Self-Emulsifying Drug Delivery Systems Facing the bioavailability challenge in drug delivery Sven Stegemann, Hassan Benameur, Thilo Schmierer, Martin Opitz Capsugel – A Division of Pfizer, Bornem (Belgium) Corresponding author: Dr. Sven Stegemann, Capsugel – A Division of Pfizer, Rijksweg 11, 2880 Bornem (Belgium), e-mail: sven.stegemann@pfizer.com SEDDS are pre-concentrates of excipients with a drug substance that form a thermodynamically stable micro-emulsion upon contact with aqueous media. The drug substance is kept in a solubilized form, thus improving the pharmacokinetic profile of BCS Class 2 drug substances and to optimize efficacy and safety [5].
Self-microemulsion systems are developed by a rational development program taking into account the physicochemical and biopharmaceutical properties of the drug compound. Following careful selection of the right candidate, solubility screening is performed in single excipients and later on in a combination of different excipients. Phase diagrams are established for the excipient combinations in order to identify the right concentration of each component in conjunction with the drug substance. Through the use of innovative software programs (e. g. LipidexTM), the development time of SEDDS can be substantially reduced. The lead formulations are further characterized and tested in vitro before the final formulations are selected for the in vivo trials. The uniqueness of such formulation is the ability to solve not only the poor water solubility problem of API but to also enhance biopharmaceutical performance of the drug product formulation (bioavailability, food effect, transporters, and pre systemic metabolism).
The selected lead formulation needs then be converted into a solid oral dosage form. As these SEDDS are either liquid or semi solid in nature. Their preparation generally starts with a simple blending process resulting in pre-concentrates which can be filled into two piece capsules on laboratory scale equipment (e. g. CFS 1200) for the initial in vivo testing. When larger or commercial quantities are required, the well characterized formulation is filled into two-piece capsules on the standard capsule filling machines online connected with a LEMS capsule sealing machine [24]. Key words BCS Class 2 compound • Bioenhancement • Drug delivery • Lipid drug delivery systems • Self-emulsifying drug delivery systems | 
