Researchers have developed a capsule that can deliver a week's worth of HIV drugs in a single dose an advance that could make it much easier for patients to adhere to their dosing schedule. Patients can take it just once a week and the drug will release gradually throughout the week. This type of delivery system could not only improve patients' adherence to their treatment schedule but also be used by people at risk of HIV exposure to help prevent them from becoming infected the researchers said. 'One of the main barriers to treating and preventing HIV is adherence' said Giovanni Traverso