Innovative Drug Delivery System Stores Doses as Crystals Beneath the Skin

Many people fear injection needles, especially the large ones required for long-term medications. These drugs often need high doses delivered through thick needles because they contain polymers that form medication depots under the skin. The polymer content can range from 23% to 98% of the injection’s weight, making the process even more daunting.

To make injections less intimidating, a team of researchers from Stanford University and MIT developed a new drug delivery method that reduces the need for bulky needles. Their approach, called Self-aggregating Long-acting Injectable Microcrystals (SLIM), transforms medications into tiny crystals that self-assemble into clusters.

For their study, the team focused on levonorgestrel (LNG), a contraceptive with hydrophobic molecules capable of forming crystals. They suspended these crystals in benzyl benzoate, a solvent that mixes slowly with surrounding fluids once injected under the skin. This slow mixing allows the crystals to aggregate into a solid depot, which gradually releases the medication into the bloodstream.

Long-Lasting Drug Delivery with Minimal Polymer and Thinner Needles

This method significantly reduces the polymer content needed—less than 1.6%—while still controlling the drug’s release rate. In tests on rats over 97 days, more than 85% of the medication remained intact in the depot, suggesting this approach could allow drug delivery over six months to two years using much thinner needles.

Although this technique has so far been tested with a contraceptive, researchers believe it could be adapted for treatments like HIV and tuberculosis. Extending drug release over long periods is particularly beneficial for individuals in remote areas with limited access to healthcare.

The team published their findings in Nature Chemical Engineering and plans to move forward with preclinical studies to evaluate its effectiveness in humans. If successful, this innovation could lead to fewer and smaller needles, making long-term drug administration far less intimidating.

Read Original Article: New Atlas

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