Volunteer Selection and Size: The International Conference on Harmonization (ICH) guideline E11 on clinical investigation of medicinal products in the pediatric population suggests that for relative bioavailability comparison of pediatric formulations, adult subjects may be used. Therefore, the study will be performed in a minimum of 24 healthy adult subjects. However, 29 healthy adults will be enrolled to allow for two possible drop-outs and for three subjects that may develop hypersensitivity to nevirapine which is known for its hypersensitivity side effect, in form of rashes.