Employment of chitosan in the removal of pollutants in fish processing effluents / [Emprego de quitosana na remoção de poluentes em efluentes de processamento de pescado]

The significant growth of the industrial sector in recent decades has led to an increase in the volume of waste, which if not properly destined, could cause serious environmental problems. In the context of aquaculture, liquid effluents with a high organic content are generated in large quantities in the fish processing industries, and if their disposal is carried out improperly, serious damage to the environment is caused. The general objective of this study is to evaluate: the efficiency of removal of COD and BOD, in addition to the influence on pH; alkalinity; chlorides; ammonia; nitrite; nitrate; phosphate; turbidity; total, fixed and volatile solids, from the effluent of fish processing treated by coagulation and sedimentation using the natural chitosan coagulant. pH 5.5 followed by pH 6 showed better results for the use of chitosan coagulant in the process of treatment by effluent coagulation of fish processing industry. Chitosan does not act on the parameters TVS, alkalinity, chlorides, ammonia, nitrite, nitrate, and phosphate, regardless of the dosage used. However, it acts on BOD, COD, TS, TFS and turbidity. Thus, the best dosage of chitosan is 0.25 g L-1 in optimized activity at pH of 5.5.

O crescimento expressivo do setor industrial nas últimas décadas acarretou o aumento do volume de resíduos, que, se não forem destinados adequadamente, poderão causar sérios problemas ambientais. No contexto da aquacultura, efluentes líquidos com um alto teor orgânico são gerados em grandes quantidades nas indústrias de processamento de pescado, e, se seu descarte for realizado de maneira inadequada, há sérios prejuízos ao ambiente. O objetivo geral deste estudo foi avaliar: a eficiência de remoção de DQO e DBO, além da influência sobre o pH, a alcalinidade, os cloretos, a amônia, o nitrito, o nitrato, o fosfato, a turbidez, os sólidos totais, fixos e voláteis, bem como do efluente do processamento de pescado tratado por coagulação e da sedimentação, utilizando-se o coagulante natural quitosana. O pH 5,5, seguido pelo pH 6, apresentou melhores resultados para uso do coagulante quitosana no processo de tratamento por coagulação de efluente de indústria de processamento de pescado. A quitosana não atua sobre os parâmetros STV, alcalinidade, cloretos, amônia, nitrito, nitrato e fosfato, independentemente da dosagem utilizada. Mas atua sobre DBO, DQO, ST, STF e turbidez. Assim, a melhor dosagem de quitosana é 0,25 g L-1 em atividade otimizada no pH de 5,5.

An overview of gastrointestinal mucus rheology under different pH conditions and introduction to pH-dependent rheological interactions with PLGA and chitosan nanoparticles.

This review discusses the physicochemical and mechanical properties of porcine gastrointestinal mucus from a rheological point of view. Considering mucus as a viscoelastic gel that functions as a biological barrier by limiting particles passage, lubricating the gastrointestinal tract, and protecting the stomach from gastric acids. The viscoelastic and protective properties of mucus are mainly produced by its mucin network, which is stabilized through electrostatic, hydrophobic and hydrogen bonding interactions. Otherwise, mucus rheology is determined by its polyanionic nature at physiological pH. At neutral pH, mucus presents a viscous behavior produced by chains crosslinking. While, at acidic pH, mucus exhibits an elastic behavior related with the extended conformation that produces mucus gelation at the stomach. Additionally, rheology studies the degree of adhesion between a polymer-mucus mixture through rheological synergism, and how it varies at different pH conditions. Finally, mucoadhesion phenomenon is exemplified with chitosan (cationic) and poly (lactic-co-glycolic) acid (anionic) polymers.

Design of Chitosan Nanocapsules with Compritol 888 ATO® for Imiquimod Transdermal Administration. Evaluation of Their Skin Absorption by Raman Microscopy.

