Accelerated shelf life modeling of appearance change in drug products using ASAP.

An accelerated stability model approach was demonstrated to accurately predict the long-term shelf life of example drug substances and drug products (indigo carmine tablets and L-ascorbic acid powder) where appearance changes were shelf life-limiting. The products were exposed outside of packaging to conditions from 50 to 90 °C and 0-80% relative humidity for up to one month to accelerate appearance changes. The appearance changes of stressed samples were quantitated using the CIELAB color scale (calculated Δ*), where a visual assessment of appearance changes likely to be noticeable was used to assign a Δ* specification limit.

Vesicle Fusion Mediated by Solanesol-Anchored DNA.

Fusion between two lipid bilayers is one of the central processes in cell biology, playing a key role in endocytosis, exocytosis, and vesicle transport. We have previously developed a model system that uses the hybridization of complementary DNA strands to model the formation of the SNARE four-helix bundle that mediates synaptic vesicle fusion and used it to study vesicle fusion to a tethered lipid bilayer. Using single vesicle assays, 70% of observed fusion events in the DNA-lipid system are arrested at the hemifusion stage, whereas only 5% eventually go to full fusion.