Comparação entre Reciproc Blue e quatro instrumentos réplicas: aspectos metalúrgicos, geometria, comportamento em torção e flexão / Comparison between Reciproc Blue and four replicalike instruments: metallurgical aspects, geometry, and behavior in torsion and flexion

A introdução da liga NiTi na endodontia proporcionou a fabricação de instrumentos com excelentes propriedades mecânicas, e uma das principais características é a possibilidade de alteração das temperaturas de transformação da liga, o qual pode possibilitar a presença de martensita em temperatura ambiente e consequentemente um efeito memória de forma. Entretanto, alguns dos sistemas comercializados atualmente possuem pouca ou nenhuma informação científica relatando suas propriedades mecânicas, características de design e métodos de fabricação. O objetivo deste trabalho foi comparar características geométricas, metalúrgicas e propriedades mecânicas (resistência à torção e flexão) de instrumentos Reciproc Blue (VDW, Munique, Alemanha), e quatro sistemas reciprocantes réplicas. Um total de 39 instrumentos de cada um dos sistemas reciprocantes, Reciproc Blue (RB), Prodesign R (PDR), V File (VF), V+ File (V+) e Univy One (UO) foram utilizados na pesquisa. O programa de Image J foi utilizado para mensuração dos diâmetros a cada milímetro da parte ativa e da área da seção transversal a 3 mm da ponta dos instrumentos. Imagens de MEV da parte ativa foram realizados para avaliar o acabamento superficial dos instrumentos. A composição atômica, fases presentes e temperaturas de transformação foram verificadas através de EDS, DRX e DSC, respectivamente. A flexibilidade foi aferida através de ensaios de dobramento até 45º conforme a especificação ISO 3630-1, e os ensaios de resistência à torção foram realizados de acordo com a especificação Nº28 ANSI/ADA. Todos os instrumentos apresentaram uma quantidade aproximadamente equiatômica de níquel e titânio. A análise qualitativa das fases cristalinas realizada através de ensaios de DRX, demonstrou a predominância de Fase R em todos os grupos, com exceção do grupo UO que apresenta uma mistura de fase R e martensita B19'. Na avaliação da área da seção, o instrumento RB obteve valores intermediários, os instrumentos PDR e V+ possuem menores valores e os instrumentos VF e UO possuem maiores valores. Observou-se grande impacto da geometria sobre as propriedades mecânicas, sendo que aqueles sistemas que apresentavam menor área que RB (PDR, V+) mostraram-se mais flexíveis e menos resistentes à torção (p<0.05), e o instrumento VF que teve maior área apresentou, como esperado, menos flexibilidade (p<0.05) e resistência torcional semelhante (p>0.05). A única exceção se deu com o sistema UO, que embora apresentasse uma maior área de seção, mostrou-se mais flexível e menos resistente à torção, provavelmente por influência da maior quantidade de martensita presente à temperatura ambiente. Nenhum dos instrumentos réplicas avaliados apresentaram características e comportamento mecânico iguais ao sistema padrão RB. Sugere-se que mais estudos devem ser realizados para a comparação do comportamento clínico destes instrumentos.

The introduction of NiTi alloy in endodontics has allowed the manufacturing of instruments with excellent mechanical properties, and one of the main characteristics is the ability to change alloy's transformation temperature, which can enable the presence of martensite at room temperature and consequently favor a shape memory effect. However, some of the currently marketed systems have limited or no scientific information regarding their mechanical properties, design characteristics, and manufacturing methods. The aim of this study was to compare the geometric characteristics, metallurgical aspects, and mechanical properties (torsional and flexural strength) of Reciproc Blue instruments (VDW, Munich, Germany) with four replica-like reciprocating systems. A total amount of 39 instruments from each reciprocating system, namely Reciproc Blue (RB), Prodesign R (PDR), V File (VF), V+ File (V+), and Univy One (UO), were used in the study. The Image J program was used to measure the diameters at every millimeter along the instruments active portion and the cross-sectional area at 3 mm from the instrument tip. SEM images of the active portion were obtained to evaluate the surface finishing of the instruments. Atomic composition, phases present, and transformation temperatures were determined through EDS, XRD, and DSC analyses, respectively. Flexibility was assessed by bending tests up to 45° according to ISO 3630-1 specifications, and torsional strength tests were performed according with ANSI/ADA Specification No. 28. All instruments exhibited an approximately equiatomic composition of nickel and titanium. Qualitative analysis of the crystalline phases using XRD tests demonstrated the predominance of the R-phase in all groups, except for the UO group, which exhibited a mixture of Rphase and B19' martensite. In terms of diameter and cross-sectional area evaluation, the RB instrument obtained intermediate values, while the PDR and V+ instruments had smaller values, and the VF and UO instruments had larger values. A significant impact of geometry on mechanical properties was observed, with systems exhibiting a smaller area than RB (PDR, V+) being more flexible and less torsion-resistant (p<0.05), and the VF instrument with a larger area showed, as expected, less flexibility (p<0.05) and similar torsional resistance (p>0.05). The only exception was the UO system, which, despite having a larger geometric configuration, exhibited greater flexibility and less torsional resistance, likely due to the higher amount of martensite present at room temperature. None of the replica-like instruments evaluated showed identical characteristics and mechanical behavior to the standard RB system. Further studies are suggested to compare the clinical performance of these instruments.