PURPOSE: Design imiquimod-loaded chitosan nanocapsules for transdermal delivery and evaluate the depth of imiquimod transdermal absorption as well as the kinetics of this absorption using Raman Microscopy, an innovative strategy to evaluate transdermal absorption. This nanovehicle included Compritol 888ATO®, a novel excipient for formulating nanosystems whose administration through the skin has not been studied until now. METHODS: Nanocapsules were made by solvent displacement method and their physicochemical properties was measured by DLS and laser-Doppler. For transdermal experiments, newborn pig skin was used. The Raman spectra were obtained using a laser excitation source at 532 nm and a 20/50X oil immersion objective. RESULTS: The designed nanocapsules, presented nanometric size (180 nm), a polydispersity index <0.2 and a zeta potential +17. The controlled release effect of Compritol was observed, with the finding that half of the drug was released at 24 h in comparison with control (p < 0.05). It was verified through Raman microscopy that imiquimod transdermal penetration is dynamic, the nanocapsules take around 50 min to penetrate the stratum corneum and 24 h after transdermal administration, the drug was in the inner layers of the skin. CONCLUSIONS: This study demonstrated the utility of Raman Microscopy to evaluate the drugs transdermal penetration of in the different layers of the skin. Graphical Abstract New imiquimod nanocapsules: evaluation of their skin absorption by Raman Microscopy and effect of the compritol 888ATO® in the imiquimod release profile.

Development of curcumin-loaded chitosan/pluronic membranes for wound healing applications.

The emergence of new materials with improved antibacterial, anti-inflammatory and healing properties compared to conventional wound dressings has both social and economic appeal. In this study, novel chitosan-based (CTS) membranes containing curcumin (CUR) incorporated in Pluronic (PLU) copolymers were developed and characterized to obtain suitable properties for applications as a wound healing dressing. The mechanical, thermal, swelling, wettability, release and permeation properties were evaluated by DSC, TGA, water contact angle measurements, FTIR, fluorescence and microscopic techniques. Membranes containing PLU and CUR presented wettability close to the ideal range for interaction with cellular components (contact angle ~40-70°), improved mechanical properties, higher thermal stability, high swelling degree (>800%) and CUR release (~60%) compared to samples without PLU addition. A higher retention of CUR in the epidermis than in the dermis layer was observed, which also was confirmed by confocal microscopy. Furthermore, the CTS-PLU membranes loaded with CUR showed to be active against Staphylococcus aureus and Pseudomonas aeruginosa (MIC = 25 and 100 mg mL-1, respectively), the microbial species most present in chronic wounds. Overall, the CTS-PLU-CUR membranes presented suitable properties to act as a new wound healing dressing formulation and in vivo studies should be performed to confirm these benefits.

Use of chitosan as pharmaceutical excipient in ocular drug delivery systems: Sterilization and pharmacokinetics.

The use of chitosan as a pharmaceutical excipient in the ocular field is already established. Nevertheless, some aspects related to its ocular administration, such as sterilization and excipient's pharmacokinetics, remain unclear. So, in this study, we evaluated those two relevant aspects, related to chitosan administration in eye. We used chitosan-based ocular inserts (CI) as formulation model. CI were produced by solvent/casting method and sterilized by saturated steam. Sterilization was confirmed by direct inoculation of inserts in suitable microbiological growth media. Physicochemical characterization of inserts before and after sterilization was performed. Results suggested that, although steam sterilization changed the arrangement of the matrix, the heat and the humidity did not modify the structure of the main polymeric chain. Pharmacokinetics of CI radiolabeled with technetium-99m (99m Tc) was assessed by scintigraphic images and ex vivo biodistribution study, after ocular administration in male Wistar rats. Scintigraphic and images analysis and ex vivo biodistribution study showed that the insert remained mainly in the eye until 6 hr after administration and its degradation products began to migrate to the abdominal cavity after 18 hr. Together, these data represent an important step forward the manufacturing and the clinical application of CI in the ophthalmic field.

Chitosan oligosaccharide (COS): An overview.

