[Oral emulsions: preparation and bioavailability]

Although oral L/H emulsions are rare, they constitute interesting pharmaceutical forms. Such systems are easy to administer, are good to protect a fragile lipophilic active substance and are able to modify drug release. After a recall on the principal components frequently used in these forms, such as oils surface active agents and active drugs, the mechanism of bioavailability and influencing factors are detailed. Finally, evaluation methods in order to analyse in vitro release are discussed.