Cannabidiol-loaded microparticles embedded in a porous hydrogel matrix for biomedical applications.

In this study, poly (lactic-co-glycolic acid) (PLGA) microparticles loaded with cannabidiol (CBD) were synthesized (PLGA@CBD microparticles) and embedded up to 10 wt% in a chondroitin sulfate/polyvinyl alcohol hydrogel matrix. In vitro chemical, physical, and biological assays were carried out to validate the potential use of the modified hydrogels as biomaterials. The microparticles had spherical morphology and a narrow range of size distribution. CBD encapsulation efficiency was around 52%, loading was approximately 50%. Microparticle addition to the hydrogels caused minor changes in their morphology, FTIR and thermal analyses confirmed these changes. Swelling degree and total porosity were reduced in the presence of microparticles, but similar hydrophilic and degradation in phosphate buffer solution behaviors were observed by all hydrogels. Rupture force and maximum strain at rupture were higher in the modified hydrogels, whereas modulus of elasticity was similar across all materials. Viability of primary human dental pulp cells up to 21 days was generally not influenced by the addition of PLGA@CBD microparticles. The control hydrogel showed no antimicrobial activity against Staphylococcus aureus, whereas hydrogels with 5% and 10% PLGA@CBD microparticles showed inhibition zones. In conclusion, the PLGA@CBD microparticles were fabricated and successfully embedded in a hydrogel matrix. Despite the hydrophobic nature of CBD, the physicochemical and morphological properties were generally similar for the hydrogels with and without the CBD-loaded microparticles. The data reported in this study suggested that this original biomaterial loaded with CBD oil has characteristics that could enable it to be used as a scaffold for tissue/cellular regeneration.

Chondrocyte Homeostasis and Differentiation: Transcriptional Control and Signaling in Healthy and Osteoarthritic Conditions.

Chondrocytes are the main cell type in articular cartilage. They are embedded in an avascular, abundant, and specialized extracellular matrix (ECM). Chondrocytes are responsible for the synthesis and turnover of the ECM, in which the major macromolecular components are collagen, proteoglycans, and non-collagen proteins. The crosstalk between chondrocytes and the ECM plays several relevant roles in the regulation of cell phenotype. Chondrocytes live in an avascular environment in healthy cartilage with a low oxygen supply. Although chondrocytes are adapted to anaerobic conditions, many of their metabolic functions are oxygen-dependent, and most cartilage oxygen is supplied by the synovial fluid. This review focuses on the transcription control and signaling responsible for chondrocyte differentiation, homeostasis, senescence, and cell death and the changes that occur in osteoarthritis. The effects of chondroitin sulfate and other molecules as anti-inflammatory agents are also approached and analyzed.

Proteoglycans orchestrate remodeling of prostatic cytoarchitecture after androgenic blockade in old gerbils.

BACKGROUND: The aim of this study was to evaluate modifications in proteoglycan morphology and composition in the prostatic stroma of 18-month-old gerbils after surgical castration, in association or not with an androgenic blockade. METHODS: The animals (n = 5) were sorted into groups subjected or not to antiandrogen treatment (flutamide 10 mg/kg/day) administered for the total postsurgery period and euthanized at 7- or 30-day postcastration; the control group consisted of intact animals. Tissue analysis included immunohistochemical assessment (perlecan and chondroitin sulfate) and proteoglycan morphology was analyzed by transmission electron microscopy. RESULTS: Chondroitin sulfate frequency was increased 7 days postcastration with an androgenic blockade. The presence of these carbohydrates was rare after 30 days of androgenic blockade treatment. There was a significant increase in the amount of perlecan in the prostate stroma from groups subjected to castration plus flutamide for 7 or 30 days. Ultrastructural analysis showed that the incidence of areas occupied by proteoglycans and basement membrane was altered by treatment. In addition, androgenic blockade results in changes in the amount, thickness, and morphology of these structures. At 30 days postcastration, with or without flutamide treatment, larger proteoglycans were common. CONCLUSIONS: In this study, in particular, the decrease in chondroitin sulfate after the longer period might be understood as a prostatic response to androgenic deprivation, while the high frequency and permanence of perlecan led to the assumption that its modulation could be androgen-independent. Length and form alterations in proteoglycans as well as associations among them and with the basement membrane were dynamic events in the prostate microenvironment.