Evaluation of Physiochemical Properties, Thermal Behavior and Phytopharmaceutical Potential of Citrus aurantium’s Essential Oil

The study investigates the therapeutic potential of the Citrus aurantium var. amara essential oil extracted from the blossoms of the bitter orange plant by examining its chemical composition, thermal stability, and potency against infectious disease-causing pathogens. Initially, the volatile components of the essential oil were evaluated by obtaining a chromatographic fingerprint using HPTLC and FTIR spectrum identification. Furthermore, a thermal profile of the essential oil was obtained using the thermogravimetric-differential thermal analysis and differential scanning calorimetric analysis. A predetermined set of antibiotic-resistant microorganisms were used to examine the antibacterial activity of the essential oil. Lastly, its anti-inflammatory activity was assessed using the albumin denaturation assay. The research concluded that the Citrus aurantium var. Amara essential oil exhibits potential therapeutic characteristics which can be further explored through in vivo studies.

Preparação e caracterização de nanocarreadores de beta-lactose à base de pectina e lisozima / Preparation and characterization of beta-lactose nanocarriers based on pectin and lysozyme

O objetivo deste trabalho foi preparar e caracterizar nanocarreadores via auto-organização a partir da pectina de citros e lisozima para o encapsulamento da ß-lactose. Foram estudadas três condições de interação entre os biopolímeros variando a razão molar pectina/lisozima (3:1, 2:1, 1:1, 1:2 e 1:3), o pH e o tempo de aquecimento. A confirmação da interação foi determinada por espectroscopia no infravermelho por transformada de Fourier (FTIR) e por calorimetria de varredura diferencial (DSC). Os espectros de infravermelho evidenciaram que ligações de hidrogênio foram as principais forças envolvidas na formação dos nanocarreadores e sugeriram a ausência de ß-lactose livre na superfície das nanopartículas. Os termogramas evidenciaram que as nanopartículas formadas na presença de ß-lactose têm maior estabilidade térmica do que as nanopartículas sem ß-lactose. Para ambas as formulações estudadas, na presença e na ausência de ß-lactose, a formação das nanopartículas ocorreu entre os valores de pKa e ponto isoelétrico (pI) da pectina e lisozima, respectivamente, sendo a melhor razão de interação pectina/lisozima 1:2, em pH 10, a 80 ºC por 30 min. As nanopartículas foram formadas via auto-organização e todos as partículas apresentaram distribuição de tamanho homogênea, formato esférico, diâmetro inferior a 100 nm e carga superficial negativa. A morfologia e o tamanho das partículas pouco alteraram com a incorporação da -lactose. A eficiência de encapsulação (EE) da ß-lactose foi superior a 96% para as concentrações estudadas. Ensaios preliminares in vitro, em células epiteliais de câncer de cólon (HCT-116), evidenciaram que as nanopartículas formadas são capazes de adentrar no meio intracelular, possivelmente, por via endocitose

This work aimed to prepare and characterize nanocarriers via self-assembly using citrus pectin and lysozyme for ß-lactose encapsulation. Three interaction conditions between the biopolymers were studied, varying the pectin/lysozyme molar ratio (3:1, 2:1, 1:1, 1:2 and 1:3), pH and heating time. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) determined the interaction's confirmation. The infrared spectra showed that hydrogen bonds were the main forces involved in the formation of nanocarriers and suggested the absence of free ß-lactose on the surface of the nanoparticles. The thermograms showed that nanoparticles formed in the presence of ß-lactose have greater thermal stability than nanoparticles without ß-lactose. For both formulations studied, in the presence and absence of lactose, the formation of nanoparticles occurred between the pKa and isoelectric point (pI) values of pectin and lysozyme, respectively, with the best pectin/lysozyme interaction molar ratio 1:2, at pH 10, at 80 °C for 30 min. Nanoparticles were formed via self-assembly, and all particles presented homogeneous size distribution, spherical shape, diameter less than 100 nm, and negative surface charge. The morphology and size of the particles changed little with the incorporation of ß-lactose. The encapsulation efficiency (EE) of ß-lactose was higher than 96% for the concentrations studied. Preliminary in vitro assays in colon cancer epithelial cells (HCT-116) showed that the nanoparticles formed are capable of entering the intracellular medium, possibly via endocytosis

