An Innovative Method Development And Forced Degradation Studies For Simultaneous Estimation Of Sofosbuvir And Ledipasvir By Rp Hplc

Objective: To develop an innovative, rapid, simple, cost-effective, stability indicating reverse phase-high performance liquid chromatography (RP-HPLC) method for simultaneous estimation of ledipasvir (LP) and sofosbuvir (SB) in combination pill dosage form. Methods: The method was developed using C8 column, 250 mm x 4.6 mm, 5 mm using mobile section comprising of 0.1% (v/v) orthophosphoric acid buffer at pH 2.2 and acetonitrile in the ratio of 45:55 that was pumped through the column at a flow rate of 0.8 ml/min. Temperature was maintained at 30 °C, the effluents were monitored at 260 nm with the help of usage of PDA detector. Results: The retention time of LP and SB were found to be 2.246 min and 3.502 min. The approach was found to be linear with the variety of 9-36 µg/ml and 40-240 μg/ml for LP and SB respectively, the assay of estimated compounds were found to be 99.65% and 99.73% w/v for LP and SB respectively. Conclusion: The pressured samples changed into analyzed and this proposed a technique turned into determined to be particular and stability indicating as no interfering peaks of decay compound and excipients were observed. Hence, the approach was easy and economical that may be efficiently applied for simultaneous estimation of both LP and SB in bulk and combination tablet system.

Comparação da degradação da força de elásticos ortodônticos intermaxilares de látex e sintéticos quando submetidos à distensão em saliva artificial / Comparison of force degradation intermaxilary latex and synthetic orthodontic elastics distended in artificial saliva

Introdução: os elásticos intermaxilares sintéticos surgiram como uma alternativa para uso ortodôntico em pacientes com sensibilidade ao látex, porém, diferenças podem ser observadas quando comparados aos elásticos naturais de látex. Objetivo: comparar a quantidade de degradação de força dos elásticos intermaxilares sintéticos e de látex quando distendidos em saliva artificial, a fim de buscar parâmetros clínicos para o uso de um protocolo sobre a frequência de troca desses elásticos nas terapias ortodônticas em pacientes com sensibilidade ao látex ou não. Metodologia: foram utilizados dois grupos contendo 30 elásticos cada. O grupo 1 com 30 elásticos de látex da marca Morelli de força média e diâmetro de 5/16" e o grupo 2, 30 elásticos sintéticos, sem látex, também da marca Morelli de força média e diâmetro de 5/16". Eles foram distendidos 4cm e submersos em saliva artificial a 37 graus Celsius e tiveram força mensurada com dinamômetro ortodôntico ao início e nos intervalos de 24, 48, 72 e 120 horas após a imersão. A avaliação da degradação da força foi realizada calculando o percentual de força perdida em relação à força inicial em cada intervalo de tempo, para cada grupo testado separadamente e também entre eles. Resultados e Discussão: a média de valores dos elásticos tanto de silicone quanto de látex teve um percentual parecido quanto à degradação de forças, visto que após as primeiras 24 horas ocorreu o maior declínio de força, de aproximadamente 11% ambos os elásticos. Após 48 horas esse percentual não se alterou significativamente. Conclusão: elásticos devem ser trocados em até 48 horas para que a força aplicada se mantenha em índices aceitáveis.

Introduction: synthetic intermaxillary elastics have emerged as an alternative for orthodontic use in patients with latex sensitivity, but differences can be observed when compared to natural latex elastics. Objective: compare the amount of force degradation of synthetic intermaxillary elastics and latex when distended in artificial saliva in order to find clinical parameters for the use of a protocol on the frequency of exchange of these elastics in orthodontic therapies in patients with latex sensitivity or not. Method: for this, two groups containing 30 elastics were used. Group 1 with 30 medium strength and diameter 5/16 "Morelli latex elastics and group 2, 30 synthetic latex-free elastics, also of the medium strength and 5/16" diameter Morelli brand. They were stretched 4cm and submerged in artificial saliva at 37 degrees Celsius and had strength measured with orthodontic dynamometer at the beginning and at the intervals of 24, 48, 72 and 120 hours after immersion. The force degradation assessment was performed by calculating the percentage of force lost in relation to the initial force at each time interval, for each group tested separately and also between them. Results and discussion: the mean elastic values of both silicone and latex had a similar percentage for the degradation of forces, since after the first 24 hours the greatest force decline occurred, of approximately 11% both elastics. After 48 hours this percentage did not change significantly. Conclusion: elastics should be changed within 48 hours so that the force applied remains at acceptable rates.

