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1.
Respir Res ; 23(1): 308, 2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36369209

RESUMO

Idiopathic pulmonary fibrosis, the archetype of pulmonary fibrosis (PF), is a chronic lung disease of a poor prognosis, characterized by progressively worsening of lung function. Although histology is still the gold standard for PF assessment in preclinical practice, histological data typically involve less than 1% of total lung volume and are not amenable to longitudinal studies. A miniaturized version of computed tomography (µCT) has been introduced to radiologically examine lung in preclinical murine models of PF. The linear relationship between X-ray attenuation and tissue density allows lung densitometry on total lung volume. However, the huge density changes caused by PF usually require manual segmentation by trained operators, limiting µCT deployment in preclinical routine. Deep learning approaches have achieved state-of-the-art performance in medical image segmentation. In this work, we propose a fully automated deep learning approach to segment right and left lung on µCT imaging and subsequently derive lung densitometry. Our pipeline first employs a convolutional network (CNN) for pre-processing at low-resolution and then a 2.5D CNN for higher-resolution segmentation, combining computational advantage of 2D and ability to address 3D spatial coherence without compromising accuracy. Finally, lungs are divided into compartments based on air content assessed by density. We validated this pipeline on 72 mice with different grades of PF, achieving a Dice score of 0.967 on test set. Our tests demonstrate that this automated tool allows for rapid and comprehensive analysis of µCT scans of PF murine models, thus laying the ground for its wider exploitation in preclinical settings.


Assuntos
Aprendizado Profundo , Fibrose Pulmonar , Animais , Camundongos , Fibrose Pulmonar/diagnóstico por imagem , Microtomografia por Raio-X , Modelos Animais de Doenças , Densitometria
2.
Reumatol. clín. (Barc.) ; 18(8): 459-463, Oct. 2022. tab
Artigo em Espanhol | IBECS | ID: ibc-210199

RESUMO

Objetivo: Analizar determinantes de mortalidad a 15años en relación con la salud ósea en una población de mayores de 60años y físicamente activos. Métodos: Estudio longitudinal prospectivo. A los 15años de participar en un programa de envejecimiento activo, y de los que se disponía de datos de salud ósea, se contactó telefónicamente con los participantes para constatar el estado vital y conocer si en ese intervalo de tiempo habían tenido alguna fractura, y para determinar la asociación entre la puntuación basal del FRAX, los datos densitométricos y la mortalidad al cabo del tiempo.Resultados: Se incluyeron 561 individuos mayores de 60años, de los que el 82% eran mujeres. Solo se encontraron diferencias en las características basales entre el grupo que falleció a los 15años y el grupo que siguió con vida en los datos densitométricos y en los valores del FRAX, así como en el antecedente de algún tipo de fractura. Las únicas variables que se relacionaron con el riesgo de mortalidad fueron los datos basales del T-score densitométricos (OR=0,50; p<0,001) y el antecedente de fractura en cualquier localización (OR=2,44; p<0,033).Conclusiones: El valor de la densidad mineral ósea podría considerarse como un biomarcador útil para calcular el riesgo de mortalidad en mayores de 60años con una vida físicamente activa.(AU)


Objective: To analyse determinants of mortality at 15years in a population over 60years of age and physically active. Methods: This is a prospective longitudinal study. After 15years of participating in an active aging programme, participants were contacted by telephone to verify their state of health and to determine whether in that time they had had any fractures. Results: A total of 561 individuals over 60years of age were included, 82% of whom were women. Only differences in densitometric data, FRAX values and history of previous fracture at baseline characteristics were found between the group that died at 15years and the group that remained alive. The only variables that were related to mortality risk were the basal data of the densitometric T-score (OR=.50, P<.001) and history of fracture in any location (OR=2.44, P<.033). Conclusions: The value of bone mineral density could be considered as a useful biomarker to calculate the risk of mortality in people over 60years old with a physically active lifestyle.(AU)


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Indicadores de Morbimortalidade , Mortalidade , Envelhecimento , Entrevistas como Assunto , Densitometria , Osteoporose , Densidade Óssea , Reumatologia , Espanha/epidemiologia , Estudos Longitudinais , Estudos Prospectivos
3.
Biomed Tech (Berl) ; 67(6): 503-512, 2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36102674

