New Bill Gates-Funded Injection Could Provide Years of Birth Control in One Shot

For millions of women worldwide, birth control means daily pills, quarterly injections, or surgical procedures. But what if a single shot could eliminate all of that for years at a time? What if the solution were so simple that women could administer it themselves, anywhere in the world?

Scientists at MIT have just announced a breakthrough that could revolutionize how women access contraception. Funded by the Gates Foundation, this technology promises to deliver years of birth control through a needle so thin it barely causes pain, using an approach so elegant it almost seems like science fiction.

Behind this innovation lies a deceptively simple concept: tiny drug crystals that know precisely how to build themselves into a long-lasting medicine factory once they reach their destination under the skin. No surgery required. No daily reminders. No frequent clinic visits.

But the implications extend far beyond convenience. For the first time, women in the most remote corners of the world could have access to reliable, long-term contraception without depending on healthcare infrastructure that doesn’t exist in many places.

As researchers prepare to move this technology from laboratory animals to human trials, they’re discovering applications that could transform treatment for HIV, mental health conditions, and other diseases requiring consistent medication. Sometimes the most profound innovations come disguised as the simplest solutions.

Tiny Crystals Pack a Powerful Punch for Women’s Health

At the heart of this breakthrough lies levonorgestrel, a contraceptive hormone that MIT engineers have learned to crystallize into particles just 2-3 micrometers in diameter—smaller than the diameter of a red blood cell. When suspended in a special biocompatible liquid, these microscopic crystals can flow through needles as thin as those used for insulin injections.

What happens next borders on the miraculous. Once injected under the skin, the crystals automatically begin assembling themselves into a solid, compact depot that releases hormones gradually over months or potentially years—no external intervention required – the crystals know what to do.

“We showed that we can have very controlled, sustained delivery, likely for multiple months and even years through a small needle,” explains Giovanni Traverso, the MIT professor leading this research.

Unlike existing long-acting contraceptive implants that require surgical insertion, this system works through self-injection with a needle gauge comparable to those used by diabetics for daily insulin shots. Women could potentially administer the treatment themselves, eliminating barriers that prevent millions from accessing reliable birth control.

How Smart Crystals Build Their Birth Control Factory

Scientists refer to this technology as SLIM – Self-aggregating Long-acting Injectable Microcrystals. Behind the acronym lies sophisticated engineering that solves problems plaguing contraceptive development for decades.

Previous long-acting injectable contraceptives faced a fundamental challenge: achieving high drug concentrations while maintaining injectability through small needles. Most solutions required adding enormous amounts of polymer materials that made injections thick, painful, and challenging to administer.

MIT researchers discovered that the secret lies not in what you add, but in how crystals behave when introduced to the body’s environment. By suspending levonorgestrel crystals in benzyl benzoate, a biocompatible solvent already used in approved medications, they created a formulation that flows easily but undergoes a dramatic transformation upon injection.

“The solvent is critical because it allows you to inject the fluid through a small needle, but once in place, the crystals self-assemble into a drug depot,” Traverso notes.

When the solvent encounters body fluids, its poor mixing properties trigger crystal aggregation. The microcrystals pack together tightly, forming a solid implant that releases medication through surface erosion over extended periods.

Gates Foundation Tackles Global Contraceptive Access Crisis

This research began as part of an ambitious Gates Foundation initiative to expand contraceptive options, particularly in developing nations where healthcare infrastructure remains limited. The foundation recognized that existing solutions often fail women who need them most.

“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,” explains Vivian Feig, the study’s lead author.

Current options create impossible choices for many women. Daily pills require perfect adherence and reliable supply chains. Quarterly injections like Depo-Provera demand regular clinic visits that may be impossible for women in rural areas. Long-acting implants offer excellent protection but require the expertise of trained healthcare providers for insertion and removal.

Self-injectable, long-lasting contraception could bridge these gaps, offering implant-level effectiveness with injection-level accessibility.

Current Birth Control Options Fall Short for Many Women

Existing injectable contraceptives like Depo-Provera face significant limitations despite their popularity. While they can be administered through moderately small needles, their effectiveness lasts only three months, requiring frequent reinjections that many women struggle to maintain.

Long-acting implants, such as Nexplanon, provide 1.5 years of protection but require minor surgical procedures for insertion and removal. Many women lack access to trained providers capable of performing these procedures safely.

Between these extremes lies a vast unmet need: women seeking long-term protection without surgical intervention. Previous attempts to fill this gap have failed because of technical limitations in drug delivery systems.

Traditional long-acting injectables require polymer concentrations that make them too thick to inject through comfortable needle sizes. The only FDA-approved systems currently available require painful 18-20 gauge needles, significantly larger than what most patients can tolerate for self-injection.

MIT Team Solves the Needle Size Problem That Plagued Previous Attempts

Patient acceptance of injectable medications correlates strongly with needle size. Smaller needles cause less bruising, bleeding, and discomfort, making self-administration more practical for a broader range of people.

MIT researchers achieved what seemed impossible: cramming 293 milligrams of active drug into each milliliter of injectable solution while maintaining compatibility with 25-gauge needles or smaller. They accomplished this by eliminating the polymer excipients that typically make formulations too viscous to inject comfortably.

