Preparation and Characterization of a Lutein Solid Dispersion to Improve Its Solubility and Stability.

Lutein has been used as a dietary supplement for the treatment of eye diseases, especially age-related macular degeneration. For oral formulations, we investigated lutein stability in artificial set-ups mimicking different physiological conditions and found that lutein was degraded over time under acidic conditions. To enhance the stability of lutein upon oral intake, we developed enteric-coated lutein solid dispersions (SD) by applying a polymer, hydroxypropyl methylcellulose acetate succinate (HPMCAS-LF), through a solvent-controlled precipitation method. The SD were characterized in crystallinity, morphology, and drug entrapment. In the dissolution profile of lutein SD, a F80 formulation showed resistance toward the acidic environment under simulated gastric conditions while exhibiting a bursting drug release under simulated intestinal conditions. Our results highlight the potential use of HPMCAS-LF as an effective matrix to enhance lutein bioavailability during oral delivery and to provide novel insights into the eye-care supplement industry, with direct benefits for the health of patients.

Preparation of Gastro-retentive Tablets Employing Controlled Superporous Networks for Improved Drug Bioavailability.

The development of an oral formulation that ensures increased bioavailability of drugs is a great challenge for pharmaceutical scientists. Among many oral formulation systems, a drug delivery system employing superporous networks was developed to provide a prolonged gastro-retention time as well as improved bioavailability of drugs with a narrow absorption window in the gastrointestinal tract. Superporous networks (SPNs) were prepared from chitosan by crosslinking with glyoxal and poly(vinyl alcohol) (PVA). The SPNs showed less porosity and decreased water uptake with an increase in the crosslinking density and content of PVA. Gastro-retentive tablets (GRTs) were formulated using hydroxypropyl methylcellulose (HPMC, a hydrophilic polymer) and the prepared SPNs. Ascorbic acid (AA), which is mainly absorbed in the proximal part of the small intestine, was selected as a model drug. The formulated GRTs exhibited no floating lag time and stayed afloat until the end of the dissolution test. The in vitro drug release from the GRTs decreased with a decrease in the water uptake of the SPNs. The profile of drug release from the GRTs corresponded to the first-order and Higuchi drug-release models. Overall, floating tablets composed of the SPNs and HPMC have potential as a favorable platform to ensure sustained release and improved bioavailability of drugs that are absorbed in the proximal part of the small intestine.

A charge-reversible nanocarrier using PEG-PLL (-g-Ce6, DMA)-PLA for photodynamic therapy.

A polyelectrolyte nanoparticle composed of PEG-PLL(-g-Ce6, DMA)-PLA was developed for nanomedicinal application in photodynamic therapy. These nanoparticles formed stable aggregates through the hydrophobic interaction of poly(lactic acid) and demonstrated pH-dependent behaviors such as surface charge conversion and enhanced cellular uptake at acidic pH, resulting in improved phototoxicity. In vivo animal imaging revealed that the prepared PEG-PLL(-g-Ce6, DMA)-PLA nanoparticles effectively accumulated at the targeted tumor site through enhanced permeability and retention effects. Reversible surface charge for PEG-PLL (-g-Ce6, DMA)-PLA nanoparticles allows the nanoparticles to escape the immune system and concentrate on the tumor tissue. Tumor growth in the nude mice treated with the nanoparticles decreased significantly and the hydrophobic interaction in the poly(lactic acid) block could allow the incorporation of multiple drugs. Therefore, the PEG-PLL(-g-Ce6, DMA)-PLA nanoparticles could have considerable potential as a nanomedicinal platform for photodynamic therapy.