RESUMO

Skin thickness, including the adipose layer, which varies from individual to individual, affects the bone density measurement using light. In this study, we proposed a method to measure skin thickness using light and to correct the bias caused by differences in skin thickness and verified the proposed method by experiments using a phantom. We measured simulated skin of different thicknesses and bovine trabecular bone of different bone mineral densities (BMDs) using an optical system consisting of lasers of 850 and 515 nm wavelengths, lenses, and slits. Although the slope of the light intensity distribution formed on the surface of the material when irradiated by the 850 nm laser is affected by the thickness of the skin phantom. The difference of the intensity distribution peaks (δy) between the 850 and 515 nm lasers was strongly correlated with the thickness of the skin phantom. The coefficient of determination between the measurements and the BMD was improved by correcting the 850 nm laser measurements with δy. This result suggests that the method is applicable to optical bone densitometry, which is insensitive to differences in skin thickness.


Assuntos
Densidade Óssea , Pele , Bovinos , Animais , Imagens de Fantasmas , Luz , Densitometria/métodos
4.
Medicine (Baltimore) ; 101(33): e29860, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35984137

RESUMO

Long-term glucocorticoids administration inhibits bone mineralization and has a negative impact on basic cellular mechanisms that are critical in the development and maintenance of bone strength. Steroids can cause osteoporosis in children and have a negative impact on bone mineral content (BMC) and bone mineral density (BMD). We aim to determine the BMD of children with idiopathic nephrotic syndrome (INS) who are on corticosteroids therapy. This cross-sectional study included 90 patients on corticosteroids therapy and 50 apparently healthy age and sex-matched children served as a control group. Renal functions, bone biochemistry, and parathyroid hormone (PTH) were measured in patients and controls. BMD was measured at the lumbar spinal region (L2-L4) using Dual-energy X-ray absorptiometry (DEXA) scan in both patients and controls groups. Serum PTH, phosphorous, and alkaline phosphatase levels were significantly higher in patients than in controls. There was a statistically significant reduction in blood calcium levels in patients compared to controls. Osteopenia was diagnosed by DEXA scan in 24 patients (26.7%) and osteoporosis in 12 patients (13.3 %). There was a statistically significant decline in BMD-z score, BMD, and BMC in patients compared to the healthy group. Patients with INS on corticosteroids treatment have a lower BMD than their peers. Pediatric INS patients had a high prevalence of osteopenia and osteoporosis as measured by DEXA. Steroid therapy has a deleterious impact on bone mineralization in children with INS.


Assuntos
Doenças Ósseas Metabólicas , Nefrose Lipoide , Síndrome Nefrótica , Osteoporose , Absorciometria de Fóton , Densidade Óssea , Doenças Ósseas Metabólicas/induzido quimicamente , Doenças Ósseas Metabólicas/diagnóstico por imagem , Doenças Ósseas Metabólicas/epidemiologia , Criança , Estudos Transversais , Densitometria , Humanos , Nefrose Lipoide/complicações , Síndrome Nefrótica/complicações , Síndrome Nefrótica/tratamento farmacológico , Osteoporose/induzido quimicamente , Osteoporose/diagnóstico por imagem , Osteoporose/epidemiologia , Hormônio Paratireóideo , Esteroides
5.
Phys Med ; 100: 142-152, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35839667

