Modified‐release systems have been evaluated as an option to formulations that employ the conventional delivery system and, therefore, may present side effects and reduced therapeutic efficacy. In ...general, it is more convenient to modify the release of existing drugs to overcome their drawbacks, since developing a new drug can be a quite expensive and time‐consuming process. Furosemide, a drug for hypertension treatment, when administered in the conventional form, can cause inconvenience to patients due to short and intense periods of diuresis and the need for multiple daily administrations due to its short half‐life. In order to modify its release, in the present work, furosemide was successfully incorporated into sericin/alginate matrix prepared by ionic gelation and modified by thermal or covalent cross‐linking, through the addition of proanthocyanidin, achieving high incorporations rates. This polymeric matrix provided a delayed and sustained release form for furosemide, which could improve patients' compliance to treatment and decrease its side effect. Furosemide release study demonstrated that the cross‐linking method affects the amount of dosage release and does not affect the release time, but the presence of sericin does. scanning electron microscopy, X‐ray diffraction, and FT‐IR analyses confirmed furosemide incorporation. The drug thermal stability was not affected by its incorporation and the particle size was considered suitable for multiparticulate system.
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•Sericin/alginate particles were produced for valsartan incorporation.•Evaluation of incorporation efficiency and drug loading with experimental design.•All formulations prolonged the ...valsartan release compared to the conventional form.•The sericin/alginate blend demonstrated compatibility with the drug.•Valsartan remained stable in the new pharmaceutical form.
Modifying pharmaceutical forms already available on the market is a strategy used by the pharmaceutical industries for optimizing the performance of different drugs. In the present study, a blend of sericin and alginate was proposed as a polymeric matrix for the incorporation of valsartan drug in order to prolong the release and maintain a more uniform concentration at patient’s organism, reducing the chance of side effects. A 2 full-factorial design was carried out aiming the evaluation of the variables involved and optimizing the process. The formulations that contained lower content of incorporated drug obtained less satisfactory results of incorporation efficiency, although these formulations had shown longer in vitro release profiles. Analytical characterization techniques confirmed the incorporation of the drug into the matrix and showed an increase in the thermal stability of the drug after its incorporation into the polymeric matrix. Accelerated stability study proved the stability of the pharmaceutical form after 6 months period.
Increased wastewater production in the last several years has led to interest in new wastewater treatment technologies such as adsorption. This work evaluated the removal process of Zn2+/Cu2+ binary ...solutions using expanded vermiculite as alternative adsorbent. Assays were performed in dynamic systems to evaluate the influence of operating flow rate, adsorbate initial concentration and molar fraction on the adsorption process. Expanded vermiculite presented higher selectivity for zinc in single solutions as well as in binary system.
•Copper and zinc binary adsorption in dynamic system was evaluated.•The optimum flow rate was obtained as 7mL/min.•Zinc was better removed than copper in binary dynamic system.•Vermiculite presented higher affinity and selectivity for zinc than for copper.
Several studies have been conducted to evaluate and to improve wastewater treatment. Among the contaminants in wastewater, toxic metals stand out and their removal by adsorption process is of great ...interest. Silver and copper binary adsorption on bentonite was evaluated in the present work, using a fixed bed dynamic system. Initially, a fluid dynamic study was performed with different flow rates and efficiency and mass transfer parameters were analyzed. Using the optimum flow rate, the effects of initial concentration and molar fraction were investigated according to the same parameters, besides metals removal. Next, two adsorption and desorption cycles were performed using nitric acid as eluent. Regenerated clay, after elution with nitric acid, was characterized in order to verify morphology, thermal stability, functional groups and crystal structure.
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•Copper and silver binary adsorption in fixed bed flow-through column was evaluated.•Verde-lodo clay presented higher affinity and selectivity for copper than silver.•The higher initial concentrations showed the best removal results.•Nitric acid was efficient as eluent of Ag and Cu in adsorption-desorption cycles.•No significant changes were observed in the regenerated clay characterization.
The development of new forms of drugs from the current existing active principles is an alternative to the costly and time-consuming process of developing new ones. The blend of sericin and alginate ...has been proposed as a polymer matrix for the incorporation of ketoprofen as a modified formulation. An experimental design was performed by varying the initial amount of alginate and drug added. Incorporation efficiency, drug loading, and release time of 85% were applied as response variables. Drug loading was statistically affected by both independent variables and the highest value (40.25 ± 0.23%) was achieved for the lower amount of alginate and higher amount of ketoprofen initially added. The incorporation efficiency was statistically affected only by the amount of alginate and its higher values were reached by the smaller amount of alginate added. Time to release 85% was not affected by any of the independent variables, although the longer times were achieved for the greater amount of drug added. In general, the best particle produced was K3, produced with the lowest amount of alginate and higher amount of ketoprofen initially added. The characterization analyzes of SEM, FTIR, XRD, OM and TGA confirmed the incorporation of ketoprofen.
This manuscript evaluates the development of sericin/alginate particles loaded with ketoprofen. By means of statistical design, the particles were obtained and characterized by the incorporation efficiency, in vitro dissolution, morphology, size distributions, functional groups, thermal stability, and cristallinity. The best results were obtained for the lower amount of alginate and larger amount of ketoprofen initially added. Display omitted
•Ketoprofen was incorporated into sericin/alginate blend through statistical design.•Sericin improved drug incorporation about 13.5%.•Low amount of alginate and large amount of drug provided the lowest time to release.•Drug release time of the particles was 4 times slower than immediate-release form.•The main mechanism for drug release was matrix erosion.