Catalyst-Free Click Chemistry for Engineering Chondroitin Sulfate-Multiarmed PEG Hydrogels for Skin Tissue Engineering.

The quest for an ideal biomaterial perfectly matching the microenvironment of the surrounding tissues and cells is an endless challenge within biomedical research, in addition to integrating this with a facile and sustainable technology for its preparation. Engineering hydrogels through click chemistry would promote the sustainable invention of tailor-made hydrogels. Herein, we disclose a versatile and facile catalyst-free click chemistry for the generation of an innovative hydrogel by combining chondroitin sulfate (CS) and polyethylene glycol (PEG). Various multi-armed PEG-Norbornene (A-PEG-N) with different molecular sizes were investigated to generate crosslinked copolymers with tunable rheological and mechanical properties. The crosslinked and mechanically stable porous hydrogels could be generated by simply mixing the two clickable Tetrazine-CS (TCS) and A-PEG-N components, generating a self-standing hydrogel within minutes. The leading candidate (TCS-8A-PEG-N (40 kD)), based on the mechanical and biocompatibility results, was further employed as a scaffold to improve wound closure and blood flow in vivo. The hydrogel demonstrated not only enhanced blood perfusion and an increased number of blood vessels, but also desirable fibrous matrix orientation and normal collagen deposition. Taken together, these results demonstrate the potential of the hydrogel to improve wound repair and hold promise for in situ skin tissue engineering applications.

Biophysical properties of electrospun chitosan-grafted poly(lactic acid) nanofibrous scaffolds loaded with chondroitin sulfate and silver nanoparticles.

The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 µm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria (S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria (E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.

Hybrid polymer/lipid vesicle synthesis: Association between cationic liposomes and lipoplexes with chondroitin sulfate.

The association of cationic carriers with different anionic mucoadhesive biopolymers has been widely explored as an alternative to improve their delivery routes and specific targeting. This work presents a complete analysis of the association between chondroitin sulfate (CS) and cationic liposomes (CLs)/lipoplex (CL-pDNA). In this study, plasmid DNA (pDNA) was used as a genetic cargo for association with carriers. Firstly, we measured the stoichiometry of pseudo complexes and evaluated their colloidal properties, structural and morphological characteristics. Optimized CL-pDNA lipoplexes (positive z-potential) and CL-CS / CL-pDNA-CS (negative z-potential with CS mass ratio of 9% (w/w)) were further studied in detail. Small-angle X-ray scattering analysis and cryo-transmission electron microscopy micrographs revealed that the electrostatic interaction between CS and CL / CL-pDNA easily reorganized the lipid bilayers resulting in nanoscale uni/multilamellar vesicles. A high CS mass ratio (9% (w/w)) led to the reassembly of liposomal structure, wherein the pDNA was easily exchanged for CS chains, forming more than 50% of dense multilamellar vesicles. This data evidenced that the association between CS and CLs is not a conventional coating process since it generates complex and hybrid structures. We believe that these obtained colloidal data may be used in the future to investigate polymer-tailored nanocarriers and their production process. In brief, the colloidal study of hybrid structures may open interesting perspectives for developing novel carriers for drug and gene delivery applications.

A novel viewpoint in glaucoma therapeutics: enriched environment.

Glaucoma is one of the world's most frequent visual impairment causes and leads to selective damage to retinal ganglion cells and their axons. Despite glaucoma's most accepted risk factor is increased intraocular pressure (IOP), the mechanisms behind the disease have not been fully elucidated. To date, IOP lowering remains the gold standard; however, glaucoma patients may still lose vision regardless of effective IOP management. Therefore, the exclusive IOP control apparently is not enough to stop the disease progression, and developing new resources to protect the retina and optic nerve against glaucoma is a goal of vast clinical importance. Besides pharmacological treatments, environmental conditions have been shown to prevent neurodegeneration in the central nervous system. In this review, we discuss current concepts on key pathogenic mechanisms involved in glaucoma, the effect of enriched environment on these mechanisms in different experimental models, as well as recent evidence supporting the preventive and therapeutic effect of enriched environment exposure against experimental glaucomatous damage. Finally, we postulate that stimulating vision may become a non-invasive and rehabilitative therapy that could be eventually translated to the human disease, preventing glaucoma-induced terrible sequelae resulting in permanent visual disability.