RESUMO

PURPOSE: To develop and validate an automated segmentation tool for COVID-19 lung CTs. To combine it with densitometry information in identifying Aerated, Intermediate and Consolidated Volumes in admission (CT1) and follow up CT (CT3). MATERIALS AND METHODS: An Atlas was trained on manually segmented CT1 of 250 patients and validated on 10 CT1 of the training group, 10 new CT1 and 10 CT3, by comparing DICE index between automatic (AUTO), automatic-corrected (AUTOMAN) and manual (MAN) contours. A previously developed automatic method was applied on HU lung density histograms to quantify Aerated, Intermediate and Consolidated Volumes. Volumes of subregions in validation CT1 and CT3 were quantified for each method. RESULTS: In validation CT1/CT3, manual correction of automatic contours was not necessary in 40% of cases. Mean DICE values for both lungs were 0.94 for AUTOVsMAN and 0.96 for AUTOMANVsMAN. Differences between Aerated and Intermediate Volumes quantified with AUTOVsMAN contours were always < 6%. Consolidated Volumes showed larger differences (mean: -95 ± 72 cc). If considering AUTOMANVsMAN volumes, differences got further smaller for Aerated and Intermediate, and were drastically reduced for consolidated Volumes (mean: -36 ± 25 cc). The average time for manual correction of automatic lungs contours on CT1 was 5 ± 2 min. CONCLUSIONS: An Atlas for automatic segmentation of lungs in COVID-19 patients was developed and validated. Combined with a previously developed method for lung densitometry characterization, it provides a fast, operator-independent way to extract relevant quantitative parameters with minimal manual intervention.


Assuntos
COVID-19 , COVID-19/diagnóstico por imagem , Densitometria , Humanos , Estudos Longitudinais , Pulmão/diagnóstico por imagem
6.
PLoS One ; 17(7): e0271135, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35797398

RESUMO

The purpose of this study is to evaluate the quantitative diagnostic performance of computed tomography (CT) densitometry in pediatric patients with bronchiolitis obliterans (BO). We measured the mean lung density (MLD) and represented the difference of MLD in inspiratory and expiratory phases (MLDD), the ratio of the MLD (E/I MLD), and the relative volume percentage of lung density at 50-Hounsfield unit (HU) interval threshold (E600 to E950). We calculated the sensitivity, specificity, and diagnostic accuracy of the lung density indices for the diagnosis of BO. A total of 81 patients, including 51 patients with BO and 30 controls, were included in this study. In the BO patients, expiratory (EXP) MLD and MLDD were significantly lower, and E/I MLD and expiratory low attenuation areas below the threshold of -850 HU to -950 HU (E850, E900, and E950) were statistically significantly higher than controls. Multivariate logistic regression analysis showed that MLDD (odds ratio [OR] = 0.98, p < .001), E/I MLD (OR = 1.39, p < .001), and E850 to E950 were significant densitometry parameters for BO diagnosis. In a receiver-operating characteristic analysis, E900 (cutoff, 1.4%; AUC = 0.920), E/I MLD (cutoff, 0.87; AUC = 0.887), and MLDD (cutoff, 109 HU; AUC = 0.867) showed high accuracy for the diagnosis of BO. In conclusion, the lung CT densitometry can serve as a quantitative marker providing additional indications of expiratory airflow limitation in pediatric patients with BO.


Assuntos
Bronquiolite Obliterante , Pneumopatias , Bronquiolite Obliterante/diagnóstico por imagem , Criança , Densitometria , Humanos , Pulmão/diagnóstico por imagem , Testes de Função Respiratória/métodos , Tomografia Computadorizada por Raios X/métodos
7.
Photodiagnosis Photodyn Ther ; 39: 102990, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35792251

RESUMO

BACKGROUND: This study aimed to investigate the presence of subclinical inflammation in the eye by examining corneal and lens changes in children with familial Mediterranean fever (FMF) and provide the regulation for follow-up and treatment protocols according to the presence of signs of inflammation. DESIGN: This is a cross-sectional, case-control study. METHODS: Topographic parameters and corneal and lens densitometry of 48 patients with FMF (10.12 ± 3.84 years [range: 5-19 years]) and 33 healthy volunteers (10.94 ± 3.78 years [range: 5-19 years]; p > 0.05) were evaluated with a Scheimpflug camera. For corneal densitometric measurements, the cornea was divided into four concentric radial zones and anterior, central, and posterior layers according to corneal thickness. The mean densitometry value for the crystalline lens was calculated in three zones around the center of the pupil. RESULTS: Corneal light backscattering in all layers and zones of the cornea were similar between the patient and control groups. Lens densitometry values in the three zones did not differ between the two groups (p > 0.05). Maximum lens densitometry values were found to be significantly higher in the patient group (22.14 vs 19.11; p = 0.011). CONCLUSION: Monitoring the cornea and lens density in patients with FMF using Pentacam may help to show the presence of subclinical inflammation and regulate the follow-up and treatment protocols. Larger sample sizes and prospective design studies are needed to reach more conclusive results.


