Determination of the p-monochlorophenol residue in the calcium hydroxide plus p-monochlorophenol combination used as an intracanal dressing in pulpless teeth of dogs with induced chronic periapical lesion

To determine the presence of p-monochlorophenol in the calcium hydroxide (Calen) + p-monochlorophenol combination after its use as intracanal dressing, periapical lesions were induced in 60 root canals of upper and lower premolars of four dogs, After biomechanical preparation, the root canals received the intracanal medication, which was removed from the apical third after 2, 4, 7, and 14 days for chemical analysis by spectrophotometry, the results showed a p-monochlorophenol loss of approximately 50.0% in the dressing after 48 h, with no further significant loss after longer periods of times, p-Monochlorophenol was still present in the medication after 14 days.

Desenvolvimento de sistema de análise para valerato de estradiol baseado em polímeros biomiméticos

Abstracts : The development of analytic methods more selective and sensitive is of great importance for a better quality in the determination of chemical species, therefore increasing the reliability of the results. In this way, the optimization of separation/concentration is still necessary. The use of Molecularly Imprinted Polymers - MIPs have demonstrated to be an efficient tool of analysis with a great potential in minimizing limitations of separation/concentration techniques traditionally employed. In general, the MIPs are obtained by polymerization in the presence of a template to be imprinted so that a polymeric skeleton is formed around the future analyte. In the present work, the template used is Estradiol Valerate (EV), compound used in the hormone replacement therapy (HRT) during climacteric. After the polymerization in bulk and in an anaerobic environment using MAA, EGDMA, AIBN, acetonitrile and VE, the obtained MIP was powdered, sifted (<120 μm) and placed in a soxhlet system containing ethanol at 60 °C, in order to remove the imprinted molecule through six successive washes in periods of 24 hours. The water used in the washings was analyzed using HPLC and spectrophotometry UV/Vis. Then, the obtained MIP was dried at room temperature and 150 mg was inset in SPE cartridges in order to evaluate the polymer's efficiency in the analyte pre-concentration and extraction. To do so, 100,0 mL of VE standard solution (2mg L-1) were pre-concentrated at 4,0 mL min-1 and eluted with 10,0 mL ethanol at 1,0 mL min-1, obtaining recoveries of 53%. Additionally, a NIP (non-imprinting polymer) was prepared to compare the obtained results, in which the recovery was 80%. In the same way, studies were conducted using commercial Strata™-X cartridges, obtaining 53% recovery. Since, the results did not reflect that than was expected, in relation with the MIP efficiency in the recovery, a computational ...

Chromatic stability of acrylic resins of artificial eyes submitted to the accelerated aging and polishing

Esthetics and durability of materials used to fabricate artificial eyes has been an important issue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. OBJECTIVE: This study assessed the color stability of acrylic resins used to fabricate sclera in three basic shades (N1, N2 and N3) when subjected to accelerated aging, mechanical and chemical polishing. MATERIAL AND METHODS: Specimens of each resin were fabricated and submitted to mechanical and chemical polishing. Chromatic analysis was performed before and after accelerated aging through ultraviolet reflection spectrophotometry. RESULTS: All specimens revealed color alteration following polishing and accelerated aging. The resins presented statistically significant chromatic alteration (p<0.01) between the periods of 252 and 1008 h. CONCLUSIONS: Both polishing methods presented no significant difference between the values of color derivatives of resins.

Spectrophotometric evaluation of color changes of esthetic brackets stored in potentially staining solutions

The purpose of this study was to evaluate, in vitro, the chromatic behavior of esthetic brackets stored in potentially staining solutions. The sample were divided into four groups according to the commercial brand and stored in four different solutions (distilled water, cola soda, coffee and mouthrinse) at 37°C for 14 days. Possible color changes measured according to the CIE L*a*b* color system with a spectrophotometer at five intervals of time after storage. The statistical analysis was carried out using ANOVA to 1%, Tukey's tests and decomposition of interactions with a significance level of 5%.The color changes were dependent on the solution, storage time and the brand of brackets. The largest color changes were observed in the G3, followed by G2, G1/G4. The esthetic brackets do not present satisfactory and stable chromatic behavior.

Avaliação da termociclagem sobre a estabilidade de cor de diferentes matizes de resina composta

The objective was to evaluate the effect of thermocycling on the color variation of three different composite resins . We studied was Resin Enamel on 3 levels : ( Esthetic X , Opallis and Venus ) ; Resin Dentin in three levels : ( Esthetic X , Opallis and Venus ) and Thermocycling on level 1 : ( 3,000 cycles ) ; variable was the change of color gauged by spectrophotometry . 60 specimens , subdivided into 6 groups were made : GI - Esthetic X Enamel ; GII - Esthetic X dentin ; GIII - Opallis Enamel ; GIV - Opallis dentin ; GV - Enamel and GVI Venus - Venus dentin . The specimens were prepared with a matrix to standardize samples . The inserts of incrementally resins and polymerized with a halogen light Ultralux unit ( Dabi Atlante , Brazil ) with a power of 450mW / cm ² . After fabrication , underwent color reading with a UV Visible Spectrophotometer reflection , UV -2450 ( Shimadzu , Kyoto , Japan ) , with the changes calculated by the system CIE L * a * b * . Then isolates were stored in artificial saliva at 35 ° C ± 2 ° C during 3 months containers being subjected to the effects of thermal cycling for 3000 cycles over the range of 5C to 55C . Again subjected to chromatic evaluation. For the analysis of the results of color change of the studied resins was applied ANOVA two factors at 5 % . The results showed a statistically equal resins enamel GI and GV ( p = 0.79 ) ; the same was not observed for GI and G III resins , where the color change was higher for resin G III ( p = 0.0000002 ) . The same was observed between G III and GV , where the resin enamel G III showed a statistically superior to the color change ( p = 0.0000005 ) Average . Resins to dentin was there a statistical equality between the materials studied . We conclude that the resins studied change in color and resin enamel G III was the most suffered major color changes after aging by thermocycling .