Caracterização mecânica, termodinâmica e química de fios CuNiTi ­ um estudo comparativo clínico e laboratorial / Mechanical, thermodynamic and chemical characterization of CuNiTi wires ­ a clinical and laboratory comparative study

Introdução: Os fios Copper Ni-Ti (CuNiTi) possuem indicações de uso clínico específicas, permanecendo no ambiente bucal por um longo período. Por esse motivo suas características mecânicas, termodinâmicas e estruturais devem ser preservadas durante todo o período de uso. Objetivos: Investigar se ocorrem alterações no comportamento mecânico, termodinâmico, estrutura e composição química superficial em fios CuNiTi 35°C submetidos ao envelhecimento in vivo (uso clínico) e in vitro (termociclagem), evidenciando as possíveis diferenças entre os métodos de envelhecimento. Material e Métodos: A amostra total foi constituída de 30 arcos pré-contornados 0.016", termodinâmicos com adição de cobre, e temperatura austenítica final (Af) de 35°C, da marca Ormco®. As análises destes fios resultaram em dois capítulos. Para o experimento clínico, 10 unidades de fios foram instaladas em 05 pacientes e permaneceram em meio bucal durante 30, 60 e 90 dias, e 05 fios foram analisados como recebidos (CR). A cada período, um hemiarco completo mais 1/3 (um terço) do hemiarco inferior direito foi retirado para análises. Para o experimento in vitro os 15 fios restantes foram submetidos à termociclagem para simulação do envelhecimento em ambiente oral durante 30 (600 ciclos), 60 (1200 ciclos) e 90 dias (1800 ciclos) com variação de temperatura entre 5°C e 55°C, com banhos de 90 segundos em cada temperatura, e transição de 15 segundos entre os banhos. Após cada período de envelhecimento in vivo e in vitro, os fios foram submetidos a um teste de padronização das suas dimensões através da medição dos diâmetros com paquímetro, Microscopia Eletrônica de Varredura (MEV), Espectrometria por Raios X Fluorescentes (FRX), ensaios de tração uniaxial e ensaio de Varredura Diferencial de Calorimetria (DSC). Resultados: No capítulo 1 a comparação entre os fios CR e os envelhecidos revelou que não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af, independentemente do tempo de permanência em boca. Foram encontrados predominantemente Ni, Ti, Cu e Al nas amostras, além de outros elementos químicos em concentrações variadas. No capítulo 2 não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af entre as amostras, independentemente do tempo ou do método de envelhecimento. Conclusão: As análises laboratoriais dos fios envelhecidos in vivo e in vitro foram comparadas, evidenciando que as características mecânicas, termodinâmicas e químicas dos fios permanecem estáveis mesmo até 90 dias de uso clínico ou 1800 ciclos de termociclagem. O método de envelhecimento in vitro se mostra uma alternativa viável para a análise destes parâmetros, em substituição aos métodos in vivo (AU).

Introduction: Copper Ni-Ti wires (CuNiTi) have specific indications for clinical use, remaining in the oral environment for a long period. For this reason, their mechanical, thermodynamic and structural characteristics must be preserved throughout the period of use of these materials. Objectives: To investigate whether there are changes in the mechanical, thermodynamic, structure and surface chemical composition of CuNiTi 35°C wires subjected to in vivo aging (clinical use) and in vitro (thermocycling), highlighting the possible differences between the aging methods. Material and Methods: The total sample was obtained from 30 pre-contoured Ormco® 0.016 thermodynamic archwires with copper addition and austenitic final temperature (Af) of 35°C. The analysis of these archwires resulted in two articles. For the clinical experiment, 10 units of wires were installed in 05 patients and remained in the oral environment for 30, 60 and 90 days, and 05 wires were analyzed as received. At each period, a complete hemiarch plus 1/3 of the right lower hemiarch was removed for analysis. For the in vitro experiment, the 15 remaining wires underwent thermocycling to simulate the aging of the oral environment for 30 (600 cycles), 60 (1200 cycles) and 90 days (1800 cycles) with a temperature range between 5°C and 55°C, with 90 second baths at each temperature, and 15 second transition between baths. After each in vivo and in vitro aging period, the wires underwent to a standardization test of their dimensions, by defining the diameters with a caliper, Scanning Electron Microscopy (SEM), Fluorescent X-Ray Spectrometry (FRX), tests of Uniaxial traction and Differential Scanning Calorimetry (DSC) test. Results: In chapter 1, the comparison between CR and aged wires revealed that there was no significant difference between the sample diameters, the forces obtained or even the temperatures Af, regardless the time spent in the mouth. Predominantly Ni, Ti, Cu and Al were found in the samples, in addition to other chemical elements in different concentrations. In chapter 2 there was no significant difference between the diameters of the samples, the forces obtained or even the temperatures Af between the samples, regardless of time or aging method. Conclusion: The comparison of the laboratoral analyzes of the archwires aged in vivo and in vitro showed that the mechanical, thermodynamic and the surface chemical characteristics were stable, even up to 90 days of clinical use or 1800 thermocycling cycles. The in vitro aging method is a viable alternative for the analysis of these parameters, replacing the in vivo methods (AU).