Assuntos
Febre Familiar do Mediterrâneo , Cristalino , Fotoquimioterapia , Estudos de Casos e Controles , Criança , Córnea/diagnóstico por imagem , Estudos Transversais , Densitometria/métodos , Febre Familiar do Mediterrâneo/complicações , Febre Familiar do Mediterrâneo/diagnóstico , Humanos , Inflamação , Cristalino/diagnóstico por imagem , Fotoquimioterapia/métodos
9.
Clin Nucl Med ; 47(8): e568-e569, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35797635

RESUMO

ABSTRACT: We report a rare case of type 3 Gaucher disease presenting with calcified mesenteric lymph nodes that interfere with bone mineral densitometric measurements.


Assuntos
Doença de Gaucher , Linfadenopatia , Densidade Óssea , Densitometria , Doença de Gaucher/complicações , Doença de Gaucher/diagnóstico por imagem , Humanos , Minerais
10.
Farm. comunitarios (Internet) ; 14(Supl 1): 1, junio 2022. graf, ilus
Artigo em Espanhol | IBECS | ID: ibc-209306

RESUMO

JUSTIFICACIÓN: debido a los cambios demográficos derivados del envejecimiento de la población y el aumento de pacientes con enfermedades crónicas en el mundo, la osteoporosis se ha convertido en una enfermedad prevalente y un problema de salud pública, con importantes repercusiones debido a la morbilidad y morbimortalidad que conlleva, y a los gastos directos e indirectos que genera. Si no se interviene desde la prevención, tratamiento precoz y adherencia al mismo en la práctica clínica, el número de pacientes que sufrirán osteoporosis y sus consecuencias irá en aumento. OBJETIVOS: formar al farmacéutico comunitario en educación sanitaria para la población de más de 50 años susceptible de sufrir enfermedad osteoporótica. Establecer un conjunto de recomendaciones basadas en la evidencia científica acerca de la atención farmacéutica en la enfermedad osteoporótica. MATERIAL Y MÉTODOS: estudio cuasiexperimental con intervención formativa y evaluación antes/después. Procedimiento. Se imparte el taller de forma presencial en quince ciudades con una duración de 45 minutos, eligiendo el farmacéutico horario de mañana o de tarde. Éste consta de una parte teórica y un caso práctico dividido en tres fases de seguimiento. Los asistentes responden a cinco preguntas de impacto antes y después de asistir al taller y se comparan las respuestas.RESULTADOS/ DISCUSIÓN: un 15% más de los asistentes conoce tras el taller que el problema fundamental de la enfermedad osteoporótica es la fractura por fragilidad. La mayoría de asistentes ya sabían antes del taller que se trata de una enfermedad más frecuente en mujeres (92,3%) y que el tratamiento farmacológico más habitual son los bifosfonatos (87,6%). Además, tras asistir al taller, el 14% de los asistentes mejoraron el conocimiento de los factores de riesgo más importantes y el 16% aprendió que la técnica validada para la fragilidad ósea es la densitometría central. (AU)


Assuntos
Humanos , Osteoporose , Farmacêuticos , Densitometria , Doença Crônica , Farmácia
12.
Ophthalmic Physiol Opt ; 42(5): 1032-1037, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35708180

RESUMO

PURPOSE: To investigate whether Pentacam densitometry readings are affected by corneal tilt. METHODS: In a prospective study, the right eyes of 86 healthy participants aged 42.8 ± 20.0 years (range 18-79 years) were imaged using Scheimpflug tomography. Elevation maps were exported to calculate corneal tilt using custom-made software, and densitometry readings were acquired directly from the corneal densitometry analysis add-on to the standard software Oculus Pentacam HR. Simple mediation analysis was applied to study age as a confounding factor in the correlation between corneal tilt and corneal densitometry. RESULTS: Corneal tilt and corneal densitometry are not independent from one another because age is significantly correlated with both corneal tilt (r = 0.50, p < 0.001) and corneal densitometry (r = 0.91, p < 0.001). Only 3.8% of the correlation between tilt and densitometry operates directly, while the remaining 96.2% depends on age. CONCLUSIONS: Corneal tilt plays a role in corneal densitometry readings, even though the interaction is strongly influenced by age. Age is a well-known factor in densitometry readings that should be taken into consideration when interpreting Scheimpflug densitometry.


