In a bid to create a less invasive and more accessible form of birth control, scientists have created a self-injectable contraceptive shot, the components of which are able to self-assemble to form an implant. According to a new study introducing the technology, the result is a highly effective and long-term contraceptive method, which could avoid many of the trappings of traditional contraceptives.
By combining long-term drug release, as provided by contraceptive implants, with the simplified administration of injectables, the technology eliminates the need to take a pill every day and offers improved accessibility for those without easy access to medical infrastructure. What’s more, it’s delivered through a tiny needle, which would mean minimal discomfort for the patient.
“The overarching goal is to give women access to a lot of different formats for contraception that are easy to administer, compatible with being used in the developing world, and have a range of different timeframes of durations of action,” co-lead author of the study Vivian Feig said in a statement.
Traditional implants are small, flexible rods that sit under the skin and deliver contraceptive drugs over an extended period of time. Administering them requires minor surgery, limiting their accessibility. The new approach is able to get around this, using a narrow needle to deliver the contraceptive medication levonorgestrel via Self-aggregating Long-acting Injectable Microcrystals (SLIM).
Essentially, these are tiny crystals that assemble into an implant after they’ve been injected into the body. Once the implant is in place, it acts like a drug “depot”, releasing levonorgestrel as it erodes – providing protection for years, potentially.
“We showed that we can have very controlled, sustained delivery, likely for multiple months and even years through a small needle,” Giovanni Traverso, the study’s senior author, explained.
This has been a stumbling block for similar technologies: large (and therefore painful) needles have been a necessity thus far – but not for SLIM.
By using teeny crystals and a solvent (benzyl benzoate), the team has mitigated the need for bulky needles.
“Needle size and liquid viscosity are crucial considerations for commercial translation of injectables,” Traverso added in a separate statement. “Our engineering challenge was finding a way to maximize comfort for patients by using smaller needles, which cause less bruising or bleeding, and to make the viscosity low enough for easy application with the syringe by hand,”
So far, the technology has only been tested in rodents – meaning there’s likely a long way to go until it’s offered up to humans – but the researchers remain hopeful that it could become a crucial contraceptive offering in future. The next step is to conduct preclinical studies to gain a better understanding of how it may perform in the human body. Then, with any luck, it will move on to clinical trials.
“We anticipate that SLIM could be a new addition to the current suite of family planning options available to women, especially for people in low-resource settings where options for contraception and health care facilities are limited,” said Traverso.
The approach could also lend itself to other medications, potentially improving the delivery of drugs to treat HIV, tuberculosis, and neuropsychiatric conditions, according to the researchers.
The study is published in Nature Chemical Engineering.
