Kinetic Release Data Research Articles

Chitosan Sponges with Instantaneous Shape Recovery and Multistrain Antibacterial Activity for Controlled Release of Plant-Derived Polyphenols.

Biomass-derived materials with multiple features are seldom reported so far. Herein, new chitosan (CS) sponges with complementary functions for point-of-use healthcare applications were prepared by glutaraldehyde (GA) cross-linking and tested for antibacterial activity, antioxidant properties, and controlled delivery of plant-derived polyphenols. Their structural, morphological, and mechanical properties were thoroughly assessed by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and uniaxial compression measurements, respectively. The main features of sponges were modulated by varying the CS concentration, cross-linking ratio, and gelation conditions (either cryogelation or room-temperature gelation). They exhibited complete water-triggered shape recovery after compression, remarkable antibacterial properties against Gram-positive (Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes)) and Gram-negative (Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium)) strains, as well as good radical scavenging activity. The release profile of a plant-derived polyphenol, namely curcumin (CCM), was investigated at 37 °C in simulated gastrointestinal media. It was found that CCM release was dependent on the composition and the preparation strategy of sponges. By linearly fitting the CCM kinetic release data from the CS sponges with the Korsmeyer-Peppas kinetic models, a pseudo-Fickian diffusion release mechanism was predicted.

Novel magnetic carboxymethylcellulose/chitosan bio‐nanocomposites for smart co‐delivery of sunitinib malate anticancer compound and saffron extract

AbstractPharmacological risk and economic inefficiency are some of the main shortcomings of the rapid release of drugs from nanocarriers. In the present study, relatively green, magnetic, smart dual‐carrier vehicles based on pH‐sensitive biopolymers, namely carboxymethylcellulose (CMC)/chitosan (CTS), have been developed to enable simultaneously controlled loading or releasing of sunitinib malate (STM) (anticancer) and saffron (SAF) bioactive compounds. Magnetic CMC (mCMC) was prepared by co‐precipitation of Fe2+ and Fe3+ ions and complexation process via simple electrostatic interactions between mCMC and CTS. Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy and scanning electron microscopy were used for characterization. The concentration of mCMC was found to be an important factor affecting the bio‐nanocomposite performances. In vitro release study demonstrated higher release profiles at pH = 4.5 compared to pH = 7.4. Moreover, our data showed that the release percentage of bio‐nanocomposites with a low concentration of mCMC was higher than that of bio‐nanocomposites with a higher mCMC concentration. The kinetic release data were fitted using Higuchi and Korsmeyer–Peppas models. STM‐ and SAF‐loaded mCMC/CTS demonstrated cytotoxic and antibacterial properties against MCF‐7 breast cancer cells and S. aureus bacteria, indicated by MTT assay and disk diffusion method, respectively. © 2022 Society of Industrial Chemistry.

MUCOADHESIVE BUCCAL FILMS: A NOVEL APPROACH FOR THE DELIVERY OF ANTI-HYPERTENSIVE DRUGS

The buccal drug delivery system is a prominent route of administration for drug delivery through the buccal mucosa. It is rich in blood supply with more surface area for rapid absorption as well as provides direct entry of drugs from the site of application into the systemic circulation through the jugular vein. Buccal drug delivery systems consist of various approaches such as lozenges, wafers, gels, microparticles, patches or films from which mucoadhesive buccal film is an attractive dosage form in terms of flexibility and high systemic bioavailability. Since most of the antihypertensive drugs show first-pass metabolism which leads to less oral bioavailability generally up to 20–50%. Thus, incorporation of antihypertensive drugs in mucoadhesive buccal films using mucoadhesive polymers can provide higher systemic bioavailability. The films can be formulated using various techniques such as solvent casting method and hot extrusion melt method. These films can be evaluated based on various characteristics to determine their efficacy and performance such as tensile strength, mucoadhesion residence time, and kinetic release data analysis. They have various advantages over conventional solid oral dosage forms, hence are preferable for the preparation of antihypertensive drug-loaded buccal films. Mucoadhesive buccal films of antihypertensive drugs can also provide controlled drug delivery with enhanced bioavailability.

Fe3O4-alginate nanocomposite hydrogel beads material: One-pot preparation, release kinetics and antibacterial activity

In this work, a new and easy process was developed to fabricate a Fe3O4-alginate (Fe3O4NPs-ALG) hydrogel nanocomposite magnetic beads material. This preparation way consists in crosslinking sodium alginate solution in a mixed iron chloride solution containing FeCl3 and FeCl2. All characterization techniques confirmed the formation of small Fe3O4 nanoparticles with an average size of 9 nm in the alginate biopolymer matrix, in which iron atoms were linked to carbonyl acetyl groups through a bidentate bridging coordination. Furthermore, the magnetic nanocomposite beads have negatively charged surface. The obtained material was loaded with amoxicillin (AMOX) and tested as drug delivery system in the biolysis serum (NaCl 0.9% of pH 7) and in the simulated gastric medium (pH 2.1). The results showed that a cumulative release rate of 81.49% was obtained after three days in the biolysis serum, while this release rate was about 11.65% only, after four days, in the simulated gastric medium. The kinetic release data fulfilled Korsmeyer-Peppas model and the Hixson-Crowell, respectively. Antibacterial test on drug-loaded nanocomposite beads showed high activity against three of pathogenic bacteria strains.