The frequently studied polysaccharide, chitosan oligosaccharide/chitooligosaccharide (COS) is the major degradation product of chitosan/chitin via chemical hydrolysis or enzymatic degradation involving deacetylation and depolymerization processes. Innumerable studies have revealed in the recent decade that COS has various promising biomedical implications in the past analysis, current developments and potential applications in a biomedical, pharmaceutical and agricultural sector. Innovations into COS derivatization has broadened its application in cosmeceutical and nutraceutical productions as well as in water treatment and environmental safety. In relation to its parent biomaterials and other available polysaccharides, COS has low molecular weight (Mw), higher degree of deacetylation (DD), higher degree of polymerization (DP), less viscous and complete water solubility, which endowed it with significant biological properties like antimicrobial, antioxidant, anti-inflammatory and antihypertensive, as well as drug/DNA delivery ability. In addition, it is also revealed to exhibit antidiabetic, anti-obesity, anti-HIV-1, anti-Alzheimer's disease, hypocholesterolemic, calcium absorption and hemostatic effects. Furthermore, COS is shown to have higher cellular transduction and completely absorbable via intestinal epithelium due to its cationic sphere exposed on the more exposed shorter N-glucosamine (N-Glc) units. This paper narrates the recent developments in COS biomedical applications while paying considerable attention to its physicochemical properties and its chemical composition. Its pharmacokinetic aspects are also briefly discussed while highlighting potential overdose or lethal dosing. In addition, due to its multiple NGlc unit composition and vulnerability to degradation, its safety is given significant attention. Finally, a suggestion is made for extensive study on COS anti-HIV effects with well-refined batches.

Promising Chitosan-Coated Alginate-Tween 80 Nanoparticles as Rifampicin Coadministered Ascorbic Acid Delivery Carrier Against Mycobacterium tuberculosis.

The aim of this study was to design a nanocarrier system for inhalation delivery of rifampicin (RIF) in combination with ascorbic acid (ASC), namely constituted of sodium alginate coated with chitosan and Tween 80 (RIF/ASC NPs) as a platform for the treatment of pulmonary tuberculosis infection. A Box-Behnken experimental design and response surface methodology (RSM) were applied to elucidate and evaluate the effects of several factors on the nanoparticle properties. On the other hand, it was found that RIF/ASC NPs were less cytotoxic than the free RIF, showing a significantly improved activity against nine clinical strains of Mycobacterium tuberculosis (M. tb) in comparison with the free drug. RIF/ASC NPs had an average particle size of 324.0 ± 40.7 nm, a polydispersity index of 0.226 ± 0.030, and a zeta potential of - 28.52 ± 0.47 mV and the surface was hydrophilic. The addition of sucrose (1% w/v) to the nanosuspension resulted in the formation of a solid pellet easily redispersible after lyophilization. RIF/ASC NPs were found to be stable at different physiological pH values. In summary, findings of this work highlight the potential of the RIF/ASC NP-based formulation development herein to deliver RIF in combination with ASC through pulmonary route by exploring a non-invasive route of administration of this antibiotic, increasing the local drug concentrations in lung tissues, the primary infection site, as well as reducing the risk of systemic toxicity and hence improving the patient compliance.

Chitosan hydrogels containing nanoencapsulated phenytoin for cutaneous use: Skin permeation/penetration and efficacy in wound healing.

Although phenytoin is an antiepileptic drug used in the oral treatment of epilepsy, its off-label use as a cutaneous healing agent has been studied in recent years due to the frequent reports of gingival hyperplasia after oral administration. However, the cutaneous topical application of phenytoin should prevent percutaneous skin permeation. Therefore, the aim of this study was to evaluate the in vitro skin permeation/retention and in vivo effects of nanocapsules and nanoemulsions loaded with phenytoin and formulated as chitosan hydrogels on the healing process of cutaneous wounds in rats. The hydrogels had adequate pH values (4.9-5.6) for skin application, drug content of 0.025% (w/w), and non-Newtonian pseudoplastic rheological behaviour. Hydrogels containing nanocapsules and nanoemulsions enabled improved controlled release of phenytoin and adhesion to skin, compared with hydrogels containing non-encapsulated phenytoin. In vitro skin permeation studies showed that phenytoin permeation to the receptor compartment, and consequently the risk of systemic absorption, may be reduced by nanoencapsulation without any change in the in vivo performance of phenytoin in the wound healing process in rats.