Pharmaceutical polymorphism of a 5´-O-oxalatoyl prodrug of zidovudine (azidothymidine)

The importance of polymorphism in pharmaceuticals makes its study relevant. The aim of this study was to investigatethe solid-state forms in which 3´-azido-2´, 3´-dideoxi-5´-O-oxalatoyl-thymidinic acid (AZT-Ac), a zidovudine (AZT)prodrug with improved pharmacokinetic properties, may exist. Samples were prepared using different crystallizationconditions and characterized using powder X-ray diffraction, solid-state nuclear magnetic resonance, differentialscanning calorimetry, thermogravimetry, and hot-stage microscopy. Pharmaceutical relevant properties such assolid-state stability and intrinsic dissolution rate (IDR) at 37°C in simulated gastric fluid (SGF) were also evaluated.AZT-Ac was found to able to exist as a crystalline polymorph (AZT-Ac-C) and an amorphous phase (AZT-Ac-A),which were thoroughly characterized. At 40°C/75% relative humidity (RH), AZT-Ac-A, in part, devitrified toAZT-Ac-C and partially hydrolyzed to AZT after 7 and 14 days of storage, respectively. AZT-Ac-C was physicallystable at 40°C/75% RH but partly hydrolyzed to AZT after 14 days of storage. In SGF, AZT-Ac-C exhibited a linearID profile and provided an ID rate of 0.494 mg/min/cm2, whereas AZT-Ac-A exhibited a nonlinear profile. Therefore,the crystalline form demonstrated the advantages over the amorphous one in terms of solid-state stability and IDR, butthe approaches to enhance its stability should be considered for further formulation of this prodrug.

Thermal analysis of some novel pyrimidine derivatives / Análisis térmico de algunos nuevos derivados de pirimidina

SUMMARY Some new pyrimidine derivatives have been synthesized and their decomposition characteristics have been studied by thermogravimetric and differential scanning calorimetric analysis. The thermal stability and some kinetics parameters of decomposition were evaluated from thermograms. It is observed that depending upon the structure, substitutions, thermal stability and decomposition kinetics varies in different compounds.

RESUMEN Se sintetizaron algunos nuevos derivados de pirimidina y se estudiaron sus características de descomposición mediante análisis termogravimétrico y calorimétrico diferencial de barrido. La estabilidad térmica y algunos parámetros cinéticos de descomposición se evaluaron a partir de los respectivos termogramas. Se observa que, dependiendo de la estructura y las sustituciones, la estabilidad térmica y la cinética de descomposición varían entre los diferentes compuestos.

Advances on Characterization of Lyotropic Liquid Crystals as Drug Delivery System / 中国药学杂志

Lyotropic liquid crystal(LLC) is generally a kind of micelle association formed by self-assembly of amphiphilic lipid polymers in polar solvents. It have been applied in the study of drug delivery of administration of oral, skin injection, ocular, and cavity channel routes(including buccal cavity, nasal cavity, vagina), et al. Medical liquid crystal mainly includes lamellar phase, inverse hexagonal phase and inverse cubic phase. Inner assembling order in different structures of liquid crystals will affect the drug localization, viscosity, molecular interactions, and further drug release in vitro and in vivo, pharmacokinetics and so on. Thus, it is very important to characterize their microstructures. In this article, the characterization methods of LLC microstructures are comprehensively described based on the research of LLC as drug delivery carrier and related literatures, which can provide reference for further study of LLC drug delivery system.

