Rheology and in vitro release properties of thermosensitive in situ gel of Yihuang Decoction and its common gel for vaginal use / 中国中药杂志

To evaluate the traits and rheological properties of thermosensitive in situ gel of Yihuang Decoction and its common gel for vaginal use, and predict the release behavior of Yihuang Decoction in situ gel in vitro. Poloxamer was used as thermosensitive material to prepare Yihuang Decoction vaginal in situ gel, and Yihuang Decoction common gel was prepared with carbopol. Then the differences of the two gels before and after diluting with vaginal fluid were compared. The rheological parameters of Yihuang Decoction in situ gel and its common gel were determined with Anton Paar MCR102 rheometer. In addition, berberine hydrochloride was selected as an index component to evaluate the in vitro release properties of Yihuang Decoction vaginal thermosensitive in situ gel. Yihuang Decoction vaginal thermosensitive in situ gel was Newtonian fluid under low-temperature conditions, which was yellow and transparent. After reaching the gelling temperature of 24.5 ℃, it became semi-solid, pseudoplastic fluid. The gelling temperature was predicted to be 37 ℃, and the phase transition time was 30 s after diluting with simulated vaginal fluid. However, the rheological properties of Yihuang Decoction common gel had no significant changes with temperature. Compared with in situ gel, the color of common gel was darker and more translucent. Besides, its mobility was stronger after diluting with simulated vaginal fluid. The in vitro release study showed that the kinetic behavior of berberine hydrochloride in Yihuang Decoction vaginal thermosensitive in situ gel was matched with the Higuchi equation. Through simulation of vaginal administration, physical properties and dynamic rheological parameters were used to intuitively and scientifically evaluate the two gels. Compared with the common gel, the thermosensitive in situ gel could quickly attached to the vaginal mucosa and release drug, and thus was more suitable for developing vaginal administration of Yihuang Decoction, which also provides references for studying new vaginal preparation of Yihuang Decoction.

Three-dimensional structure and cytokine distribution of platelet-rich fibrin

OBJECTIVES: Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1) can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. METHODS: Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg); it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. RESULTS: Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5) to low at the plasma end (p=0.19). Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. CONCLUSION: Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians.

Comparison of Antimicrobial Effect of Alcohol Gel according to the Amount and Drying Time in Health Personnel Hand Hygiene

PURPOSE: The purpose of this study was to compare the effect of alcohol gel according to the amount and drying time in health personnel hand hygiene and to promote in their practice adequate and effective hand hygiene. METHODS: The cross-over experimental study was performed with 14 volunteers. Hands were artificially contaminated with 5 mL of 10(8) CFU/mL of Serratia marcescens (ATCC 14756) and four different alcohol gel hand hygiene methods varying by the amount of alcohol gel (2 mL vs. 1 mL) and drying time (complete vs. incomplete) were compared. Samples were collected by glove juice sampling procedures. RESULTS: Mean log reduction values of the four different hand hygiene methods were 2.22+/-0.36, 1.26+/-0.53, 1.49+/-0.60, 0.89+/-0.47 respectively for the 4 groups: adequate amount (2mL) and complete dry (30 seconds rubbing followed by 2 min air-dry), inadequate amount (1 mL) and complete dry, adequate amount and incomplete dry (15 seconds rubbing and no air-dry), and inadequate amount and incomplete dry. The difference was statistically significant in the adequate amount and complete dry group compared to other three groups (p<.001). CONCLUSION: Only alcohol gel hand hygiene with adequate amount and complete drying was satisfactory by U.S. FDA-TFM efficacy requirements for antiseptic hand hygiene products.

