ABSTRACT
Patients' genetic characteristics, age, gender, diet, and lifestyle affect the success of medical treatment. The treatment's effectiveness can be increased by using personalized medication; however, using conventional large-scale drug production methods can restrict tablet geometry and drug dosage combinations. To create these personalized drugs, 3D printing has been studied as an alternative production method. In this study, stereolithography 3D printing is used to create custom tablet geometries using a novel biocompatible photochemistry consisting of ascorbic acid (AA) encapsulated in a poly(ethylene glycol) dimethacrylate (PEGDMA)-based polymer network and polymerized using riboflavin as a photoinitiator. The printing process is customized for the chemistry and different geometries (small and large tablet, coaxial annulus, 4-circle pattern and honeycomb pattern) with surface area to volume ratios ranging from 0.6 to 1.83 are fabricated. The tablets' microstructures are examined and the cumulative release rates in gastrointestinal conditions are analyzed periodically for 6 h. After 1 h of release, honeycomb and coaxial annulus tablet gels exhibit higher release rates at approximately 80%. The experimental data is fitted to empirical release kinetic models and the Higuchi model is shown to yield the best fitting results. Overall, by using a novel biocompatible photochemistry and 3D printing we have shown that it is possible to successfully load and release ascorbic acid as a model agent, opening up a new class of manufacturing protocols to encapsulate ascorbic acid and other water-soluble vitamins as well as many different drugs for drug delivery applications.
Subject(s)
Ascorbic Acid/chemistry , Hydrogels/chemistry , Vitamins/chemistry , Delayed-Action Preparations/chemistry , Drug Liberation , Kinetics , Printing, Three-Dimensional , Proton Magnetic Resonance Spectroscopy , Stereolithography , Technology, PharmaceuticalABSTRACT
Zero- to ultralow-field (ZULF) nuclear magnetic resonance (NMR) is an emerging tool for precision chemical analysis. In this work, we study dynamic processes and investigate the influence of chemical exchange on ZULF NMR J-spectra. We develop a computational approach that allows quantitative calculation of J-spectra in the presence of chemical exchange and apply it to study aqueous solutions of [15N]ammonium (15N[Formula: see text]) as a model system. We show that pH-dependent chemical exchange substantially affects the J-spectra and, in some cases, can lead to degradation and complete disappearance of the spectral features. To demonstrate potential applications of ZULF NMR for chemistry and biomedicine, we show a ZULF NMR spectrum of [2-13C]pyruvic acid hyperpolarized via dissolution dynamic nuclear polarization (dDNP). We foresee applications of affordable and scalable ZULF NMR coupled with hyperpolarization to study chemical exchange phenomena in vivo and in situations where high-field NMR detection is not possible to implement.
ABSTRACT
Insulin entrapped alginate-gum tragacanth (ALG-GT) hydrogels at different ALG replacement ratios (100, 75, 50, 25) were prepared through an ionotropic gelation method, followed by chitosan (CH) polyelectrolyte complexation. A mild gelation process without the use of harsh chemicals was proposed to improve insulin efficiency. Retention of almost the full amount of entrapped insulin in a simulated gastric environment and sustained insulin release in simulated intestinal buffer indicated the pH sensitivity of the gels. Insulin release from hydrogels with different formulations showed significant differences ( p < 0.05). Time domain (TD) NMR relaxometry experiments also showed the differences for different formulations, and the presence of CH revealed that ALG-GT gel formulation could be used as an oral insulin carrier at optimum concentrations. The hydrogels formulated from biodegradable, biocompatible, and nontoxic natural polymers were seen as promising devices for potential oral insulin delivery.
Subject(s)
Drug Delivery Systems/methods , Insulin/administration & dosage , Insulin/chemistry , Alginates/chemistry , Drug Carriers , Drug Delivery Systems/instrumentation , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Hydrogels/chemistry , Hydrogen-Ion Concentration , Polymers/chemistry , TragacanthABSTRACT
Edible films of gum tragacanth (GT) with whey protein were fabricated to see how the incorporation of GT influenced whey protein based film properties. Whey protein isolate (WPI) was replaced with GT at different ratios as 0.5, 1, 1.5 and 2% of WPI. Optical, mechanical, permeability and microstructural properties, as well as moisture sorption and solubility behavior of films were measured. The findings indicated that combination of WPI and GT in film formulation led to less strength, more flexible, less soluble films with lower permeability to water and with higher opacity. The results suggested that the addition of GT to WPI could lead to obtain modified WPI based edible films with desirable properties.
