A formulation strategy for gamma secretase inhibitor ELND006, a BCS class II compound: development of a nanosuspension formulation with improved oral bioavailability and reduced food effects in dogs.

ELND006 is a novel gamma secretase inhibitor previously under investigation for the oral treatment of Alzheimer's disease. ELND006 shows poor solubility and has moderate to high permeability, suggesting it is a Biopharmaceutics Classification System Class II compound. The poor absolute oral bioavailability of the compound in fasted dogs (F ∼11%) is attributed to poor aqueous solubility. In addition, inhibiting amyloid precursor protein but not Notch cleavage is an important goal for gamma secretase inhibitors; therefore, significant variation in bioavailability resulting from food consumption is a potential liability for this class of compounds. The objective of the present study was to determine if an ELND006 nanocrystalline formulation would offer improved and predictable pharmacokinetics. ELND006 was formulated as a nanosuspension with a mean particle size of less than 200 nm, which was stable in particle size and crystallinity for over 1 year. In addition, ELND006 nanosuspension exhibited rapid dissolution in comparison with reference active pharmaceutical ingredient (API). The in vivo performance of the ELND006 nanosuspension was tested in fed and fasted beagle dogs and compared with a gelatin capsule containing reference API. The results show that nanosizing ELND006 profoundly improved the oral bioavailability and virtually eliminated variation resulting from food intake.

Soft gelatin capsules (softgels).

It is estimated that more than 40% of new chemical entities (NCEs) coming out of the current drug discovery process have poor biopharmaceutical properties, such as low aqueous solubility and/or permeability. These suboptimal properties pose significant challenges for the oral absorption of the compounds and for the development of orally bioavailable dosage forms. Development of soft gelatin capsule (softgel) dosage form is of growing interest for the oral delivery of poorly water soluble compounds (BCS class II or class IV). The softgel dosage form offers several advantages over other oral dosage forms, such as delivering a liquid matrix designed to solubilize and improve the oral bioavailability of a poorly soluble compound as a unit dose solid dosage form, delivering low and ultra-low doses of a compound, delivering a low melting compound, and minimizing potential generation of dust during manufacturing and thereby improving the safety of production personnel. However, due to the very dynamic nature of the softgel dosage form, its development and stability during its shelf-life are fraught with several challenges. The goal of the current review is to provide an in-depth discussion on the softgel dosage form to formulation scientists who are considering developing softgels for therapeutic compounds.