Preparation and in vitro evaluation of melatonin-loaded HA/PVA gel formulations

Melatonin-loaded hyaluronic acid (HA) and poly(vinyl alcohol) (PVA) gels were prepared by using freeze–thaw technique and an emulsion method followed by freeze–thaw technique to produce a new synergistic system for topical application. Freeze–thaw hydrogels and emulgels were characterized by means of Fourier transform infrared spectroscopy, rheology and swelling tests. The porous structure of the hydrogels was shown by scanning electron microscopy observations and thermal properties were tested by differential scanning calorimetry measurements. Bioadhesion and in vitro release characterization of formulations were performed by texture profile analysis and dialysis bag method, respectively. The pore size of both formulations was ranging from 900?nm to 30?μm. Melatonin showed a good compatibility with the polymeric matrices as the pores were smaller for the drug-loaded systems. In vitro release studies showed that the release was improved by emulgel formulations. After 24?h, the release percentage was found to be 13.240%?±?1.094 and 15.192%?±?2.270 for hydrogel and emulgel, respectively. Emulgels had better bioadhesion properties than simple freeze–thaw samples. As a conclusion, regarding the in vitro characterization studies HA and PVA hydrogel and emulgel formulations and their lyophilized forms could be promising systems for topical application of melatonin.     

The use of polyvinyl alcohol hydrogel implants in the lesser metatarsal heads. Is it safely doable? A cadaveric study

BackgroundThe use of synthetic polyvinyl alcohol hydrogel (PVAH) implants for treatment of lesser toe metatarsophalangeal joint (MTPJ) arthritis is promising and currently limited by the size of implants available. The primary objective of this cadaveric study was to investigate the maximum drilling size and largest PVAH implant dimension that could be safely introduced while still preserving an intact bone rim of the lesser metatarsal heads.MethodsHeight and width of all lesser metatarsals were measured on CT and during anatomic dissection. Sequential reaming of the second to fourth metatarsals was performed. Maximum reaming size, largest implant inserted, and failure of the metatarsal head were recorded. Metatarsal head sizes were compared and a multiple regression analysis evaluated measurements that influenced maximum drilling and implant size.ResultsCT and anatomical measurements demonstrated significant correlation (ICC range, 0.–0.85). Mean values for height and width of the metatarsal heads were respectively: second (14.9 mm and 9.9 mm), third (14.8 mm and 8.8 mm), fourth (14.0 mm and 8.7 mm) and fifth (12.3 mm and 9.3 mm). All the second, third and fourth metatarsal heads could be safely drilled up to 7.5 mm, preserving an intact bone rim. At 80% of the time, the heads could be safely drilled up to 8.0 mm. Height of the metatarsal heads was the only factor to significantly influence the size of maximum reaming and implant introduced. In respectively 20%, 40% and 50% of the second, third, and fourth metatarsal heads, neither 8 mm nor 10 mm PVAH implants could be used.ConclusionsOur cadaveric study found that the even though the majority of the lesser metatarsal heads could be safely drilled up to 8 mm, the smallest PVAH implant size currently available in most countries (8 mm) could be inserted in most of the second, but only in about half of the third and fourth metatarsal heads. The remaining bone rim around inserted implants was considerably thin, usually measuring less than 1 mm. In order to optimize the use PVAH in lesser metatarsal heads, smaller implant options are needed.     

可注射水凝胶治疗眼科疾病的研究进展

眼部结构的特殊性使眼科疾病的治疗面临很多阻碍。水凝胶作为一种具备多维应用潜能的高分子材料,有着可控的力学性能及生物性能,是组织工程、生物工程等领域的研究热点。水凝胶良好的透明性、安全性、兼容性也提示了水凝胶在眼科领域广阔的研究前景。目前已应用于眼科的水凝胶有人工泪液、药物载体、黏附剂等。本综述介绍了可注射水凝胶在制作、性能及应用方面的特点,概述了可注射水凝胶作为药物载体、组织黏附剂、空间填充剂以及细胞载体在眼科疾病中的应用进展及挑战,特别介绍了可注射水凝胶近年来在角膜外伤、青光眼、白内障、视网膜脱离及年龄相关性黄斑变性等疾病治疗方面的研究。     