Discoloration and force degradation of orthodontic elastomeric ligatures

ABSTRACT OBJECTIVE: The aim of the present study was to evaluate color changes and force degradation of orthodontic elastomeric ligatures in different stretching patterns during a 8-weeks period. METHODS: Two elastomers with the minimum and two with the maximum color changing, and gray elastomers of two brands (American Orthodontics and Ortho Technology) were selected according to an opinion poll with clinicians and color changes after 4 weeks of intraoral use were evaluated. These elastomers were mounted on special jigs fabricated using a CAD-CAM technique, underwent different stretching patterns and the force was measured in 0, 24 hours, 2, 4 and 8 weeks. During in vivo part of the study, force levels of elastomers were measured after 4 weeks on a material testing machine. Data were analyzed with four-way ANOVA and Tukey post hoc tests. RESULTS: All the elastomers showed color changing but the degree of color stability was significantly different. The mean force degradation was higher in 1-mm stretch groups. After 8 weeks, the average residual force of elastomers was 1.45 ± 0.18 N and the maximum force decay was seen in the elastomers that exhibited the maximum initial force. CONCLUSION: There is significant relationship between the stretching pattern and the amount of residual force of elastomers. Elastomers with higher initial forces exhibited higher percentages of force loss after 8 weeks. It seems that there is a relationship between initial color and color changing of elastomers.

RESUMO OBJETIVO: o objetivo do presente estudo foi avaliar as alterações de cor e a degradação da força de ligaduras elásticas em diferentes padrões de estiramento, durante um período de 8 semanas. MÉTODOS: duas ligaduras elásticas com alteração mínima de cor, duas com alteração máxima de cor e ligaduras elásticas na cor cinza de duas marcas comerciais (American Orthodontics e Ortho Technology) foram selecionadas de acordo com uma pesquisa de opinião com clínicos, e mediante a avaliação das alterações de cor após quatro semanas em uso intrabucal. Essas ligaduras elásticas foram montadas em jigs fabricados por meio da técnica CAD-CAM e foram expostas a diferentes padrões de estiramento, e a força foi medida nos tempos de 0h, 24h; 2, 4 e 8 semanas. Durante a parte in vivo do estudo, os níveis de força das ligaduras elásticas foram medidos após 4 semanas, em uma máquina de teste de materiais. Os dados foram analisados com os testes ANOVA de quatro vias e post-hoc de Turkey. RESULTADOS: todas as ligaduras elásticas mostraram alterações de cor, mas houve diferenças significativas quanto ao grau de estabilidade da cor. A média de degradação da força foi mais alta nos grupos com estiramento a 1 mm. Após 8 semanas, a média da força residual nas ligaduras elásticas foi de 1,45 ± 0,18 N e a maior degradação na força foi observada nas ligaduras elásticas que apresentaram a maior força inicial. CONCLUSÃO: há uma relação significativa entre o padrão de estiramento e a quantidade de força residual nas ligaduras elásticas. As ligaduras elásticas com as maiores forças iniciais exibiram as mais altas porcentagens de degradação da força após 8 semanas. É, também, possível que haja uma relação entre a cor inicial da ligadura elástica e sua alteração de cor.

Evaluation of Change - In - Schedule of Intra Oral Orthodontic Elastic In A Simulated Oral Environment - An In - Vitro Study.

This project evaluated the change- in -schedule of intra oral orthodontic elastics in a simulated oral environment. The bands of two manufacturers’ American orthodontics and Dentarum were examined with three bands in each subgroup of two groups (I and II). The initial force delivered by randomly selected intra oral elastics was recorded for extensions of 225%, 300% and 450%. Then the elastics were engaged on to a special jig having posts at a distance of 14.8mm, 19mm and 28.4mm in order to extend the diameter of elastics by 225%, 300% and 450% respectively and incubated at 37˚C in artificial saliva for 24 and 48 hours of time. Force degradation of intra oral elastics was calculated in grams. Data was analyzed using ANOVA. The force degradation was high during first 24 hours and the elastics should be changed on a daily basis.

Elastic force degradation of synthetic elastomeric chain / 대한치과교정학회지

The purpose of this study was to evaluate the force degradation rate of synthetic elastomeric chains during space closing phase of orthodontic treatment. Two kinds of synthetic elastomeric chains(RMO, 3M) were selected which were commonly used in clinics. All of the samples were extended and tested for 4 weeks under the simulated intraoral condition. The results can be summarized as follows : 1. Time related residual force showed typical logarithm function. Residual force after 4 weeks was 41.2~64.6 % of original force, and difference between two kinds of elastomeric chain existed. 2. Elastic force decreased greatly during first 10 minutes, so 20~25 % of original force disappeared. After that, this decreasing tendency was diminished significantly, average rate of elastic force after 1 week to 4 weeks were 1.5 % demonstrating rather constant force. 3. Even though the same brand of elastomeric chiain was used, as extension rate of elastomeric chain increased, force degradation rate increased by decreasing of residual force.