Assuntos
Córnea , Topografia da Córnea/métodos , Densitometria/métodos , Voluntários Saudáveis , Humanos , Estudos Prospectivos
14.
BMC Ophthalmol ; 22(1): 286, 2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35764952

RESUMO

PURPOSE: To evaluate corneal densitometry after allogeneic corneal small-incision intrastromal lenticule implantation (SILI) for hyperopia. METHODS: A retrospective study. Thirty-one hyperopic eyes of 24 patients who underwent SILI were enrolled in this study. Examinations took place preoperatively and 1 week, 1 month, 3 months, and 6 months postoperatively. Corneal densitometry (CD) from different concentric radial zones (0-2, 2-6, and 6-10 mm annulus) and layers (anterior, central, and posterior) were obtained using Scheimpflug imaging. The association between CD changes and the uncorrected distance visual acuity (UDVA), spherical equivalent (SE), central corneal thickness (CCT) and K value were examined. RESULTS: No serious intraoperative complications occurred during SILI. The mean total CD increased postoperatively compared to preoperatively (P < 0.01). However, no significant differences were found among the four subsequent follow-up time points (P > 0.05). At 6 months postoperatively, the CD values showed an increase of 2.71 ± 2.52, 2.23 ± 2.25, and 1.87 ± 2.46 at the 0-2, 2-6, and 6-10 mm annuli, respectively (all at P < 0.01). The anterior 120 µm displayed the highest densitometry before and after surgery (all at P < 0.01). No significant increase was found within the posterior 60 µm of the cornea (P > 0.05). No correlation was found between the CD and relevant parameters(all at P > 0.05). CONCLUSIONS: SILI resulted in an increase in CD within the surgically altered area, however such change has no significant correlation with visual outcomes.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Hiperopia , Córnea/cirurgia , Substância Própria/cirurgia , Topografia da Córnea , Densitometria , Humanos , Hiperopia/cirurgia , Estudos Retrospectivos
15.
J Biomed Opt ; 27(5)2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35585663

RESUMO

SIGNIFICANCE: To achieve early detection of osteoporosis, a simple bone densitometry method using optics was proposed. However, individual differences in soft tissue structure and optical properties can cause errors in quantitative bone densitometry. Therefore, developing optical bone densitometry that is robust to soft tissue variations is important for the early detection of osteoporosis. AIM: The purpose of this study was to develop an optical bone densitometer that is insensitive to soft tissue, using Monte Carlo simulation and machine learning techniques, and to verify its feasibility. APPROACH: We propose a method to measure spatially resolved diffuse light from three directions of the biological tissue model and used machine learning techniques to predict bone density from these data. The three directions are backward, forward, and lateral to the direction of ballistic light irradiation. The method was validated using Monte Carlo simulations using synthetic biological tissue models with 1211 different random structural and optical properties. RESULTS: The results were computed after a 10-fold cross-validation. From the simulated optical data, the machine learning model predicted bone density with a coefficient of determination of 0.760. CONCLUSIONS: The optical bone densitometry method proposed in this study was found to be robust against individual differences in soft tissue.


Assuntos
Aprendizado de Máquina , Osteoporose , Simulação por Computador , Densitometria , Humanos , Método de Monte Carlo
16.
Indian J Ophthalmol ; 70(5): 1556-1563, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35502026

RESUMO

Purpose: To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers. Methods: This is a cross-sectional, case-control study. The AS diagnosis was made clinically. Forty-five eyes of 45 patients with AS and 38 eyes of 38 age-matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant. Results: The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = -1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10-12 mm) (r = 0.334 and P = 0.025). Conclusion: The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea's paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS.