Development and validation of a HILIC-HPLC-ELSD method for simultaneous determination of glucosamine hydrochloride and chondroitin sulfate in dietary supplements

Abstract The objective of the present study is to develop and validate a simple, selective and accurate hydrophilic interaction liquid chromatography - a high performance liquid chromatography incorporating an evaporative light scattering detector (HILIC-HPLC-ELSD) method for simultaneously determining glucosamine hydrochloride and chondroitin sulfate in dietary supplements. The chromatographic separation was carried out on a ZIC-HILIC column (150 mm x 4.6 mm x 5µm) in isocratic system mode with a mobile phase of acetonitrile, 30 mM ammonium formate and water (77:20:3, v/v/v) at pH 4.5, a column temperature of 35°C, a flow rate of 1 mL.min-1, and an injection volume of 5 µL. An evaporative light scattering (ELS) detector was used. Effective separation was achieved by means of analyte resolution of more than 1.5 with an analysis run time of approximately 20 minutes. The linearity of glucosamine hydrochloride and chondroitin sulfate ranged from 0.4 to 2.5 mg.mL-1. The limits of the detection and quantification of glucosamine hydrochloride were 20 and 80 mg.mL-1 respectively, while for chondroitin sulfate they were 80 and 400 mg.mL-1. All validation parameters satisfied the acceptance criteria in accordance with International Conference on Harmonisation (ICH) guidelines. The method was successfully applied to the assay of commercial dietary supplement samples

Biocompatible Hydrogel for Intra-Articular Implantation Comprising Cationic and Anionic Polymers of Natural Origin: In Vivo Evaluation in a Rabbit Model.

We describe the functional capability of a cross-linked hydrogel composed of sulfated glycosaminoglycans and a cationic cellulose by conducting trials on experimental animal models using intra-articular implants to treat an articular disease called osteoarthritis. Forty-eight mature New Zealand white rabbits were divided into three experimental groups: A, B, and C. Group A and B underwent unilateral anterior cruciate ligament transection (ACLT) of the right knee. Subsequently, both knees of group A were treated with the injectable formulation under study. Meanwhile, group B was treated with sterile PBS (placebo). The animals of group C were surgically operated in both knees: Commercial hyaluronic acid (HA) was implanted in the left knee, and the formulation under study was implanted in the right knee. After implantation, all specimens underwent several evaluations at 3, 6, and 12 months postoperatively. At 6 months, no significant differences were detected between the right and left knees of the different groups. However, significant differences were observed between both knees at 12 months in group C, with less cartilage damage in the right knees implanted with our hydrogel. Therefore, in vivo studies have demonstrated hydrogel safety, superior permanence, and less cartilage damage for long-term follow up 12 months after implantation for the formulation under study compared with commercial HA.

Pharmacological Activities of Sulfated Fucose-Rich Polysaccharides after Oral Administration: Perspectives for the Development of New Carbohydrate-Based Drugs.

Marine organisms are a source of active biomolecules with immense therapeutic and nutraceutical potential. Sulfated fucose-rich polysaccharides are present in large quantities in these organisms with important pharmacological effects in several biological systems. These polysaccharides include sulfated fucan (as fucoidan) and fucosylated chondroitin sulfate. The development of these polysaccharides as new drugs involves several important steps, among them, demonstration of the effectiveness of these compounds after oral administration. The oral route is the more practical, comfortable and preferred by patients for long-term treatments. In the past 20 years, reports of various pharmacological effects of these polysaccharides orally administered in several animal experimental models and some trials in humans have sparked the possibility for the development of drugs based on sulfated polysaccharides and/or the use of these marine organisms as functional food. This review focuses on the main pharmacological effects of sulfated fucose-rich polysaccharides, with an emphasis on the antidislipidemic, immunomodulatory, antitumor, hypoglycemic and hemostatic effects.

Oxygen-generating microparticles in chondrocytes-laden hydrogels by facile and versatile click chemistry strategy.