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•Proanthocyanidin was used as covalent crosslinking agent of sericin/alginate blend.•PA-crosslinked sericin/alginate was used as matrix for ketoprofen extended release.•The obtained ...formulations presented gastro-resistant characteristic.•The particle with the lowest amount of PA showed ketoprofen extended release.•A complex release mechanism was associated to ketoprofen release.
Sericin and alginate blend has shown good results for obtaining sustained release dosage forms. In the case of ketoprofen, it was necessary to resort to the use of the proanthocyanidin (PA) as crosslinking agent in order to achieve this same goal. Thus, various formulations were developed by adding different initial amounts of PA to the sericin and alginate blend with incorporated ketoprofen. The best results for drug loading, entrapment efficiency and release prolongation were obtained for the particle with the lowest amount of PA (0.5%). Mathematical modeling has indicated that different mechanisms may be involved in drug release, especially a complex release mechanism, with polymer dissolution and polymer chain relaxation allowing drug release. Particles characterization confirmed the incorporation of ketoprofen into the sericin, alginate and proanthocyanidin blend. It was verified that there was no interaction between them and there were no major changes in the physicochemical properties of the drug.
Sericin is a water-soluble globular protein present in the silkworm cocoons (Bombyx mori), usually discharged in the wastewater of degumming process. Sodium alginate is a natural polysaccharide ...extracted from brown seaweed that has an abundant use in drug delivery systems. The blend of sericin/alginate may provide the most suitable characteristics for improvement of the drug encapsulation. The modification of the form of drug presentation becomes desirable for improved patient compliance and decreased side effects. The objective of this work is to evaluate the incorporation efficiency of quetiapine fumarate, acetylsalicylic acid, ibuprofen and ketoprofen in sericin/alginate particles. These particles were prepared by the ionic gelation technique using a blend of sericin and sodium alginate, with the drug embedded, and then, dripping the blend in calcium solution. The efficiency of incorporation was investigated for all formulations. The two best formulations were characterized by SEM (surface morphology) and by FTIR (drug polymer interaction). The results showed that the efficiency of incorporation reached values close to 18 % for quetiapine fumarate, 32 % for acetylsalicylic acid, 77 % for ibuprofen, and 81 % for ketoprofen. The FTIR and SEM analysis proved the incorporation of the drugs in the blend matrix.
Despite the worldwide vaccination effort against COVID-19, the demand for biocidal materials has increased. One promising solution is the chemical modification of polysaccharides, such as chitosan, ...which can provide antiviral activity through the insertion of cationic terminals. In this study, chitosan was modified with (4-carboxybutyl) triphenylphosphonium bromide to create N-phosphonium chitosan (NPCS), a quaternized derivative. The resulting NPCS samples with three degrees of substitution (15.6 %, 19.8 % and 24.2 %) were characterized and found to have improved solubility in water and alkaline solutions but reduced thermal stability. The particles zeta potential exhibits positive charges and is directly correlated with the degree of substitution of the derivative. In virucidal assays, all NPCS samples were able to inhibit 99.999 % of the MHV-3 coronavirus within 5 min at low concentrations of 0.1 mg/mL, while maintaining low cytotoxicity to L929 cells. In addition to its potential application against current coronavirus strains, NPCS could also be valuable in combating future pandemics caused by other viral pathogens. The antiviral properties of NPCS make it a promising material for use in coating surface and personal protective equipment to limit the spread of disease-causing viruses.
Cellulosic materials have gained a lot of attention in the last decades because of their abundancy, renewability and excellent physicochemical properties. Meanwhile, research on nanofibers has also ...been increasing with the aim of producing or modifying materials that can have a wide range of applications, such as tissue engineering, drug delivery, protective clothing and wound dressing. In order to produce these fibers, electrospinning is shown to be a promising and extensively used technique. Electrospun cellulosic fibers maintain the optimal characteristics of cellulose while improving its surface area to volume ratio and mechanical properties, in addition to the possibility of surface tailoring of bulk materials. However, there are several limitations related to the utilization of cellulose and most of its derivatives with the electrospinning technique. Poor solubility in most common solvents and inability to melt are major drawbacks. Thus, this review describes mostly recent research in which cellulose and its derivatives have been the feedstock for fabrication of nanofibers by electrospinning, exploring processing details and potential applications.
•The pandemic highlighted the need for new solutions to prevent SARS-CoV-2 viability on surfaces.•Chitosan can be quaternized with glycidyltrimethylammonium chloride in different proportions to ...introduce permanently cationized groups along its polymeric structure.•Quaternized chitosan derivatives demonstrated high efficacy in preventing viral and bacterial spread in vitro, indicating their potential for use in pandemic prevention.
SARS-CoV-2 caused a global pandemic with high transmission rates, even with widespread vaccination. In addition to isolation and prevention measures, it is important to find new solutions to inactivate the virus and prevent its viability on surfaces, such as clothing and face masks. Chitosan derivatives, with their antibacterial activity, biocompatibility, and non-toxicity, are a promising option for coating these components with virucidal materials. N-(2-hydroxypropryl)-3-trimethylammonium chloride, a quaternized chitosan derivative with degrees of substitution ranging from 59 to 93%, was synthesized. This derivative was used to coat cotton and polypropylene fabrics, such as face masks, without visibly affecting their morphology or filtering capacity. In vitro tests demonstrated that the coatings produced had high antiviral activity against coronavirus, with efficacy up to 99.99%, and were also bactericidal against E. coli and S. aureus. These results show that quaternized chitosan derivatives have great potential to be used as virucidal coatings, helping to prevent the spread of SARS-Cov-2 and other pathogens on surfaces, which can even be useful for the quick development of solutions for future pandemics.
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