“By incorporating a very small amount of polymers — less than 1.6 percent by weight — we can modulate the drug release rate, extending its duration while maintaining injectability,” explains study co-author Sanghyun Park.

This represents a paradigm shift in injectable drug design. Previous systems required polymer-to-drug ratios exceeding 1:1 by weight, resulting in formulations that were too thick for comfortable injection. SLIM achieves similar performance with ratios as low as 0.0625:1, maintaining the consistency patients need for self-administration.

Revolutionary Solvent Makes the Magic Happen

Benzyl benzoate proves to be the key ingredient that enables crystal self-assembly. Already approved for human use and present in existing injectable medications, this biocompatible solvent possesses unique properties that enable SLIM technology.

Its poor miscibility with biological fluids drives the self-aggregation process. When injected, the solvent begins exchanging with surrounding tissue fluids, but does so slowly enough to allow controlled crystal packing. Different solvent exchange rates result in varying depot densities, allowing for fine-tuned control over drug release patterns.

Researchers tested multiple solvents with varying water miscibility levels, from fully miscible compounds to completely immiscible ones. Benzyl benzoate’s intermediate properties proved optimal for creating stable, long-lasting depots while maintaining injectability.

Three-Month Study Shows Promising Long-Term Potential

Initial testing in laboratory rats demonstrated the technology’s remarkable potential. Drug depots remained stable throughout the entire three-month study period, releasing medication gradually and consistently.

Most significantly, approximately 85% of the original drug remained in the depots when the study concluded, suggesting much longer release durations are possible. Researchers predict the systems could continue functioning effectively for more than a year based on this data.

“We anticipate that the depots could last for more than a year, based on our post-analysis of preclinical data. Follow-up studies are underway to further validate their efficacy beyond this initial proof-of-concept,” Park notes.

The compact nature of formed depots offers an additional safety advantage: they remain retrievable through minor surgical procedures if treatment needs to be discontinued before the drug is depleted.

Tuning the Release Rate Like a Pharmaceutical Dial

One of SLIM technology’s most impressive features is its tunability. By adding small amounts of biodegradable polymers, such as polycaprolactone, researchers can adjust release rates without compromising injectability.

These modifications work by altering depot density and porosity. Denser depots with reduced surface area release drugs more slowly, extending protection duration. Researchers can essentially dial in specific release profiles to match different contraceptive needs or therapeutic requirements.

Different women may prefer different protection durations based on their life circumstances, family planning goals, and personal preferences. SLIM technology could potentially offer options ranging from six months to several years using the same basic platform.

Beyond Birth Control: HIV and Mental Health Applications

While contraception drove initial development, researchers recognize SLIM’s potential for treating various conditions requiring consistent medication levels. HIV prevention drugs, neuropsychiatric medications, and tuberculosis treatments all face adherence challenges that long-acting formulations could address.

Mental health medications particularly benefit from steady dosing schedules that eliminate the peaks and valleys associated with daily pills. Patients struggling with depression or other psychiatric conditions often discontinue treatment during feeling-better periods, leading to relapses that could be prevented through consistent drug delivery.

HIV prevention represents another promising application. Pre-exposure prophylaxis (PrEP) requires daily medication adherence that many at-risk individuals struggle to maintain. Long-acting alternatives could dramatically improve protection rates in vulnerable populations.

From Lab Bench to Real-World Impact: What Comes Next

Researchers are now planning advanced preclinical studies to evaluate how SLIM technology performs in skin environments more similar to human tissue. These studies will help validate safety and effectiveness before moving to human trials.

The research team faces strategic decisions about which medical applications to pursue first. Contraception remains a priority, given the urgent global need and support from the Gates Foundation, but other therapeutic areas also offer compelling opportunities.

“This is a very simple system in that it’s basically a solvent, the drug, and then you can add a little bit of bioresorbable polymer. Now we’re considering which indications do we go after: Is it contraception? Is it others?” Traverso explains.

The technology’s relative simplicity could accelerate regulatory approval processes compared to more complex drug delivery systems. Fewer components typically mean fewer potential safety concerns and more straightforward manufacturing processes.

Game-Changer for Women in Resource-Limited Settings

SLIM technology’s most profound impact may occur in regions where women currently have the fewest contraceptive options. Self-administration capability eliminates healthcare infrastructure requirements that limit access in rural and underserved areas.

Women could receive initial training and supplies during infrequent clinic visits, then maintain protection independently for extended periods. This approach reduces costs, travel requirements, and dependence on healthcare systems that may be unreliable or inaccessible.

Such autonomy represents more than convenience – it provides reproductive control that can be transformative for women’s educational, economic, and social opportunities.

The Future of Long-Acting Medicine Delivery

SLIM technology represents a new paradigm in sustained drug delivery that could extend far beyond its initial applications. The platform’s minimal polymer requirements, high drug loading capacity, and patient-friendly administration distinguish it from previous approaches.

As researchers continue to develop, they’re discovering that the simplest solutions often prove to be the most revolutionary. Sometimes changing how we deliver medicine matters as much as the medicine itself.