Currently, oxygen supply for in vitro cell culture is one of the major challenges in tissue engineering, especially in three-dimensional (3D) structures, such as polymeric hydrogels, because oxygen is an essential element for cells survival. In this context, oxygen levels must be maintained in articular cartilage to promote the differentiation, viability, and proliferation of chondrocytes due to the low level of oxygen presence in this region. Although some technologies employ oxygen-generating materials to add sufficient oxygen levels, the limitations and challenges of current technologies include the lack of controlled, sustained, and prolonged release of the oxygen. Moreover, the fabrication methods may leave some impurities or residues resulting in toxicity to the cells. "Click" chemistry is a facile, versatile, and compatible chemical strategy to engineer hydrogels for tissue engineering applications. Herein, we disclose the engineering of oxygen-generating microparticles in chondrocytes-laden hydrogels through a versatile catalyst-free tetrazine and norbornene inverse electron demand Diels‒Alder (iEDDA) click reaction. The hydrogels combine chondroitin sulfate (CS) and poly(ethylene glycol) (PEG) crosslinked in situ, displaying tunable rheological and mechanical properties, for sustained and prolonged oxygen-release. Gene expression analysis of the chondrocytes by real-time reverse transcription polymerase chain reaction (RT-PCR) demonstrated promising cell response within the engineered hydrogel.

Manufacturing micro/nano chitosan/chondroitin sulfate curcumin-loaded hydrogel in ionic liquid: A new biomaterial effective against cancer cells.

Chitosan/chondroitin sulfate (CHT/CS) curcumin-charged hydrogels were prepared through polyelectrolytic complexation (PEC) following two methodologies (PEC-CUR and PEC-T-CUR) and were applied on apoptosis of HeLa, HT29 and PC3 cancer cells. PEC-T-CUR (ionic liquid (IL) mixed using ultraturrax homogenizer) results show to be far better than for PEC-CUR (IL mixed using magnetic stirring), with IC50 being improved 5.13 times to HeLa cancer cells (from 1675.2 to 326.7 µg mL-1). PECs produced by this methodology presented favorable characteristics, such as particle size, hydrophobicity, pH swelling. Beyond this, the IL was quantitatively recovered in both cases. CUR entrapment levels were hugely loaded into PEC at around 100%. Swelling, dissolution/degradation, and pHpzc assays showed that PECs may positively act in several environments, releasing the CUR, the CHT and CS as well. Characterization through FTIR, SEM, TEM, TGA, DSC, and WAXS confirmed CUR presence in both types of PECs, and cytotoxic studies showed the significant anticancer effects of CUR-containing PECs.

Obtaining glycosaminoglycans from tilapia (oreochromis niloticus) scales and evaluation of its anticoagulant and cytotoxic activities: Glycosaminoglycans from tilapia scales: anticoagulant and cytotoxic activities.

Large amounts of by-products are generated during fish processing. The study aimed to assess whether tilapia scales are a potential source for obtaining glycosaminoglycans, as well as to determine their anticoagulant and cytotoxic/antiproliferative activities, against different tumor lines. The glycosaminoglycans were extracted, purified, and fractionated. The fractions that indicated the presence of uronic acid and sulfated GAGs were characterized by electrophoresis, NMR, and degree of sulfation (DS). The extraction process using the papain enzyme had a yield of 0.86%. Fraction V (FV) revealed the presence of chondroitin sulfate chains CS-A and CS-C, with DS of 0.146. FV demonstrated anticoagulant potential, as it was able to increase aPTT time. FV showed a cytotoxic effect for HTC metabolizing cells at 24, 48, and 72 h. However, it did not show activity for neuroblastoma cells in any of the evaluated times. The results indicate that the tilapia scales are a possible source for obtaining chondroitin sulfate, with potential use as anticoagulant and cytotoxic/antitumor.

Efficacy and Safety of Sodium Hyaluronate/chondroitin Sulfate Preservative-free Ophthalmic Solution in the Treatment of Dry Eye: A Clinical Trial.

