Tunable high-Q resonator by general impedance converter.

A tunable high-Q resonator is performed in the schematics of the General Impedance Converter (GIC). In the framework of frequency dependent open-loop gain of operational amplifiers, a general formula of the frequency dependence of the impedance of GIC is derived. The explicit formulas for the resonance frequency and Q-factor include as an immanent parameter the crossover frequency of the operational amplifier.

Design and biological response of doxycycline loaded chitosan microparticles for periodontal disease treatment.

The aim of this study was to develop chitosan (CS) microparticulated mucoadhesive drug delivery system (DDS) with improved therapeutic performance and biological responce. Ionotropic gelation/spray drying process was used for preparation of doxycycline hyclate (DOXY) loaded low and medium molecular weight (LMw and MMw) CS/sodium tripolyphosphate microparticles (CS/TPP MPs), further coated with ethyl cellulose (EC) using coacervation/solvent displacement technique. The relevant physico-chemical and biopharmaceutical properties were optimized using experimental design approach.

SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation, optimization and efficacy evaluation.

One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers.

Work of adhesion between mucin macromolecule and calcium-alginate gels on molecular level.

The bioadhesion of biopolymers to mucus layers is of great interest for the development of drug delivery systems. Herein we use AFM force measurements to evaluate the interaction on molecular level between a mucin macromolecule attached to an AFM tip and a calcium-alginate gel layer. The total work of adhesion is measured from the AFM force curves depending on different parameters: time of contact, G/M ratio of the alginate, and crosslink ratio of the gel.