Preparation and characterization of bioadhesive Bletilla striata polysaccharide and sodium alginate microspheres loaded with Panax notoginseng saponins / 中草药

Objective: Because of the adhesion of Bletilla striata polysaccharide (BSP), it was mixed with sodium alginate (SA) as a composite carrier to prepare mucoadhesive PNS-BSP composite microspheres. Panax notoginseng saponins (PNS) dispersion with sustained release property was used as an encapsulating drug. Methods: The composite microsphere was prepared by ion cross-linking method. The formulation process was investigated and optimized by single factor test and orthogonal design. The microspheres were evaluated by scanning electron microscope (SEM), particle size distribution, DSC, swelling properties, in vitro mucoadhesive properties, and in vitro release characteristics. Results: PNS-BSP composite microspheres had good roundness, rough surface and wrinkles. The microspheres showed a narrow size distribution. PNS was uniformly dispersed in microspheres in an amorphous state. The microspheres prepared by the best prescription process were stable in process and reproducible. Compared with the microspheres prepared by directly adding PNS, the drug loading, encapsulation efficiency and yield of PNS dispersion microspheres were increased significantly, which were 10.34%, 51.25%, and 82.21%, respectively. The drug loading, encapsulation efficiency, and yield were 4.04%, 12.16%, and 61.35% of PNS microspheres. The addition of BSP increased the swelling properties of the SA microspheres, and significantly increased the retention rate in the stomach of rats. The release of ginsenoside Rg1 in PNS-BSP microspheres was released slower compared to PNS. Conclusion: The bioadhesion of microspheres was increased by the addition of BSP. The drug loading, encapsulation efficiency, and yield of the microspheres were increased by the preparation of PNS as a dispersion, and the microspheres also had a certain sustained-release effect.

Crystal form Analysis of Felodipine and Its Preparations / 中国药学杂志

OBJECTIVE: To clarify the crystal forms of the active pharmaceutical ingredient and preparations of felodipine from different sources, and explore the relationship between quality and efficacy of felodipine and its crystal form. METHODS: Crystal form characterization of the active pharmaceutical ingredient from different sources was carried out by powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and differential scanning calorimetry (DSC). The Origin software was used to analyze the crystal forms of felodipine in the sample preparations from different sources. Biological evaluation in vivo was conducted by using whole animals. RESULTS: There were some differences in the crystal state of the active pharmaceutical ingredient from different sources, but the main components were basically the same, all of which were type I. Biological studies showed significant differences in the main pharmacokinetic parameters of felodipine sustained release tablets from different sources. Among them, the ρmax, tmax, t1/2, and AUC0-t had maximal 1.8, 1.4, 8.2 and 1.5 times of differences. CONCLUSION: Although the main crystal forms of felodipine bulk drug from different origins are consistent, the crystal state significantly changes after the preparation process. This finding is of important scientific significance to guide the improvement of process and product quality.

Preparation and in vitro/in vivo evaluation of polydatin solid dispersion / 中草药

Objective: Polydatin solid dispersion (PD-SD) was prepared for improving bioavailability. Methods: In this study, PD-SD was prepared by solvent evaporation method with dissolution as index for improving bioavailability. The physicochemical properties of PD-SD were evaluated by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray power diffraction (XRD), and scanning electron microscope (SEM). HPLC was employed to determine the plasma concentration of PD-SD with PD crude drug as reference group in rats after oral administration. Results: FT-IR revealed that there was no new chemical bond between drug and carrier. DSC and XRD results indicated that PD in PD-SD was amorphous. SEM results showed that the morphology of PD-SD was close to irregular globular. The AUCs of PD-SD and PD were 328.79 and 139.70 μg·min/mL after oral administration, respectively. Conclusion: PD-SD is prepared by simple technology. PD-SD significantly improved the in vitro dissolution and oral bioavailability of PD in rats.

Effect of essential oil from asarum on percutaneous delivery of sinapine and its mechanism / 中草药

Objective: To study the enhancing effect of essential oil from asarum (EOA) on percutaneous delivery of sinapine and its mechanism. Methods: Transepidermal water loss (TEWL) was determined with Vapo Meter to evaluate the decrease of skin barrier by asarum essential oil. In vitro permeation of sinapine through rat skin was performed in the presence or absence of EOA, and the permeated cumulative amount and retention of sinapine were compared. In vivo percutaneous test was further performed to estimate the improvement of EOA on percutaneous delivery of sinapine. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimeter (DSC) were used to evaluate the changes of lipid and protein in stratum corneum. Results: TEWL value increased after the treatment of EOA, which indicated the decrease of skin barrier. The permeated cumulative amount and retention of sinapine in the presence of EOA were higher than those in the absence of EOA, and in vivo percutaneous test further confirmed this issue. After EOA treatment, the lipid and protein disorder could be observed from ATR-FTIR and DSC map, which indicated the increasing of skin permeability. Conclusion: EOA can enhance the percutaneous delivery of sinapine through improving the disorder of lipid and protein of stratum corneum.