Purpose: To evaluate the efficacy of a preservative free sodium hyaluronate/chondroitin sulfate ophthalmic solution (SH/CS-PF) in patients with dry eye disease (DED).Methods: This was a randomized phase IV, multicentric, prospective, double-blind clinical trial. Intent-to-treat (ITT) and per-protocol (PP) analyses were performed. Patients were assigned to receive either SH/CS-PF, Systane® Ultra (PEG/PG) or Systane® Ultra PF (PEG/PG-PF) for 90 days. A total of 326 patients were included in the ITT, and 217 in the PP analysis. Efficacy endpoints were goblet cell density, Nelson's grades (conjunctival impression cytology), tear break-up time (TBUT), Ocular Surface Disease Index (OSDI), and Schirmer's test. Other parameters included were tolerability, measured by the ocular symptomatology; and safety, measured through corneal staining, intraocular pressure, visual acuity and adverse events.Results: In the ITT, there was a significant increase in mean goblet cell density in all treatments compared with their baseline (28.4% vs 21.4% and 30.8%), without difference between arms (p = .159). Eyes exposed to SH/CS-PF, PEG/PG and PEG/PG-PF showed Grade 0-I squamous metaplasia (85.5%, 87.9% and 93.2%, respectively). Similar improvements were observed for TBUT (1.24 ± 2.3s vs 1.27 ± 2.4s and 1.39 ± 2.3s) and OSDI scores at day 90 (-8.81 ± 8.6 vs -7.95 ± 9.2 and -8.78 ± 9.8), although no significant intergroup difference was found. Schirmer's test also presented improvement compared to baseline (1.38 ± 4.9 vs 1.50 ± 4.7 and 2.63 ± 5.9), with a significantly higher variation for PEG/PG-PF. There were no significant differences between treatments for any tolerability and safety parameter, nor between ITT and PP analyses for any outcome.Conclusions: The topical application of SH/CS-PF is as effective, safe and well tolerated as that of PEG/PG or PEG/PG-PF. The results suggest that SH/CS-PF may lead to normalization of clinical parameters and symptom alleviation in patients treated for DED.

Chondroitin sulfate from fish waste exhibits strong intracellular antioxidant potential

Chondroitin sulfate (CS) is a type of glycosaminoglycan described as an antioxidant molecule that has been found in animal species such as fish. Tilapia (Oreochromis niloticus) represents an eco-friendly source of this compound, since its economical processing generates usable waste, reducing the negative environmental impact. This waste was used for CS extraction, purification, characterization by enzymatic degradation, and evaluation of its antioxidant effect. CS obtained from tilapia presented sulfation mainly at carbon 4 of galactosamine, and it was not cytotoxic at concentrations up to 200 µg/mL. Furthermore, 100 µg/mL of CS from tilapia reduced the levels of reactive oxygen species to 47% of the total intracellular reactive oxygen species level. The ability of CS to chelate metal ions in vitro also suggested an ability to react with other pathways that generate oxidative radicals, such as the Haber-Weiss reaction, acting intracellularly in more than one way. Although the role of CS from tilapia remains unclear, the pharmacological effects described herein indicate that CS is a potential molecule for further study of the relationship between the structures and functions of chondroitin sulfates as antioxidants.

Fucosylated Chondroitin Sulfates from the Sea Cucumbers Paracaudina chilensis and Holothuria hilla: Structures and Anticoagulant Activity.

Fucosylated chondroitin sulfates (FCSs) PC and HH were isolated from the sea cucumbers Paracaudina chilensis and Holothuria hilla, respectively. The purification of the polysaccharides was carried out by anion-exchange chromatography on a DEAE-Sephacel column. The structural characterization of the polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of nondestructive NMR spectroscopic methods. Both polysaccharides were shown to contain a chondroitin core [→3)-ß-d-GalNAc (N-acethyl galactosamine)-(1→4)-ß-d-GlcA (glucuronic acid)-(1→]n, bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in their pattern of sulfation: PC contained Fuc2S4S and Fuc4S in a ratio of 2:1, whereas HH included Fuc2S4S, Fuc3S4S, and Fuc4S in a ratio of 1.5:1:1. Moreover, some GalNAc residues in HH were found to contain an unusual disaccharide branch Fuc4S-(1→2)-Fuc3S4S-(1→ at O-6. Sulfated GalNAc4S6S and GalNAc4S units were found in a ratio of 3:2 in PC and 2:1 in HH. Both polysaccharides demonstrated significant anticoagulant activity in a clotting time assay, which is connected with the ability of these FCSs to potentiate the inhibition of thrombin and factor Xa in the presence of anti-thrombin III (ATIII) and with the direct inhibition of thrombin in the absence of any cofactors.

MCM-41/chondroitin sulfate hybrid hydrogels with remarkable mechanical properties and superabsorption of methylene blue.

