CombiCap: A novel drug formulation for the basel phenotyping cocktail.

Phenotyping of cytochrome P450 isoenzymes is used for metabolic profiling. Phenotyping cocktails are usually administered as individual marketed products, which are not designed for diagnostic applications. Therefore, a formulation strategy was developed, which can be applied to any phenotyping cocktail. The formulation was validated in vitro and in vivo in human volunteers using caffeine, efavirenz, flurbiprofen, metoprolol, midazolam, and omeprazole (Basel Cocktail). Spray dried di-calcium phosphate particles (Fujicalin) were used as an inert drug carrier for probe drugs. All drugs were successfully loaded into Fujicalin by a solvent evaporation method. Mini-tablets were produced and demonstrated good physical characteristics, expected drug content and immediate release profiles for all drug formulations. Mini-tablets were introduced into a capsule (CombiCap) and used for a pilot study in human volunteers. Plasma samples were collected and analyzed by liquid chromatography and mass spectrometry. Plasma concentration ratios between the parent drugs and the respective metabolites were equivalent for the novel CombiCap formulation and individually dosed Basel Cocktail drugs. We conclude that the CombiCap formulation platform can be easily adopted for different types of phenotyping cocktails due to its scalable and modular design, which allows a simple and convenient combination of variable doses of different probe drugs.

Polymersomes containing quantum dots for cellular imaging.

Quantum dots (QDs) are highly fluorescent and stable probes for cellular and molecular imaging. However, poor intracellular delivery, stability, and toxicity of QDs in biological compartments hamper their use in cellular imaging. To overcome these limitations, we developed a simple and effective method to load QDs into polymersomes (Ps) made of poly(dimethylsiloxane)-poly(2-methyloxazoline) (PDMS-PMOXA) diblock copolymers without compromising the characteristics of the QDs. These Ps showed no cellular toxicity and QDs were successfully incorporated into the aqueous compartment of the Ps as confirmed by transmission electron microscopy, fluorescence spectroscopy, and fluorescence correlation spectroscopy. Ps containing QDs showed colloidal stability over a period of 6 weeks if stored in phosphate-buffered saline (PBS) at physiological pH (7.4). Efficient intracellular delivery of Ps containing QDs was achieved in human liver carcinoma cells (HepG2) and was visualized by confocal laser scanning microscopy (CLSM). Ps containing QDs showed a time- and concentration-dependent uptake in HepG2 cells and exhibited better intracellular stability than liposomes. Our results suggest that Ps containing QDs can be used as nanoprobes for cellular imaging.