Formulation and Evaluation of Floating Tablets of Cefixime Trihydrate Using Chitosan

Background: Cefixime trihydrate is a third generation cephalosporin with a broad spectrum bactericidal activity. It usually requires frequent dosing due to its short biological half life, poor bioavailability, and first pass metabolism. Methods: Oral floating tablets of cefixime trihydrate was formulated using cross-linked polymers like chitosan and sodium alginate, gas generating agent sodium bicarbonate, Xanthan gum, lactose, and carbopol. The tablets were compressed by potassium bromide press and evaluated with different parameters like average weight, thickness, diameter, hardness, friability, drug content, in-vitro buoyancy study, swelling characteristics, scanning electron microscopy, and kinetic release data. Results: The formulated floating tablets showed good physiochemical properties. The kinetic profile show that the drug release follow a mixed zero order and first order kinetics and well fits with Higuchis model and followed by non-Fickian diffusion mechanism. The formulations F8 and F9 showed higher swelling index and maximum drug release compared to others. Formulations F9 was found to be stable at 45oC and 75% RH for a period of 21 days. Conclusion: From the study, it is evident that a promising gas-powered controlled release floating tablets of Cefixime can be developed to increase gastric residence time and thereby increasing its bioavailability.

Carrier systems for yerba mate extract (Ilex paraguariensis) to enrich instant soups. Release mechanisms under different pH conditions

The high antioxidant properties of yerba mate (Ilex paraguariensis) extract make it suitable as a natural food additive. Encapsulation of herbal extracts is often necessary to enhance handling and product stability. Release strategies depend on the encapsulation system and the intended use. Calcium alginate capsules, with and without a chitosan layer, containing the yerba mate extract were analyzed, in wet and dried state. Polyphenol release was quantified in gastric (HCl solution, pH = 2) and intestinal (phosphate buffer pH = 7.4) simulated fluids. Most of the encapsulated polyphenols were released in the acidic medium. However, wet capsules with chitosan maintained a higher amount of the active compound before reaching the intestinal medium. Several models were tested to fit kinetic release data; wet and dry capsules showed different release mechanisms in the acidic solution. The dry capsules hydrated, while the wet ones eroded before releasing their content mainly by diffusion. Carrier systems with yerba mate extract were added to instant vegetable soups. Capsules addition increased polyphenols content without modifying the flowability of the soups. The sensory evaluation carried out by a non-trained panel showed no significant differences between enriched and commercial soups.

Ca2+ channels and transmitter release at the active zone

Ca2+-dependent transmitter release is the most important signaling mechanism for fast information transfer between neurons. Transmitter release takes places at highly specialized active zones with sub-micrometer dimension, which contain the molecular machinery for vesicle docking and -fusion, as well as a high density of voltage-gated Ca2+ channels. In the absence of direct evidence for the ultrastructural localization of Ca2+ channels at CNS synapses, important insights into Ca2+ channel–vesicle coupling has come from functional experiments relating presynaptic Ca2+ current and transmitter release, at large and accessible synapses like the calyx of Held. First, high slope values in log–log plots of transmitter release versus presynaptic Ca2+ current indicate that multiple Ca2+ channels are involved in release control of a single vesicle. Second, release kinetics in response to step-like depolarizations revealed fast- and slowly releasable sub-pools of vesicles, FRP and SRP, which, according to the “positional” model, are distinguished by a differential proximity to Ca2+ channels. Considering recent evidence for a rapid conversion of SRP- to FRP vesicles, however, we highlight that multivesicular release events and clearance of vesicle membrane from the active zone must be taken into account when interpreting kinetic release data. We conclude that the careful kinetic analysis of transmitter release at presynaptically accessible and molecularly targeted synapses has the potential to yield important insights into the molecular physiology of transmitter release.

Gentamicin‐loaded poly(acrylic acid)‐grafted cotton fibers, part 1: Synthesis, characterization, and preliminary drug release study

AbstractThis study describes preparation of poly (acrylic acid)‐grafted cotton fibers and release of antibiotic drug gentamicin sulfate from them under physiological conditions. Poly(acrylic acid) has been grafted onto cellulose backbone of cotton fibers via Ce(IV)‐initiated polymerization in aqueous medium. The conditions obtained for optimum grafting were as follows: initiation time 30 min; initiation temperature 37°C; monomer concentration 27.8 mM; grafting temperature 30°C; nitric acid (catalyst) concentration 0.1M. The grafted fibers were characterized by FTIR, TGA, and SEM analysis. The antibiotic drug gentamicin sulfate (GS) was loaded into the grafted fibers by equilibration method and release was studied under physiological conditions. The kinetic release data was interpreted by first‐order kinetic model. Finally, drug‐loaded fibers showed fair antibacterial action against Escherichia coli. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011