Regenerative potential of basic fibroblast growth factor contained in biodegradable gelatin hydrogel microspheres applied following vocal fold injury: Early effect on tissue repair in a rabbit model

IntroductionPostoperative dysphonia is mostly caused by vocal fold scarring, and careful management of vocal fold surgery has been reported to reduce the risk of scar formation. However, depending on the vocal fold injury, treatment of postoperative dysphonia can be challenging.ObjectiveThe goal of the current study was to develop a novel prophylactic regenerative approach for the treatment of injured vocal folds after surgery, using biodegradable gelatin hydrogel microspheres as a drug delivery system for basic fibroblast growth factor.MethodsVideoendoscopic laryngeal surgery was performed to create vocal fold injury in 14 rabbits. Immediately following this procedure, biodegradable gelatin hydrogel microspheres with basic fibroblast growth factor were injected in the vocal fold. Two weeks after injection, larynges were excised for evaluation of vocal fold histology and mucosal movement.ResultsThe presence of poor vibratory function was confirmed in the injured vocal folds. Histology and digital image analysis demonstrated that the injured vocal folds injected with gelatin hydrogel microspheres with basic fibroblast growth factor showed less scar formation, compared to the injured vocal folds injected with gelatin hydrogel microspheres only, or those without any injection.ConclusionA prophylactic injection of basic fibroblast growth factor -containing biodegradable gelatin hydrogel microspheres demonstrates a regenerative potential for injured vocal folds in a rabbit model.     

Transdermal patches loaded with L-cysteine HCL as a strategy for protection from mobile phone emitting electromagnetic radiation hazards

Mobile phone usage has been increased in the last few years emitting electromagnetic radiation (EMR), which disturbs normal cellular processes via oxidative stress. L-cysteine, a glutathione precursor, prevents oxidative damage. Transdermal patches (TDPs) loaded with L-cysteine hydrochloride (L-CyS-HCL) were fabricated by dispersion of L-CyS-HCL 5% w/w and different concentrations of sorbitol as a plasticizer in room-temperature vulcanizable synthetic silicone matrices (RTV-Si). The effect of sorbitol on patch physicochemical parameters was assessed; in-vitro L-CyS-HCL release profiles and ex-vivo permeation were studied. Pharmacokinetic parameters of endogenous synthetized in-vivo glutathione, after receiving IV bolus dose of L-CyS-HCl and L-CyS-HCl-RTV-Si-TDPs were studied in rat model. The influence of L-CyS-HCL-RTV-Si-TDPs against damaging effects of mobile phone EMR on rats' blood and brain tissues was studied. The results revealed that patch plasticity, intensity reflections, surface porosity, L-CyS-HCL release rate and skin permeation increased with increasing sorbitol concentration. Pharmacokinetic profile for IV dose and L-CyS-HCl-RTV-Si-TDPs revealed that the L-CyS-HCl-RTV-Si-TDPs provided a sustained glutathione plasma concentration–time profile over entire patch application. High significant differences in biological parameters (blood and brain samples) were observed for radiated rats using the patch in study compared with positive control rats. Promising long-term strategy for protection against mobile phone hazards was obtained.     

软骨组织工程用羧甲基壳聚糖/氧化海藻酸钠 复合水凝胶的制备及体外评估

目的 优化羧甲基壳聚糖/氧化海藻酸钠（CMCS/OSA）复合水凝胶制备工艺,并应用于软骨组织工程。方法 制备氨基与醛基比例分别为2:1、1:1、1:2的CMCS/OSA复合水凝胶,并通过扫描电子显微镜观察、流变学检测、黏附拉力测试、溶胀率分析及细胞实验等方法评价复合水凝胶的微观形态、物理特性以及生物相容性,以制备满足软骨再生领域需求的水凝胶。结果 氨基与醛基比为1:1时,制备出的水凝胶具有良好的孔隙率、适宜的成胶时间、较强的黏附力及稳定的溶胀率等性质,对细胞有良好的生物相容性。结论 氨基与醛基比为1:1时制备出的CMCS/OSA复合水凝胶是软骨组织工程优异的支架材料。