Preparation of PEGylated graphene oxide nanoparticles loaded with oridonin and its inhibitory effects on human colon cancer / 中草药

Objective To prepare PEGylated graphene oxide nanoparticles (GO-PEG-NPs) loaded with oridonin (ORI) and investigate its inhibitory effect on human colon cancer. Methods 4-armed PEG was grafted onto GO via an amidation process and GO-PEG was characterized by IR and TGA. Then, ORI, a widely used cancer chemotherapy drug, was absorbed onto GO-PEG via blending. The encapsulation efficiency and drug loading ratio were measured by UV. The cytotoxicity of ORI-GO-PEG, GO-PEG, and free ORI on SW620 and HT29 human colon cancer cells were evaluated using MTT assay. In vivo anti-tumor activity of ORI-GO-PEG-NPs were evaluated in mice bearing SW620 tumor. Results IR and TGA data indicated that 4-armed PEG was successfully coupled with GO and UV data showed that the encapsulation efficiency and drug loading ratio were 95.81% and 48.92%, respectively. Moreover, ORI-GO-PEG-NPs showed good stability in physiological condition. The results of cytotoxicity test indicated that compared to free ORI, the ORI-GO-PEG-NPs exhibited higher cytotoxicity in SW620 and HT29 cells. Meanwhile, it was confirmed that ORI-GO-PEG- NPs could significantly inhibit the growth of SW620 tumor in vivo compared with ORI. Conclusion The obtained ORI-GO-PEG-NPs displayed excellent drug-loading capacity and better tumor inhibitory effect. These results provided the experimental basis for development of anticancer drug delivery system.

Preparation of fisetin solid dispersions / 中成药

AIM To prepare fisetin solid dispersions.METHODS Melting method and solvent method were used for the preparation of solid dispersions,respectively.With carrier type,drug-carrier ratio and stirring time as influencing factors,accumulative dissolution rate as an evaluation index,the preparation was optimized by orthogonal test on the basis of single factor experiment.The interaction between drug and carrier was investigated by Fourier transform infrared spectroscopy (FTIR),and the drug existing state was analyzed by differential scanning calorimetry (DSC).RESULTS Solvent method was more suitable for the preparation of solid dispersions.The optimal conditions were determined to be PVPK-30 as a carrier,1 ∶ 12 for drug-carrier ratio,and 30 min for stirring time,the accumulative dissolution rate reached 90.87％ within 20 min.There might be a hydrogen bond association between PVPK-30 and fisetin previously existing in amorphous or molecular state.CONCLUSION The dissolution rate of fisetin can be obviously increased after being prepared into solid dispersions.

Silver nanoparticle incorporation effect on mechanical and thermal properties of denture base acrylic resins

ABSTRACT Objective The aim of the present study was to evaluate the mechanical and thermal characteristics of two denture base acrylic resins containing silver nanoparticles (AgNPs). Material and Methods Two different acrylic denture base resins (heat-polymerized and microwave polymerized) containing 0.3, 0.8 and 1.6 wt% AgNPs were evaluated for flexural strength, elastic modulus and impact strength. The glass transition temperature (Tg) and relative heat capacity (Cp) of the samples were determined from the Differential Scanning Calorimetry (DSC) results. For statistical analysis, two-way ANOVA and Tukey-HSD tests were performed. Results Addition of 0.8% and 1.6% AgNPs in microwave-polymerized resin significantly decreased the transverse strength and elastic modulus. In terms of impact strength, the addition of AgNPs has no effect on both resin groups. Glass transition temperature (Tg) was decreased with the addition of AgNPs for both denture base resins. Conclusions The incorporation of AgNPs, generally used for antimicrobial efficiency, affected the transverse strength of the denture base acrylic resins depending on the concentration of nanoparticles. Tg was decreased with the addition of AgNPs for both denture base resins.

Calorimetric techniques applied to the thermodynamic study of interactions between proteins and polysaccharides / Técnicas calorimétricas aplicadas ao estudo termodinâmico das iterações entre proteínas e polissacarídeos

ABSTRACT: The interactions between biological macromolecules have been important for biotechnology, but further understanding is needed to maximize the utility of these interactions. Calorimetric techniques provide information regarding these interactions through the thermal energy that is produced or consumed during interactions. Notable techniques include differential scanning calorimetry, which generates a thermodynamic profile from temperature scanning, and isothermal titration calorimetry that provide the thermodynamic parameters directly related to the interaction. This review described how calorimetric techniques can be used to study interactions between proteins and polysaccharides, and provided valuable insight into the thermodynamics of their interaction.