Formulation and in vitro evaluation of clotrimazole gel containing almond oil and tween 80 as penetration enhancer for topical application

Achieving a desirable percutaneous absorption of drug molecule is a major concern in formulating dermal and transdermal products. The use of penetration enhancers could provide a successful mean for this purpose. The aim of this study was to develop Clotrimazole gel and to evaluate the effect of almond oil and tween 80 [in different concentrations], on the permeation of drug through rabbit skin in vitro. In order to investigate the effect of penetration enhancers used in this study on the permeation of Clotrimazole through sections of excised rabbit skin, Franz diffusion cell was employed. Sample solution was withdrawn at specific time interval up to 24 h. Significant difference in permeation among the eight formulations was seen in the study. The permeation profile of various formulations also showed that the added enhancers in individual batches affected the permeation of the drug. Drug permeation increased with increased concentration of Tween 80 and decreased concentration of almond oil. Furthermore, almond oil combined with tween 80 showed synergistic effect. The clotrimazole gels were successfully formulated and could be beneficial for topical use

[Comparison of fluoride uptake into enamel from sodium fluoride gel 0.05% produced in Iran and stannous fluoride 0.4% gel]

The present study compared fluoride uptake into enamel from sodium fluoride 0.05% gel and American Dental Association approved fluoride gel [Stannous fluoride 0.4%, Sultan Co.] when used on healthy enamel of the intact teeth. In an experimental study, 30 intact teeth extracted for orthodontic purposes were randomly assigned into two groups of 15 teeth. The teeth were sectioned in two mesial and distal halves as control and experimental sides. Defined semi-circular areas on the enamel of experimental halves were treated with gel for 4 minutes, the halves were stored in artificial saliva for 24 hours at 37§C, etched for 30 seconds by 0.5 M perchlorid Acid and washed by 0.2 ml KOH after each etching. Biopsy of the samples was obtained by Acid Etch Enamel Biopsy technique and the fluoride and calcium concentration were calculated by potentiometer and spectrophotometer respectively. Paired t test and student t test were used for statistical analyses. The results showed significant increase of enamel fluoride content in the experimental halves after exposure to both stannous fluoride 0.4% [P=0.0001] and sodium fluoride 0.05% [P=0.009]. Mean fluoride uptakes in stannous fluoride 0.4% gel and sodium fluoride 0.05% gel groups were respectively 4052.5 ppm and 892.5 ppm that shows statistically significant difference [P=0.0001]. Although both sodium fluoride 0.05% and stannous fluoride 0.4% increased fluoride Content of tooth enamel after application, stannous fluoride 0.4% caused more fluoride uptake into the tooth enamel that is due to its higher amount of fluoride ion [1000 ppm] compared to sodium fluoride gel [225 ppm]

Ultrastructural evaluation of human keratinocyte growth and differentiation on a fibrin substrate / Avaliação ultraestrutural do crescimento e da diferenciação de queratinócitos sobre um substrato de fibrina

PURPOSE: In order to circumvent several difficulties that have been met in the routine use of the in vitro keratinocyte cultures using the standard procedure described by Rheinwald and Green, and obtain a more resilient and the least possible immunogeneic skin substitute for a future clinical application, this work studied a new keratinocyte culture system, which envisages the utilization of a fibrin substrate in association with high densities of human keratinocytes. METHODS: Through light and transmission electron microscopy and immunohistochemical assays, long-term proliferative and differentiative characteristics of keratinocytes cultured onto a fibrin gel under immerse and air-liquid interface culture conditions were evaluated. RESULTS: Despite the absence of a dermal substitute, the results demonstrated that the proposed composite was constituted of a transparent and elastic fibrin film covered by a well-attached, multistratified epithelium with morphological characteristics that resemble human epidermis, including the neoformation, albeit incomplete, of the basement membrane. CONCLUSIONS: Increased mechanical resistance due to the presence of an easy handling substrate, the delivery of nonclonfluent keratinocytes as well as the removal of animal-derived cells from the culture system suggest its potential use for future transplantation purposes.