Assuntos
Arco Senil , Idoso , Arco Senil/diagnóstico , Estudos de Casos e Controles , Córnea , Estudos Transversais , Densitometria , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Triglicerídeos
18.
Rev. osteoporos. metab. miner. (Internet) ; 14(1): 5-12, marzo 2022. tab
Artigo em Espanhol | IBECS | ID: ibc-210534

RESUMO

Esta versión actualizada de la Guía de osteoporosis de la SEIOMM (Sociedad Española de Investigación en Osteoporosis y Metabolismo Mineral) incorpora la información más relevante publicada en los últimos 7 años, desde la Guía de 2015, con estudios de imagen, como la valoración de la fractura vertebral y el análisis del índice trabecular óseo. Además, los avances terapéuticos incluyen los nuevos fármacos anabólicos, los estudios comparativos de la eficacia de los fármacos y la terapia secuencial y combinada. Por ello se actualizan también las recomendaciones de los tratamientos. (AU)


Assuntos
Humanos , Osteoporose , Fraturas Ósseas , Densitometria , Medicina , Alendronato , Ácido Risedrônico , Ácido Zoledrônico , Ácido Ibandrônico , Diagnóstico , Pacientes
19.
Artigo em Espanhol | IBECS | ID: ibc-210535

RESUMO

Esta actualización de las Guías incorpora la información más relevante aparecida durante los 7 años trascurridos desde la publicación de la versión anterior, especialmente en cuanto a procedimientos diagnósticos y opciones terapéuticas. Entre los primeros, merece la pena destacar la incorporación del TBS y la detección de fracturas vertebrales por densitometría. Entre los tratamientos, se consideran los nuevos fármacos anabólicos, los estudios comparativos de eficacia en osteoporosis grave, las pautas de actuación tras la suspensión de los antirresortivos y otros esquemas de tratamiento secuencial y combinado. Teniendo en cuenta todo ello, se actualizan los esquemas de tratamiento recomendados. (AU)


Assuntos
Humanos , Osteoporose , Fraturas Ósseas , Densitometria , Preparações Farmacêuticas , Pacientes , Terapêutica
20.
Molecules ; 27(3)2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35164016

RESUMO

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F254 plates and using acetone-water-chloroform-ethanol-ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first was a 2% aqueous CuSO4×5H2O solution, and the second was a 2',7'-dichlorofluorescein-aluminum chloride-iron (III) chloride system. The applied TLC-densitometric method is selective, linear, accurate, precise, and robust, regardless of the visualizing reagent used for the determination of valproic acid in Convulex capsules. It has low limits of detection (LOD) and limits of quantification (LOQ), which are equal to 5.8 µg/spot and 17.4 µg/spot using a 2% aqueous CuSO4×5H2O solution as visualizing agent and also 0.32 µg/spot and 0.97 µg/spot using a 2',7'-dichlorofluorescein-aluminum chloride-iron (III) chloride system as visualizing reagent, respectively. The described analytical method can additionally be used to study the identity of valproic acid in a pharmaceutical preparation. The linearity range was found to be 20.00-80.00 µg/spot and 1.00-2.00 µg/spot for valproic acid detected on chromatographic plates using a 2% aqueous CuSO4×5H2O solution and the 2',7'-dichlorofluorescein-aluminum chloride-iron (III) chloride system, respectively. A coefficient of variation that was less than 3% confirms the satisfactory accuracy and precision of the proposed method. The results of the assay of valproic acid equal 96.2% and 97.0% in relation to the label claim that valproic acid fulfill pharmacopoeial requirements. The developed TLC-densitometric method can be suitable for the routine analysis of valproic acid in pharmaceutical formulations. The proposed TLC-densitometry may be an alternative method to the modern high-performance liquid chromatography and square wave voltammetry in the control of above-mentioned substances, and it can be applied when other analytical techniques is not affordable in the laboratory.


Assuntos
Densitometria/métodos , Portadores de Fármacos/química , Ácido Valproico/análise , Cápsulas , Cromatografia em Camada Delgada/métodos , Composição de Medicamentos , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Ácido Valproico/administração & dosagem
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