Applicators are crucial to microbicides’ success

Ana lives in the Dominican Republic with her two children, who she is raising alone. She suspects that her boyfriend is cheating on her, but he gives her much-needed extra money to use for food and clothes, and she feels powerless to change the relationship. She knows that his cheating places her at risk for HIV but is too afraid to ask him to use a condom. Her friends have been beaten or accused of cheating when they asked their boyfriends or husbands to wear condoms.

Economic and social factors like those Ana faces leave women and girls in developing countries powerless to protect themselves against AIDS. Microbicides, products that could reduce transmission of sexually transmitted infections, including HIV, are one solution and a focus of global attention. Several microbicides are currently in preclinical or clinical trials worldwide. They include tenofovir gel, which has shown initial success in protecting women from HIV.

When effective microbicides become available, they will offer women a new option for protecting themselves against HIV. But they will only be fully effective if they are delivered in a way that is acceptable and accessible to women. This is what drives PATH's search for microbicide delivery methods that are suitable for developing-country needs.

Asking about applicators

How much difference can an applicator really make? If the applicator causes pain or irritation, women won’t use it. If it adds too much to the cost of the microbicide, women won’t buy it. If the applicator is reusable but difficult to clean, women may reject it. At the beginning of our research, we consulted scientists, product developers, and other experts who highlighted three important issues affecting accessibility and use of microbicide products by women in the developing world: safety, cost, and acceptability. These findings have guided much of our work in microbicide delivery.

Assessing safety, cost, and acceptability

To evaluate applicator safety, PATH conducted two clinical studies comparing the safety of different applicator designs, including those that are single-use and reusable, plastic and paper, and prefilled and user-filled. 

PATH also looked at the acceptability of different applicator designs to better understand women’s perceptions and attitudes that might affect eventual use of microbicides. These studies, conducted in South Africa and the Dominican Republic, have helped inform our approach to advancing acceptable, low-cost microbicide applicators.

We have conducted numerous bench tests to evaluate dosing accuracy of applicator designs. We've also compared the effectiveness of washing methods for reusable applicators and analyzed the pricing of a variety of microbicide delivery methods.

Each of these activities has helped bring much-needed attention to the importance of applicator design to safety, cost, and acceptability of microbicide products.

The cost of microbicide delivery

Tenofovir gel, a candidate microbicide, has been demonstrated to be effective in preventing HIV transmission in a Phase 3 clinical trial. Now, researchers, policy-makers, donors, and government officials are planning for introduction in developing-country settings where women urgently need new HIV prevention options.

One challenge to their plans is the cost of the product. The microbicide gel itself is not expected to be prohibitively expensive. But the prefilled applicator used for testing in the clinical trials adds considerable cost. It's been called the most costly component of the overall microbicide product.

A simple paper applicator

We have been working with several partners, including the US Agency for International Development, CONRAD, Profamilia, and Tekpak, Inc., to evaluate a low-cost, paper applicator for microbicide delivery. Unlike the prefilled plastic applicator used in the microbicide clinical trials, women fill this applicator themselves. A mechanical "stop" in the barrel of the device tells the woman when she has inserted the right amount of gel into the applicator. This alternative applicator could not only help reduce costs for microbicide delivery, it could minimize the environmental impact of applicator disposal since disposing of paper causes less burden than disposing of plastic.

Photo: Adriane Berman.