Polymers are widely used in amorphous solid dispersions of poorly water-soluble drugs to provide solid-state and supersaturation stability. While low-molecular-weight hydroxypropyl cellulose polymers usually provide better formulation stability, their effect on high-drug-load formulations is still unclear. Whether spray-dried formulations which sustain supersaturated solutions in vitro can increase oral absorption in vivo also remains to be verified. Thus, we investigated the effect of the molecular weight of hydroxypropyl cellulose polymers on solid-state stability, dissolution, supersaturation stability and absorption of glibenclamide. Amorphous drug formulations were prepared by spray drying and solvent casting. Solid-state analysis was performed using polarised light microscopy (PLM), differential scanning calorimetry, and wide-angle X-ray diffraction (WAXS). Dissolution was studied in porcine bile extract-based media at fasted- and fed-state conditions. In situ rat perfusion was used to assess intestinal absorption. All formulations remained amorphous by PLM and WAXS up to 100 days under ambient storage conditions. Under accelerated stability test conditions, however, lower-molecular-weight polymers consistently provided superior stability, most likely due to improved drug–polymer mixing. Dissolution studies revealed that low-molecular-weight hydroxypropyl cellulose polymers stabilised supersaturated solutions for up to 120 min. In situ rat perfusion showed much higher intestinal absorption compared to the crystalline reference. The present study shows that lower-molecular-weight HPCs enhance the performance of high-drug-load ASDs, providing high solid-state and supersaturation stability, as well as significantly improving intestinal absorption.

Background and aims
Nanotechnology provides the opportunity for construction of modern transport devices such as nanoparticles for a variety of applications in the field of medicine. A novel experimental protocol for the formation of saponin-cholesterol-phospholipid nanoparticles of vesicular structure has been developed and applied to prepare stable nanoparticles using escin or glycyrrhizin as saponins.
Methods
The methods for nanoparticle construction include a sonication at 90 °C of the initial mixture of components, followed by an additional sonication on the next day for incorporation of an additional amount of cholesterol, thus forming stable unilamellar vesicles. Tests and assays for cell viability, erythrocyte hemolysis, flow cytometry, and fluorescent microscopy analyses have been performed.
Results
By selecting appropriate component ratios, stable and safe particles were formulated with respect to the tested bio-cells. The prepared nanoparticles have mean diameter between 70 and 130 nm, depending on their composition. The versatility of these nanoparticles allows for the encapsulation of various molecules, either within the vesicle interior for water-soluble components or within the vesicle walls for hydrophobic components. The saponin particles formed after cholesterol post-addition (E3-M2) are stable and 100 % of the cells remain viable even after 10-times dilution of the initial particle suspension. These particles are successful included into isolated mouse macrophages.
Conclusions
Among the variety of generated nanoparticles, the E3-M2 particles demonstrated properties of safe and efficient devices for future vaccine design and antigen targeting to immune system.

Amorphous solid dispersions enhance the dissolution and oral bioavailability of poorly water-soluble drugs. However, the link between polymer properties and formulation performance has not been fully clarified yet. We studied the effect of hydroxypropyl cellulose (HPC) polymers molecular weight (Mw) on the storage stability, dissolution kinetics and supersaturation stability of spray-dried amorphous glibenclamide (GLB) formulations. The solid-state stability of amorphous GLB during storage was significantly enhanced by both the 40 kDa (HPC-SSL) and 84 kDa (HPC-L) polymers, regardless of Mw differences. In contrast, HPC-SSL maintained significantly higher aqueous drug concentrations during dissolution, compared to HPC-L (its higher Mw analogue). Dedicated dissolution experiments, in situ optical microscopy and solid-state characterization revealed that aqueous drug concentrations were determined by the interplay between crystallization inhibition, drug ionization, wetting and solubilization effects: (1) HPC prevents surface nucleation, hence inhibiting crystallization, (2) intestinal colloids (bile salts and phospholipids) increase supersaturated drug concentrations via wetting and solubilization effects and (3) pH and drug ionization severely impact the degree of supersaturation. The better performance of the lower Mw HPC-SSL was due to its superior inhibition of surface crystallization during dissolution. These insights into the molecular mechanisms of dissolution and crystallization of amorphous solids provide foundation for rational formulation development.

High plasma concentrations of cholesterol are associated with cardio-vascular disease complications and high risk of myocardial infarction. The absorption of dietary cholesterol depends on its bioaccessibility, which is in turn influenced by phytosterols, saponins and lipid digestion products. Therefore, we explored the interplay between phytosterols, Quillaja Dry saponin extract (QD), their combinations and lipid digestion on cholesterol bioaccessibility via an in vitro.