Development and validation of an LC–MS/MS assay for the quantification of efavirenz in different biological matrices

Drug penetration into the CNS is an important factor influencing therapy efficacy and side effects in numerous diseases areas. This is a particularly relevant for the treatment of HIV, where the CNS represents a sanctuary site for the viral replication, as well as a potential site for toxicity [1–3]. Efavirenz is a key antiretroviral and displays many desirable PK properties, such as a long half-life allowing once daily dosing and potency against HIV [4]. Despite these favorable properties, efavirenz-containing therapy is associated with the development of CNS toxicities. There is a paucity of information describing the distribution and characterization of...