Pectin and Mucin Enhance the Bioadhesion of Drug Loaded Nanofibrillated Cellulose Films.

PURPOSE: Bioadhesion is an important property of biological membranes, that can be utilized in pharmaceutical and biomedical applications. In this study, we have fabricated mucoadhesive drug releasing films with bio-based, non-toxic and biodegradable polymers that do not require chemical modifications. METHODS: Nanofibrillar cellulose and anionic type nanofibrillar cellulose were used as film forming materials with known mucoadhesive components mucin, pectin and chitosan as functional bioadhesion enhancers. Different polymer combinations were investigated to study the adhesiveness, solid state characteristics, film morphology, swelling, mechanical properties, drug release with the model compound metronidazole and in vitro cytotoxicity using TR146 cells to model buccal epithelium. RESULTS: SEM revealed lamellar structures within the films, which had a thickness ranging 40-240 µm depending on the film polymer composition. All bioadhesive components were non-toxic and showed high adhesiveness. Rapid drug release was observed, as 60-80% of the total amount of metronidazole was released in 30 min depending on the film formulation. CONCLUSIONS: The liquid molding used was a straightforward and simple method to produce drug releasing highly mucoadhesive films, which could be utilized in treating local oral diseases, such as periodontitis. All materials used were natural biodegradable polymers from renewable sources, which are generally regarded as safe.

Monitoring the recrystallisation of amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering.

In this paper we present a fast model system for monitoring the recrystallization of quench-cooled amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering. The use of these two methods enables comparison between surface and bulk crystallization. Non-ordered mesoporous silica micro-particles were added to the system in order to alter the rate of crystallization of the amorphous xylitol. Raman measurements showed that adding silica to the system increased the rate of surface crystallization, while X-ray measurements showed that the rate of bulk crystallization decreased. Using this model system it is possible to measure fast changes, which occur in minutes or within a few hours. Raman-spectroscopy and wide-angle X-ray scattering were found to be complementary techniques when assessing surface and bulk crystallization of amorphous xylitol.

On-chip optofluidic single-particle method for rapid microscale equilibrium solubility screening of biologically active substances.

Solubility is the primary physicochemical property determining the absorption and bioavailability of substances. Here, we present an optofluidic single-particle technique for microscale equilibrium solubility determination, based on on-chip hydrodynamic particle trapping and optical particle size monitoring. The method combines the rapidity, universality, and substance sparing nature of physical analysis, with the accuracy traditionally associated with chemical analysis. Applying the diffusion layer theory, we determined the equilibrium solubility from individual pure substance microparticles of as little as 14 µg in initial mass, in a matter of seconds to minutes. The reduction in time and substance consumption, when compared to the golden standard method, is above 2 orders of magnitude. With a simultaneous improvement above 3-fold in accuracy of the solubility data, the applicability of optofluidics based analytics for small-scale high-throughput quantitative solubility and biological activity screening is demonstrated.