RESUMO: As interações entre macromoléculas biológicas têm tido importante aplicação na biotecnologia, mas, para sua devida utilização, estudos mais detalhados são necessários. As técnicas calorimétricas permitem estudá-las ao serem capazes de fornecer informações referentes a essas interações através da energia térmica que é gerada ou absorvida durante o processo de interação. Dentre as técnicas que mais se destacam estão a Calorimetria Exploratória Diferencial, que é capaz de fornecer um perfil termodinâmico a partir de uma varredura de temperatura, e a Calorimetria de Titulação Isotérmica, que fornece parâmetros termodinâmicos diretamente relacionados ao processo de interação. Nesta revisão, descrevemos como essas técnicas calorimétricas podem ser efetivamente aplicadas no estudo das interações entre proteínas e polissacarídeos, com o propósito de obter informações valiosas sobre a termodinâmica da interação.

Nano-Crystalline Cellulose as a Novel Tablet Excipient for Improving Solubility and Dissolution of Meloxicam.

This study explored the effect of nano-crystalline cellulose (NCC) on Meloxicam (MX) solid dispersion (SD) prepared by co-grinding technique compared to micro-crystalline cellulose (MCC) in presence of lactose. MX-tablets were prepared by direct compression of different co-ground SDs or physical mixtures. The solubility, dissolution, SEM and DSC of different preparations were studied. Flow-through cell apparatus (FTC) was used to study the dissolution of MX from tablets at pH 7.4. Generally, the results revealed that increasing NCC loadings showed a direct increase in both the solubility and dissolution of MX. MCC did not improve either the solubility or the dissolution of MX in the physical mixture, while, co-grinding dramatically decreased the dissolution rate of MX. It was interesting to find that grinding of MX-powder alone or in a mixture with lactose highly increased MX solubility and dissolution. SEM as well as DSC were found to be very good tools, without a single exception, to describe the observed solubility and dissolution of MX in these proposed preparations. SEM-images showed the particle size reduction upon grinding or co-grinding techniques. While DSC-data proved that the crystalline structure of MX has been changed to an amorphous state.

Monitoring real time polymorphic transformation of sulfanilamide by diffuse reflectance visible spectroscopy$ / 药物分析学报

This study investigated the development of a novel approach to surface characterization of drug poly-morphism and the extension of the capabilities of this method to perform ‘real time’ in situ measure-ments. This was achieved using diffuse reflectance visible (DRV) spectroscopy and dye deposition, using the pH sensitive dye, thymol blue (TB). Two polymorphs, SFN-β and SFN-γ, of the drug substance sul-fanilamide (SFN) were examined. The interaction of adsorbed dye with polymorphs showed different behavior, and thus reported different DRV spectra. Consideration of the acid/base properties of the morphological forms of the drug molecule provided a rationalization of the mechanism of differential coloration by indicator dyes. The kinetics of the polymorphic transformation of SFN polymorphs was monitored using treatment with TB dye and DRV spectroscopy. The thermally-induced transformation fitted a first-order solid-state kinetic model (R2 ? 0.992), giving a rate constant of 2.43 ? 10 ? 2 s ? 1.

Determination of Purity and Uncertainty Evaluation of Bisacodyl by Differential Scanning Calorimetry / 中国药房

OBJECTIVE:To establish the purity determination of bisacodyl by differential scanning calorimetry(DSC)and the valuation of uncertainty. METHODS:DSC was conducted to detect the purity of bisacodyl and determine the optimal testing condi-tions. According to related standards,indium enthalpy change values,measurement repeatability,weighing process,instrument tem-perature deviation and system software deviation were systematically analyzed. The results were verified by HPLC. RESULTS:When the fiducial probability P was 0.95,the standard value and uncertainty of content of bisacodyl was (99.88 ± 0.06)% mea-sured by DSC. Weighing process,instrument temperature deviation and system software deviation had great effects on the total un-certainty. The result of HPLC and DSC were the same. CONCLUSIONS:The established DSC can quickly and accurately determine the chemical purity of bisacodyl. The uncertainty evaluation is reliable. Regularly calibrated and verificated equipment and strict con-trol of the weighing process will help to improve the accuracy measured by DSC;and it provides a new analysis method for the de-termination of purity of bisacodyl.

