Researchers from the Beijing University of Chemical Technology have developed a method to introduce a bubble-shaped microstructure into the base of drug-loaded dissolving microneedles for use as a transdermal drug delivery system. The team’s work was published today in Scientific Reports.
Drug-loaded dissolving microneedles are made with water soluble polymers and are designed to overcome the barrier properties of the skin for transdermal delivery. The microneedle can painlessly pierce the skin’s protective stratum corneum, creating microchannels for the therapeutic to travel through. Once the drug passes through the barrier of skin, it can diffuse into the subcutaneous tissues.
To achieve high drug delivery efficacy, the drugs need to collect at the tip of the microneedle. The team hypothesized that introducing a bubble microstructure at the tip of the needle would prevent the drug from diffusing into the body of the microneedle and enable rapid injection of the drug.
The team controlled the heights of the bubble structures, keeping them within a range of 75 micrometers to 400 micrometers. The drug-loaded microneedles with bubble structures showed reliable mechanical properties, the team reported, and were successfully inserted into pig skin. One bubble-structured microneedle delivered 80% of the loaded drug in 20 seconds, while traditional microneedles delivered 10%.