The long term goal of this project is to prevent mother-to-child transmission of HIV through breast feeding in resource-poor countries. We have developed a platform technology for the sustained release of a broad range of drugs by subcutaneous / intramuscular injection that can potentially provide weeks of protection from each injection. We proposed to utilize this platform to develop a sustained release depot formulation of nevirapine in order to provide prophylactic levels of nevirapine in breast-feeding HIV-negative infants of HIV-positive mothers. This treatment would involve intermittent subcutaneous dosing of the infants at intervals sufficient to increase the feasibility of the program compared to daily oral therapy.