Evaluación de citrato de calcio y magnesio obtenido de dolomitas cubanas / Evaluation of calcium and magnesium citrate from Cuban dolomite

INTRODUCTION: calcium and magnesium salts are used as nutritional supplements obtained from natural sources such as dolomite, which is a double complex of calcium and magnesium carbonate. In search of a calcium raw material with greater bioavailability, a process of obtaining calcium and magnesium citrate salt from dolomite deposits was developed. OBJECTIVE: to evaluate calcium and magnesium citrate from dolomite. METHODS: chemical and technological analysis, Powder X-ray Diffractometry attenuated total reflection-Fourier transform infrared spectrometry (ATR-FTIR), differential scanning calorimetry and thermogravimetric analysis were all used. RESULTS: the chemical analysis confirmed the existence of calcium (over 10 percent), and of magnesium (4.5 and 5 percent) whereas citric acid content was under 3 percent, The levels of toxic metals were below the maximum allowable limits for pharmaceutical products. The density values were below those of the dolomite, with high porosity and flow deficit. The X-ray diffractomery indicated that dolomite was transformed into calcium and magnesium citrate salts whereas, the infrared spectra showed the presence of characteristic COO¯, -OH and -CH2 groups of citrates. The differential scanning calorimetry showed that salt had three endothermic peaks at 101.7 ºC, 167.1 ºC y 194.6 ºC and on the other hand, termogravimetry analysis confirmed that 30.9 percent of the total mass is lost at temperatures lower than 295 ºC..CONCLUSIONS: the presence of calcium and magnesium citrate salt is corroborated(AU)

INTRODUCCIÓN: las sales de calcio y magnesio son utilizadas como suplementos nutricionales y se obtienen a partir de fuentes naturales, dentro de las cuales se encuentra la dolomita, que es un complejo doble de carbonato de calcio y magnesio. En la búsqueda de una materia prima de calcio con mayor biodisponibilidad, ha sido desarrollado un proceso de obtención de sales de citrato de calcio y magnesio a partir de dolomitas. OBJETIVO: evaluar el citrato de calcio y magnesio obtenido a partir de dolomita. MÉTODOS: se emplearon métodos de análisis químicos y tecnológicos, difracción de rayos X, reflexión total atenuada en el infrarrojo medio con transformada de Fourier, calorimetría diferencial de barrido y análisis termogravimétrico. RESULTADOS: los resultados del análisis químico demostraron la presencia de calcio (superior al 10 por ciento) y magnesio (entre 4,5 y 5 por ciento), mientras que el contenido de ácido cítrico fue menor al 3 por ciento. Los niveles de metales tóxicos estaban por debajo de los límites máximos permisibles para productos farmacéuticos. Los valores de densidades fueron inferiores a las densidades de la dolomita, con la presencia de un elevado porcentaje de porosidad y deficiente flujo. El análisis por difracción de rayos X demostró que la dolomita fue transformada en sales de citrato de calcio y magnesio, mientras que los espectros infrarrojos mostraron que las principales absorciones se corresponden con las de los grupos COO¯, -OH y -CH2, características todas de citratos. Los estudios por calorimetría diferencial de barrido indicaron que la sal presentaba tres transiciones endotérmicas a 101,7 ºC, 167,1 ºC y 194,6 ºC, y el análisis termogravimétrico corroboró que a temperaturas menores de 295 ºC ocurre una pérdida de masa que representa el 30,9 por ciento de la masa total. CONCLUSIONES: se corrobora la presencia de sal de citrato de calcio y magnesio(AU)

Evaluation and study of mebendazole polymorphs present in raw materials and tablets available in the Brazilian pharmaceutical market.

The dissolution of a drug can be compromised by the presence of different polymorphs, which may have different solubilities. Importantly, the pharmacopoeiamonographs,usually not have tests for the characterization of these polymorphic forms of a drug. Was performed a study of polymorphic forms of mebendazole present in raw materials and also pills available in the Brazilian pharmaceutical market through the techniques of infrared (FTIR), differential scanning calorimetry (DSC), dissolution , solubility and X-ray diffraction pattern (XRPD). Through the analysis of FTIR and DSC curves showed that there are three main polymorphic forms of mebendazole present in raw materials and tablets that compound. The data obtained in the dissolution and solubility tests showed that Form A is less soluble than Form B which is less soluble than the C form, when using a dissolution medium without added surfactant. It has been found that in some tablets mebendazole there is a mixture of polymorphic forms, and that the raw materials present two major polymorphic forms. Then it is suggested the need of quality control regarding the type of polymorph used in the production of mebendazole tablets to ensure greater therapeutic efficacy.