This paper describes the synthesis of hybrid hydrogels based on chondroitin sulfate (CS) and mesoporous silica (MCM-41). The combination of the CS network and surface-modified MCM-41 yields resilient hybrids with a high water absorption power and excellent capacity for the removal of methylene blue (MB). In this system, two types of solute transport mechanisms exist: absorption and adsorption. The effect of MCM-41 on the physical-chemical properties of the hydrogels was assessed over a wide pH scale, and the absorption kinetics and isotherms of MB were studied by theoretical models. The mechanical properties of the hydrogels, such as the modulus of elasticity, yield strength, modulus of resilience, and fracture toughness, were significantly improved. This hydrogel exhibited high performance for water absorption (4000 % beyond its initial weight) and removal of MB (3982 ± 123.6 mg g-1), while the pure hydrogel removed 2912 ± 163.8 mg g-1.

Drug polarity effect over the controlled release in casein and chondroitin sulfate-based hydrogels.

This study compared the controlled release of two drugs: vitamin-B12, and l-dopa from hydrogels based on 50% of casein (CAS, a protein), 50% of chondroitin sulfate (CS, a polysaccharide) and different amounts of SiO2. The results indicated that the incorporation of 5% of SiO2 to the materials, allowed the best organization, distribution, and diameter of the pores, which are responsible for ensuring a more controlled release. Also, the matrices were not efficient in releasing vitamin-B12, but it successfully released l-dopa. It happened because vitamin-B12 is highly hydrophilic, interacting more with the medium than with the CAS/CS matrix, while l-dopa is less polar than vitamin-B12, interacting more with the CAS/CS matrix. It is worth mentioning that all synthesized hydrogels were non-toxic to the cells as showed by the in vitro assay. This work also demonstrated the importance of evaluating drug delivery devices using drugs of different polarities before stating if they are efficient or not.

Development and evaluation of dapsone tablets coated for specific colon release.

Objective: Drug release systems based on colonic microbiota have been explored with the use of polysaccharides, which are biodegradable. In order to modulate the release into the colon, dapsone tablets were developed, coated with Surelease® and chondroitin sulfate (SC).Methods: The formulation was developed using the wet granulation method, in the form of 9-millimetre circular tablets. The coating was applied in a perforated basin-type coating using different proportions of Surelease® and chondroitin sulfate. The tablets were assessed according to the criteria of mean weight, hardness, and friability. The dissolution test was performed in the dissolver IV apparatus, in media simulating the gastrointestinal system environments (pH 1.2-pH 6.0 and pH 7.2) for 420 min. The results were analyzed by statistical analysis and factorial design.Results: The results of mean weight, hardness, and friability met the pharmacopeial specifications. In the dissolution test, the results obtained demonstrated that Surelease® is able to offer effective protection to the drug, releasing minimum rates when used at 6% or 10% of the tablet's weight gain. The experiments showed that the drug was not able to spread through the coatings manufactured exclusively with Surelease® or even when SC was incorporated in different proportions. Only in the formulation where SC was included in the highest proportion (10%), and the weight gain of the tablet was lower (6%), the release of dapsone increased, reaching 9.5% of drug released. Through factorial planning, it was observed that the drug release rate increases when the weight gain of the tablet remains at the lower level (6%), while the amount of polysaccharide is increased (90:10).Conclusions: The data indicate that the proportion of polysaccharide for ethyl cellulose in the film and the thickness of the coating are the key parameters in controlling the release of the drug from the system.

pH-responsive hybrid hydrogels: Chondroitin sulfate/casein trapped silica nanospheres for controlled drug release.

In this study, the materials were synthesized by chemically crosslinking chondroitin sulfate (CS), casein (CAS), and silica nanospheres (SiO2), creating a highly crosslinked network. The hydrogel release profile was adaptable (that is, it could be faster or slower as needed) simply by changing the polymeric proportion. The incorporation of 5% of silica nanospheres, in mass, for all CAS/CS matrices promoted a better-controlled and sustained release of l-dopa, focusing on the matrix based on 70% of CAS, 30% of CS and 5% of silica, whose l-dopa release lasted for 87 h. Besides, hydrogels are cytocompatible. These new hydrogels can be considered highly attractive materials to be used for controlled and sustained drug release purposes, as well as scaffolds and wound dressing systems.