Ciclamato de sódio em refrigerantes de baixa caloria

Sodium cyclamate contents in the widely consumed low calorie soft drinks were determined. Low calorie soft drinks made from cola, guarana, orange, lemon and grape were analyzed following the technique described by Sjörberg and Alanko (1987), with some modifications. The methodology recovery assays were carried out at three spiked levels, and the average recovery of 92.5% and 110.3% were found in cola and guarana, respectively; and the relative standard deviation was of 3.7%. The average sodium cyclamate contents ranged from 27.1 ± 1.1 (cola A) to 127.3 ± 1.5 mg.100 mL-1 (lemon B), indicating that the acceptable daily intake of the sweetener can be easily exceeded after drinking low calorie beverages. All of the analyzed low calorie soft drinks showed sodium cyclamate contents higher than those stated on the label, ranging from 12.9% (cola A) to 19.0% (lemon B). Among 18 low calorie soft drinks analyzed, only four showed the average sodium cyclamate contents in accordance with the maximum limit permitted by Brazilian legislation, that is 40 mg.100 mL-1 of beverage; and in other samples the sweetener exceeded ranging from 74.8% (orange) to 218.3% (lemon B) above of the limit permitted.

Physico-chemical characterization and analytical development for sodium azumolene, a potential drug designed to fight malignant hyperthermia

Sodium azumolene is a drug designed to fight Malignant Hyperthermia (MH), which is characterized by genetic predisposition and triggered by the use of inhalational anesthetics. This drug is shown as a water-soluble analogue of dantrolene sodium, 30-folds more water soluble, which gives advantages for its emergency use. To our knowledge there is no analytical method for sodium zaumolene raw material or dosage form published so far. The objective of the present investigation was to develop and validate analytical methods to achieve sodium azumolene chemical identification and quantification. The sodium azumolene was characterized regarding its thermal behavior, by differential thermal analysis and thermogravimetric analysis; Visible, UV and infrared absorption. To accurately assess the sodium Azumolene content three different analytical methods (visible and UV spectrophotometry and high performance liquid chromatography) were developed and validated. All methods showed to be linear, accurate, precise and reliable. Azumolene has shown to be equipotent to dantrolene in the treatment and prevention of an MH crisis and the great advantage compared to dantrolene is better water solubility. This study has characterized the sodium azumolene and presents new analytical methods which have not been reported so far.

Development and validation of first derivative spectrophotometric method for quantification of darunavir in tablets

Aims: Darunavir is widely used in HIV/AIDS therapy. It is a HIV protease inhibitor that has excellent efficacy against the virus. The aim of this study is to develop and validate an analytical method fast and free of interferences for determination of darunavir ethanolate as raw material and tablet dosage form. Methodology: As the formulation excipients show high interference in darunavir determination by a direct UV absorption measurement a derivative spectrophotometry was applied. A selective, easy and fast method was achieved employing simple and cheap instrumentation by using first-order derivative spectrophotometry. Results: The first-derivation of spectrum of the drug measured between 200 and 400 nm allowed identification of the analyte and showed absence of placebo interference. The assay was based on the absorbance at 276nm. The linear concentration range was established from 11 to 21 μg/mL. The intra-day and inter-day precision expressed as RSD was 0.06% and 3.75% respectively with mean recovery of 99.84%. Conclusion: The proposed analytical method is able to quantify darunavir as raw material and tablets and can be used routinely by any laboratory applying a spectrophotometer with a derivative accessory. The great difference of the method proposed here is that it proves to be free of placebo interferences as well as simple, fast and low cost.

Spectrophotometric determination of ciprofloxacin hydrochloride in ophthalmic solution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Doxycycline hyclate: a review of properties, applications and analytical methods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A first-derivative spectrophotometric method for the determination of ciprofloxacin hydrochloride in ophthalmic solution

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do desuso e da deficiência de estrógeno sobre a microarquitetura óssea e suas propriedades biomecânicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Métodos de coleta de deposição para ensaios de deriva em aplicações aéreas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acidose ruminal subaguda em ovinos Santa Inês: estudo clínico, laboratorial e avaliação da laminite por termografia infravermelha e radiologia digital

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo hidrodinâmico quali-quantitativo de uma unidade de flotação por ar dissolvido (FAD): o efeito do dispositivo de coleta de água flotada

The main article aim was to investigate the collecting system of a dissolved air flotation (DAF) unit in pilot scale. Referring to the collecting system position, two options were analyzed: (i) top manifold and (ii) bottom manifold, pipes or plates. Qualitative and quantitative essays were performed, as image and stimulusresponse tests, respectively. The results of the essays standardized were adjusted by N-continuous stirred tank reactors in series and theoretical models of dispersion (low and high). The bottom manifold (plates with orifices) was more appropriate. The results pointed out that the N-continuous stirred tank reactors in series model was more adequate to describe the hydrodynamic behavior of the DAF unit.