Quercetin and 3-O-methylquercetin in vitro skin layers permeation/retention from hydrogels: why only a methoxy group difference determines different behaviors?

OBJECTIVES: The present study was designed to verify if quercetin (QCT), a flavonoid with antioxidant and antiviral activity, and 3-O-methylquercetin (3OMQ), a quercetin C3-methoxylated derivative, present differences in their behavior against complexation with ß-cyclodextrin (ß-CD) and the corresponding permeation/retention trhough porcine ear skin, when incorporated into hydroxypropyl methylcellulose (HPMC) or chitosan (CS) hydrogels. METHODS: The influence of ß-CD on the skin permeation/retention of QCT and 3OMQ from hydrogels is comparatively evaluated for both flavonoids using porcine ear skin in Franz cells model. The properties of the two flavonoids using the semi-empirical method Recife Model was studied. KEY FINDINGS: Quercetin presented higher skin retention compared with its C3-methoxy derivative 3OMQ. The best permeation/retention of QCT was observed when it was incorporated into CS hydrogel containing 5% ß-CD, whereas, for 3OMQ, the HPMC hydrogel containing 5% ß-CD was the best formulation. The flavonoids complexation with ß-CD in water occurred preferentially with the insertion of the B ring through the secondary OH rim. CONCLUSIONS: The dynamic molecular modeling revealed that the methyl group at C3 in 3OMQ molecule determined significant difference in its complexation with ß-CD, in comparison to its analogous QCT and that difference is coincident with the permeation behavior of these flavonoids, denoting a possible relationship with their molecular dynamics.

Targeted Drug Delivery and Treatment of Endoparasites with Biocompatible Particles of pH-Responsive Structure.

Biomaterials conceived for vectorization of bioactives are currently considered for biomedical, biological, and environmental applications. We have produced a pH-sensitive biomaterial composed of natural source alginate and chitosan polysaccharides for application as a drug delivery system via oral administration. The composite particle preparation was in situ monitored by means of isothermal titration calorimetry. The strong interaction established between the macromolecules during particle assembly led to 0.60 alginate/chitosan effective binding sites with an intense exothermic effect and negative enthalpy variation on the order of a thousand kcal/mol. In the presence of model drugs mebendazole and ivermectin, with relatively small and large structures, respectively, mebendazole reduced the amount of chitosan monomers available to interact with alginate by 27%, which was not observed for ivermectin. Nevertheless, a state of intense negative Gibbs energy and large entropic decrease was achieved, providing evidence that formation of particles is thermodynamically driven and favored. Small-angle X-ray scattering provided further evidence of similar surface aspects independent of the presence of drug. The physical responses of the particles to pH variation comprise partial hydration, swelling, and the predominance of positive surface charge in strong acid medium, whereas ionization followed by deprotonation leads to compaction and charge reversal rather than new swelling in mild and slightly acidic mediums, respectively. In vivo performance was evaluated in the treatment of endoparasites in Corydoras fish. Systematically with a daily base oral administration, particles significantly reduced the infections over 15 days of treatment. The experiments provide evidence that utilizing particles granted and boosted the action of the antiparasitic drugs, leading to substantial reduction or elimination of infection. Hence, the pH-responsive particles represent a biomaterial with prominent characteristics that is promising for the development of targeted oral drug delivery.

Biophysical and biological characterization of intraoral multilayer membranes as potential carriers: A new drug delivery system for dentistry.

The current study developed through layer-by-layer deposition a multilayer membrane for intraoral drug delivery and analyzed the biochemical, functional, and biological properties of this membrane. For that purpose, we designed a three-layer chlorhexidine-incorporated membrane composed by pure chitosan and alginate. The biochemical, functional, and biological properties were analyzed by the following tests: degradation in saliva medium; controlled drug release; water absorption, mass loss; pH analysis; and biocompatibility through fibroblast cell viability by MTT assay. All tests were conducted at three different periods (24, 48 and 72hours). The results demonstrated that hybrid membranes composed by alginate and chitosan with glycerol had greater water absorption and mass loss in buffer solution and in artificial saliva. The controlled drug release test revealed that the hybrid membrane exhibited greater drug release (0.075%). All chlorhexidine-incorporated membranes reduced the cell viability, and chitosan membranes with and without glycerol did not interfere with fibroblast viability. The biochemical and biophysical characteristics of the designed membranes and the findings of cell viability tests indicate great potential for application in Dentistry.