OBJETIVO: Com o intuito de contornar diversas dificuldades encontradas no uso rotineiro de queratinócitos cultivados in vitro pela técnica descrita por Rheinwald e Green, e obter um substituto cutâneo mais resistente e o menos imunogênico possível para futuras aplicações clínicas, este trabalho avaliou um novo sistema de cultura de queratinócitos que prevê a utilização de um substrato de fibrina em associação com queratinócitos humanos em alta densidade. MÉTODOS: Através de microscopia óptica e eletrônica e análise imunohistoquímica, foram avaliadas as características proliferativas e de diferenciação em longo prazo de queratinócitos cultivados em condição imersa e na interface ar-líquido. RESULTADOS: Apesar da ausência de um substituto dérmico, foi demonstrado que o composto proposto constituiu-se de um substrato de fibrina transparente e elástico coberto por epitélio multi-estratificado, bem aderido, com características morfológicas semelhantes à epiderme humana, incluindo a neo-formação, embora incompleta, da membrana basal. CONCLUSÕES: A maior resistência mecânica com a presença de um substrato de fácil manuseio, a possível liberação de queratinócitos não-confluentes, e a remoção de células com origem animal dos sistemas de cultura sugerem que o composto proposto neste estudo apresenta grande potencial para uso clínico futuro.

Studies on development of controlled delivery of combination drug(s) to periodontal pocket.

Aim: The aim of this study to develop the controlled delivery of combination drug(s) to periodontal pocket. Materials and Methods: In the present investigation mucoadhesive gel formulations were prepared using carboxy methylcellulose (CMC), methylcellulose (MC), hydroxyethylcellulose (HEC), polyvinylpirrolidone (PVP), polycarbophil (PC), and poloxamer. Each formulation was characterized in terms of polarizing light microscopy, gelation, gel melting, hardness, compressibility, adhesiveness, cohesiveness, syringeability, adhesion to a mucin disk, rheological studies, drug release, and antibacterial activities. Addition of CMC and PVP to the gel favored hexagonal phase formation. The gelation temperature was decreased linearly with an increasing concentration of drug(s), whereas, the melting temperature increased with the concentration of drug(s). Increasing the concentrations of each polymeric component significantly increased formulation hardness, compressibility, adhesiveness, mucoadhesion, and syringeability, yet a decreased cohesiveness. Increased time of contact between the formulation and mucin significantly increased the required force of detachment. Drug release from all formulations was non-diffusion controlled and significantly decreased as the concentration of the polymer was increased, due to the concomitant increased viscosity of the formulations and the swelling kinetics of PC, following contact with the dissolution fluid. Result: Antibacterial studies revealed that a gel with 30% HEC had a growth inhibition zone on agar with all three strains. Conclusion: Formulations containing HEC exhibited superior physical characteristics for improved drug delivery to the periodontal pocket and are now the subject of long-term clinical investigations.

Avaliaçäo in vitro da superfície de resinas compostas e de ionômeros de vidro submetidas a tratamento com géis fluoretados / In vitro evaluation of the effects of fluoride gels on composite resins and on glass ionomer cements

O objetivo do trabalho é verificar o efeito da aplicaçäo de um gel de fluorfosfato acidulado (pH=3,5) e de um gel de fluoreto de sódio (pH neutro) sobre resinas compostas de quatro fabricantes (Adaptic, Heliomolar, Herculite e Z100) e dois ionômeros de vidro, um convencional (Vidrion) e outro resino-reforçado (Vitremer). A rugosidade da superfície dos corpos-de -prova foi avaliada antes e após a aplicaçäo dos géis por 4 min, 16 min ou 24 h, utilizando um rugosímetro Surftest 211-Mitutoyo. A análise estatística indicou um aumento significativo na rugosidade de todos os materiais tratados com flúor neutro em relaçäo ao controle (tratado com água), com maior intensidade para o tratamento por 24 horas. Em todos os grupos houve um acréscimo adicional significativo (p<0,01) de rugosidade (em relaçäo aos grupos tratados com gel neutro) quando o tratamento foi feito com gel acidulado com pH=3,5