covers both the reservoir and needles. This pH-sensitive cover not only enables the pill to be swallowed painlessly but also ensures the release of the medication at the proper time. When a patient takes the mPill, it begins to travel through their digestive system. When it reaches their intestines, the pH coating dissolves, exposing the needles embedded on the pill. Muscle contractions that usually move food through the digestive system then squeeze the medication reservoir, facilitating drug release through the needles into the inner wall of the intestine. The needles, still attached to the pill capsule, are then able to pass through the remainder of the patient’s digestive system and exit the body via excretion. 

Although swallowing and digesting a pill of needles might sound painful, it is actually completely painless. Needle injections with the mPill are pain-free because pain receptors are not present in the gastrointestinal (GI) tract. In contrast, a traditional subcutaneous (“under the skin”) injection punctures the skin, which can lead to redness, swelling and soreness around the site of injection. 

To verify the efficacy and safety of the Microneedle Pill, the researchers who developed the pill tested the device in pigs using the drug insulin. Interestingly, the researchers found that the mPill insulin injections were more effective than traditional subcutaneous injections, having both a decreased onset time in the GI tract and a better drop in blood glucose levels. In patients with diabetes, it is critical that blood sugar levels do not become too high. A decreased onset time allows blood glucose levels to drop to a safer value at a faster rate. To assess the safety of the mPill, the researchers then monitored the movement and progress of the pill throughout the GI tract using X-rays. They later euthanized the pigs to perform a post-mortem examination of the GI tract and did not find any indication of damage, validating the safety of the mPill.

Although the researchers found the Microneedle Pill to be effective in pigs, they are actively working to make improvements to the device. For example, researchers are trying to modify the reservoir release mechanism to incorporate extended release as opposed to the current model which releases all the medication at the same time. For individuals with diabetes, this would mean that the pill would allow insulin to be released throughout the day, controlling blood glucose levels for a longer period of time. The researchers are also attempting to make the needles out of degradable polymers and sugar to increase the safety and efficacy of the mPill. In theory, the degradable needles could break off and become implanted in the GI tract. As the needles naturally degrade, they would gradually release medication. One potential drawback of the mPill is its relatively large size. The model used in the pig experiments was two centimeters in length by one centimeter in diameter. That is quite literally a hard pill to swallow. In addition to refining the microneedle pill, it is clear that researchers must perform more experiments before testing the pill in humans. A study that follows patients over a longer period of time should be conducted to ensure that there are not long-lasting ramifications of having needles pass through the GI tract.  

The microneedle pill has the potential to revolutionize the healthcare system and pharmaceutical industry. According to Carl Schoellhammer, an MIT graduate student and inventor of the mPill, “Injections are really horrible…they’re needed to deliver a lot of drugs – really delicate drugs like insulin – but they’re very painful. They’re very invasive...[B]ecause of people’s dislike of needles, they often don’t take their medication, and this results in significant, additional cost to the healthcare system…The microneedle pill can hopefully be able to deliver these drugs without the need of an injection, and since its easier, patients will actually do it. They’ll adhere to their drug regiment and be healthier and happier.” In addition to reducing costs and substituting insulin injections, the mPill has the potential to eventually be used for other types of biological class injections like vaccines. A pain-free flu vaccine might be in your future!