Floating ability and drug release evaluation of gastroretentive microparticles system containing metronidazole obtained by spray drying

Abstract Gastroretentive floating microparticles were developed and evaluated for the controlled metronidazole delivery for treatment of gastric disease. Floating microparticles, varying in proportions of chitosan and hydroxypropyl methylcellulose or ethylcellulose, were obtained by spray drying. Floating microparticles were characterized by physicochemical and in vitro studies, according to their floating ability and drug delivery. Microparticles presented mean diameter from 1.05 to 2.20 µm. The infrared spectroscopy confirmed the drug encapsulation and showed no chemical linkage between microparticles components. X-ray diffraction showed changes in the drug`s solid state, from crystalline to amorphous, indicating partial drug encapsulation, due to the presence of some crystalline peaks of metronidazole in microparticles. All microparticles floated immediately in contact of simulated gastric fluid and both floating and drug release profiles were dependent of microparticles composition. Microparticles samples constituted by chitosan and hydroxypropyl methylcellulose revealed the best relationship between floating duration and drug release, remaining floating during the occurrence of the drug release, ideal condition for the floating gastroretentive systems.

Films based on neutralized chitosan citrate as innovative composition for cosmetic application.

In this work, citrate and acetate buffers, were investigated as neutralizers to chitosan salts in order to provide biocompatible and stable films. To choose the appropriate film composition for this study, neutralized chitosan citrate and acetate films, with and without the plasticizer glycerol, were prepared and characterized by thickness, moisture content, degree of swelling, total soluble matter in acid medium, simultaneous thermal analysis and differential scanning calorimetry. Chitosan films neutralized in citrate buffer showed greater physical integrity resulted from greater thicknesses, lower moisture absorbance, lower tendency to solubility in the acid medium, and better swelling capacities. According to thermal analyses, these films had higher interaction with water which is considered an important feature for cosmetic application. Since the composition prepared in citrate buffer without glycerol was considered to present better physical integrity, it was applied to investigate hyaluronic acid release in a skin model. Skins treated with those films, with or without hyaluronic acid, show stratum corneum desquamation and hydration within 10min. The results suggest that the neutralized chitosan citrate film prepared without glycerol promotes a cosmetic effect for skin exfoliation in the presence or absence of hyaluronic acid.

Skin penetration and dermal tolerability of acrylic nanocapsules: Influence of the surface charge and a chitosan gel used as vehicle.

For an improved understanding of the relevant particle features for cutaneous use, we studied the effect of the surface charge of acrylic nanocapsules (around 150nm) and the effect of a chitosan gel vehicle on the particle penetration into normal and stripped human skin ex vivo as well as local tolerability (cytotoxicity and irritancy). Rhodamin-tagged nanocapsules penetrated and remained in the stratum corneum. Penetration of cationic nanocapsules exceeded the penetration of anionic nanocapsules. When applied on stripped skin, however, the fluorescence was also recorded in the viable epidermis and dermis. Cationic surface charge and embedding the particles into chitosan gel favored access to deeper skin. Keratinocytes took up the nanocapsules rapidly. Cytotoxicity (viability<80%), following exposure for ≥24h, appears to be due to the surfactant polysorbate 80, used for nanocapsules stabilization. Uptake by fibroblasts was low and no cytotoxicity was observed. No irritant reactions were detected in the HET-CAM test. In conclusion, the surface charge and chitosan vehicle, as well as the skin barrier integrity, influence the skin penetration of acrylic nanocapsules. Particle localization in the intact stratum corneum of normal skin and good tolerability make the nanocapsules candidates for topical use on the skin, provided that the polymer wall allows the release of the active encapsulated substance.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning electron microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were jointly reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24 h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

