Quantum Dot-Loaded Liposomes to Evaluate the Behavior of Drug Carriers after Oral Administration

We have developed submicron-sized liposomes modified with a mucoadhesive polymer to enhance peptide drug absorption after oral administration. Liposomal behavior in the gastrointestinal tract is a critical factor for effective peptide drug delivery. The purpose of this study was to prepare quantum dot- (QD-) loaded submicron-sized liposomes and examine liposomal behavior in the body after oral administration using in vivo fluorescence imaging. Two types of CdSe/CdZnS QDs with different surface properties were used: hydrophobic (unmodified) QDs and hydrophilic QDs with glutathione (GSH) surface modifications. QD- and GSH-QD-loaded liposomes were prepared by a thin film hydration method. Transmission electron microscopy revealed that QDs were embedded in the liposomal lipid bilayer. Conversely, GSH-QDs were present in the inner aqueous phase. Some of the GSH-QDs were electrostatically associated with the lipid membrane of stearylamine-bearing cationic liposomes. QD-loaded liposomes were detected in Caco-2 cells after exposure to the liposomes, and these liposomes were not toxic to the Caco-2 cells. Furthermore, we evaluated the in vivo bioadhesion and intestinal penetration of orally administered QD-loaded liposomes by observing the intestinal segment using confocal laser scanning microscopy

Water-assisted synthesis of mesoporous calcium carbonate with a controlled specific surface area and its potential to ferulic acid release

A carbonation process to control the specific surface area of mesoporous calcium carbonate and the dissolution profile of ferulic acid on mesoporous carbonate particles are presented. The effects of water content on the physicochemical properties, specific surface area, pore size, crystallinity, and morphology are evaluated. Mesoporous calcium carbonate particles are synthesised with well-controlled specific surface areas of 38.8 to 234 m2 g-1. Each of the submicron-size secondary particles consists of a primary particle of nano-size. During secondary particle formation, primary particle growth is curbed in the case with less water content. By contrast, growth is promoted via dissolution and recrystallisation in the presence of water. The release rates of ferulic acid are gradually enhanced with increasing specific surface area of the mesoporous calcium carbonate, that reflects crystallinity of ferulic acid

Appropriate selection of an aggregation inhibitor of fine particles used for inhalation prepared by emulsion solvent diffusion

<p><b>Context:</b> Dry powder inhaler (DPI) formulations have been developed to deliver large amounts of drugs to the lungs.</p> <p><b>Objective:</b> Fine particles of a poorly water-soluble drug, the model drug ONO-2921, were prepared by the emulsion solvent diffusion (ESD) method for use in a DPI.</p> <p><b>Methods:</b> The effects of additives on the fine particle formation of ONO-2921 were estimated when droplets of an ethanolic drug solution were dispersed into aqueous media containing various additives. Subsequently, the suspensions were freeze-dried to create powdered samples to estimate the inhalation properties using a twin impinger and an Andersen cascade impactor.</p> <p><b>Results:</b> This simple ESD method produced submicron-sized ONO-2921 particles (approximately 600 nm) in combination with suitable additives. In addition, the freeze-dried powder produced using additives exhibited superior <i>in vitro</i> inhalation properties. Among these methods, the freeze-dried powder produced with 0.50% weight/volume one type of polyvinyl alcohol (PVA-205) displayed the most efficient features in the fine particle fraction (FPF). These results could be explained by the stabilization of the ONO-2921 suspension by PVA-205, indicating that PVA-205 acts as an aggregation inhibitor of fine particles.</p> <p><b>Conclusions:</b> The ESD method, in combination with appropriate types and amounts of additives, may be useful for preparing a DPI suitable for delivering drugs directly to the lungs without the assistance of carrier particles.</p