RESUMO O objetivo desta pesquisa foi planejar um novo sistema de liberação de fármacos direcionado ao cólon, utilizando quitosana. Estudaram-se as propriedades dos filmes a fim de obter informações úteis sobre a aplicação desses filmes compósitos. Utilizaram-se os filmes compósitos em sistema de bicamada para investigar a sua viabilidade como materiais de revestimento. Estudos de resistência à tração, grau de intumescimento, solubilidade, grau de biodegradação, no infravermelho por transformada de Fourier (FTIR), de calorimetria diferencial de varredura (DSC) e de microscopia eletrônica de varredura (SEM) mostraram que o filme compósito se formou quando a quitosana e a gelatina reagiram entre si. Os resultados mostraram que a mistura de proporção ótima foi de 6:4 de quitosana:gelatina. Resultados da liberação do fármaco in vitro indicaram que o sistema de revestimento de Eudragit e bicamada de quitosana/gelatina impediu a liberação de fármaco em fluido intestinal simulado (SIF) e em fluido gástrico simulado (SGF). Entretanto, a liberação de fármaco do comprimido revestido em bicamada no SCF aumentou ao longo do tempo e o fármaco foi quase completamente liberado após 24 h. Em geral, se obteve a forma de liberação dirigida ao cólon, utilizando filme complexo de quitosana/gelatina e sistema de revestimento multicamada.

Quitosana, gelatina, hidroxiapatita e β - trifosfato de cálcio, usados no processo de regeneração óssea: artigo de revisão / Chitosan, gelatin, hydroxyapatite and β - calcium triphosphate, used in the process of bone regeneration:review article

O objetivo da presente revisão é compilar informações acerca do uso de biopolímeros e fosfatos de cálcio no processo de regeneração óssea. Dentre os biopolímeros que merecem destaque podemos citar a quitosana pelo seu potencial osteoindutor e a gelatina, mais recentemente estudada no processo de reparação óssea, servindo com carreador. Os fosfatos de cálcio mais estudados e que merecem posição de destaque são a hidroxiapatita e o β-trifosfato de cálcio. Sabe-se que ambos apresentam capacidade de osteocondução e servem de substrato para acelerar a cicatrização de defeitos ósseos.

The objective of this review is to compile information about the use of biopolymers and calcium phosphatesin the process of bone regeneration. Among the biopolymers that are worth mentioning we can cite the osteoinductive potential by chitosan and gelatin more recently studied in bone repair process, serving with carrier. Calcium phosphates most studied and deserve a prominent position are hydroxyapatite and β-calcium triphosphate. It is known that both have the ability to serve as osteoconductive substrate and to accelerate the healing of bone defects.

Quitosana, gelatina, hidroxiapatita e β - trifosfato de cálcio, usados no processo de regeneração óssea: artigo de revisão / Chitosan, gelatin, hydroxyapatite and β - calcium triphosphate, used in the process of bone regeneration:review article

O objetivo da presente revisão é compilar informações acerca do uso de biopolímeros e fosfatos de cálcio no processo de regeneração óssea. Dentre os biopolímeros que merecem destaque podemos citar a quitosana pelo seu potencial osteoindutor e a gelatina, mais recentemente estudada no processo de reparação óssea, servindo com carreador. Os fosfatos de cálcio mais estudados e que merecem posição de destaque são a hidroxiapatita e o β-trifosfato de cálcio. Sabe-se que ambos apresentam capacidade de osteocondução e servem de substrato para acelerar a cicatrização de defeitos ósseos.AU

The objective of this review is to compile information about the use of biopolymers and calcium phosphatesin the process of bone regeneration. Among the biopolymers that are worth mentioning we can cite the osteoinductive potential by chitosan and gelatin more recently studied in bone repair process, serving with carrier. Calcium phosphates most studied and deserve a prominent position are hydroxyapatite and β-calcium triphosphate. It is known that both have the ability to serve as osteoconductive substrate and to accelerate the healing of bone defects.AU

Characterization of N-trimethyl chitosan/alginate complexes and curcumin release.

N-trimethyl chitosan of two quaternization degrees, DQ=20 and 80mol% and labeled as TMC20 and TMC80, were synthesized and characterized by (1)H NMR. Polyelectrolyte complexes (PECs) of TMC/alginate (TMC/ALG) were prepared at pHs 2, 7 and 10 by mixing the aqueous solutions of unlike polymers. The PECs were characterized through infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG) and wide-angle X-ray scattering (WAXS). Using the TMC of DQ=20 mol% and following the same methodology for preparing the PECs, beads of TMC20/ALG were obtained at pH 2 and loaded with curcumin (CUR) at pH 6.0-6.5. The morphology of the beads was evaluated by scanning electron microscopy (SEM). Studies in vitro of the controlled release of CUR from beads were investigated in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) and treated using conventional and partition-diffusion models. Results indicated that the beads based on TMC20 and ALG presented potential as drug-carrier to improve the solubility and biological activity of CUR at pH close to physiological one.

Programmed delivery of verapamil hydrochloride from tablet in a capsule device

The aim of the present work was to develop a programmed drug delivery system which would be able to release the drug after 6 h of lag time by use of hydrophilic polymers. The capsule body was made impermeable by use of formaldehyde vapor treatment, while the cap was untreated. The capsule was filled with two layered tablets (tablet-in-capsule), followed by a sodium bicarbonate:citric acid mixture (SBCM) and lactose as bulking agent. Sodium alginate, chitosan, HPMC K15 and chitosan:sodium alginate complex (CSAC) were used as the rate modulating layer. Through combined use of HPMC K15 and adjusting the ratio of CSAC, the desired lag time of 6 h was obtained. The effect of the bulking agents on the lag time were also studied and it was found that the lag time was decreased with higher amounts of lactose, and delayed dissolution and decreased lag time was observed at higher amount of effervescent mixture.

O objetivo do presente trabalho foi desenvolver sistema de liberação programada de cloridrato de verapamil capaz de liberação imediata do fármaco após 6 h de intervalo de tempo usando polímeros hidrofílicos. O corpo da cápsula foi impermeabilizado por tratamento de vapor de formaldeído, enquanto a tampa não foi submetida ao tratamento. Dois comprimidos foram inseridos na cápsula (comprimidos em cápsula) seguido de mistura de bicarbonato de sódio: ácido cítrico e lactose, utilizados como excipientes. O alginato de sódio, a quitosana, o HPMC K15 e o complexo quitosana:alginato de sódio foram utilizados para modular a razão de liberação do fármaco. A combinação entre o HPMC K15 e o ajuste da proporção do complexo quitosana:alginato de sódio permitiu a liberação do fármaco após 6 h. O efeito dos excipientes na liberação do fármaco foi também avaliado. Verificou-se que o tempo de latência foi reduzido na presença de maior quantidade de lactose, enquanto o menor tempo foi observado empregando maior concentração da mistura efervescente.

Development and in vitro evaluation of biopolymers as a delivery system against periodontopathogen microorganisms.

Periodontal disease is the major cause of tooth loss in adults. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are considered key pathogens in periodontitis. The treatment consists of oral hygiene education, instrumentation for removal of calculus (scaling), chemotherapy and periodontal surgery. Several agents are commercially available; these chemicals can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining. Hence, the search for alternative products continues and natural phytochemicals isolated from plants used as traditional medicine and the use of biomaterials are considered good alternatives. Chitosan and pullulan are polymers that have been proposed due to their favorable properties such as biocompatibility, biodegradability, and adhesion ability. They can be used as local delivery systems of active principles of plant extracts. Thymus vulgaris, Matricaria chamomilla, Croton lechleri, Calendula officinalis L. and Juliana adstringens Schl. are known to have medicinal activity, and they are used in Mexican traditional medicine. Their extracts were tested in vitro for antimicrobial activity against P. gingivalis and A. actinomycetemcomitans, using agar diffusion and microdilution methods. The antimicrobial activity of films from biopolymers with plant extracts was evaluated by measuring the zones of inhibition against the tested organisms. The aim of this study was to develop bioadhesive films from chitosan and pullulan with added plant extracts and determine the antimicrobial activity of films against periodontal pathogens.