原料药粒径对头孢地尼颗粒体外溶出行为的影响

目的：考察原料药粒径对头孢地尼颗粒体外溶出度的影响。方法参照2010版中国药典第二法,以 pH ＝6．8磷酸盐缓冲液为溶出介质,转速为50 r·min －1,采用紫外分光光度法为分析方法,考察不同粒径的原料制备的头孢地尼颗粒与参比制剂溶出的一致性。结果粒径为 D90：142．90μm、D50：30．25μm、D10：3．47μm（100目筛）和 D90：51．21μm、D50：10．71μm、D10：2．25μm（200目筛）的头孢地尼原料制成的颗粒溶出行为与原研不相似;在不同溶出介质中,D90：35．62μm、D50：6．98μm、D10：1．66μm 的头孢地尼原料制成的颗粒,与参比制剂的溶出行为均相似。结论建立的分析方法简单可靠,原料微粉化能够有效提高难溶性药物的溶出度。     

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging.     

Can possible toxic effect of ultraviolet-A after corneal cross-linking be prevented? In vitro transmittance study of contact lenses at 370 nm wavelength

Context: Corneal collagen cross linking (CCL) with ultraviolet A (UVA) has been proposed as a treatment for the progression of corneal ectasia associated with keratoconus and post-laser-assisted in situ keratomileusis (LASIK) ectasia. Despite the reports about safety of procedure, we consider that UVA of sunlight can effect riboflavin saturated and de-epitelizated cornea early after CCL.

Objectives: To evaluate the UVA blockage capability of 11 different silicone hydrogel contact lenses which are widely used after CCL treatment.

Methods: Eleven different silicone hydrogel and daily disposable contact lenses were evaluated. The UVA light at 365?nm wavelength for UVA source and UV light meter to measure UVA radiation were used. 3, 9 and 18?mW/cm² power of UV radiance was applied centrally to the each type of contact lenses. The power of UVA transmittance for each radiance and percentage of blockage were evaluated for each brand. Also, protection factor (PF) was calculated.

Results: The senofilcon A and narafilcon A had the highest blockage and lowest transmittance (p?=?0.02). PF was significantly higher in the senofilcon A and narafilcon A at 3, 9 and 18?mW/cm² (p?=?0.0001). And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B had the highest UVA transmittance.

Conclusion: The narafilcon A and the senofilcon A may be a good options for epithelial healing after CCL procedure to protect the cornea from UVA of sunlight. And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B contact lenses that have high-UVA transmittance feature can be a treatment choice for contact lens-assisted CCL technique in thin corneas.     

Deleting the BAFF receptor TACI protects against systemic lupus erythematosus without extensive reduction of B cell numbers

B cell-activating factor of the TNF family (BAFF) is an essential B cell survival factor. However, high levels of BAFF promote systemic lupus erythematosus (SLE) in mice and humans. Belimumab (anti-human BAFF) limits B cell survival and is approved for use in patients with SLE. Surprisingly, the efficacy of rituximab (anti-human CD20) in SLE remains controversial, despite depleting B cells more potently than belimumab. This raises the question of whether B cell depletion is really the mechanism of action of belimumab. In BAFF transgenic mice, SLE development is T cell-independent but relies on innate activation of B cells via TLRs, and TLR expression is modulated by the BAFF receptor TACI. Here, we show that loss of TACI on B cells protected against BAFF-mediated autoimmune manifestations while preserving B cells, suggesting that loss of BAFF signaling through TACI rather than loss of B cells may underpin the effect of belimumab in the clinic. Therefore, B cell-sparing blockade of TACI may offer a more specific and safer therapeutic alternative to broad B cell depletion in SLE.     

降钙素基因相关肽对血管平滑肌细胞心肌素表达及细胞表型改变的作用

目的:研究降钙素基因相关肽(CGRP)对血管平滑肌细胞(VSMCs)心肌素表达的影响及对细胞表型改变的调节作用。方法:取大鼠胸主动脉,以组织块贴壁培养法获得VSMCs,分为对照组、血管紧张素Ⅱ(AngⅡ)组(加入AngⅡ处理)、CGRP组(加入AngⅡ和CGRP处理)和CGRP8-37组(在AngⅡ和CGRP基础上加入CGRP8-37)。Western blot法检测VSMCs中心肌素及细胞表型标志蛋白α-平滑肌肌动蛋白(α-SMA)和骨桥蛋白(OPN)表达情况。结果:在VSMCs培养中,细胞心肌素表达水平随着培养时间延长逐渐降低,细胞培养48 h和72h时心肌素表达水平较基线水平显著降低(P0.05);而加入CGRP处理后,心肌素表达水平逐渐增加,与基线水平比较,加入CGRP培养后48 h和72 h时细胞心肌素水平显著增加(P0.05)。同时,在VSMCs培养48 h时,AngⅡ组细胞心肌素水平较对照组下降(P0.05),且α-SMA表达亦相应下降(P0.05),而OPN表达水平显著增加(P0.05);CGRP组VSMCs心肌素水平较AngⅡ组增加,伴随着α-SMA表达水平增加(P0.05),相反地OPN表达水平下降(P0.05);CGRP8-37组心肌素和α-SMA表达水平较CGRP+AngⅡ组降低(P0.05),而OPN表达较CGRP组增加(P0.05)。结论:CGRP通过促进VSMCs心肌素的表达而抑制细胞表型转换,使细胞维持收缩表型,且这一作用是CGRP通过与其受体结合后实现的。     

Advances in understanding the molecular basis of the first steps in color vision

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis–trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation.     

Climatic droplet keratopathy: an old disease in new clothes

Climatic droplet keratopathy (CDK) is an acquired and potentially handicapping cornea degenerative disease that is highly prevalent in certain rural communities around the world. It predominantly affects males over their forties. It has many other names such as Bietti's band‐shaped nodular dystrophy, Labrador keratopathy, spheroidal degeneration, chronic actinic keratopathy, oil droplet degeneration, elastoid degeneration and keratinoid corneal degeneration. CDK is characterized by the haziness and opalescence of the cornea's most anterior layers which go through three stages with increasing severity. Globular deposits of different sizes may be histopathologically observed under the corneal epithelium by means of light and electron microscopy. The coalescence and increased volume of these spherules may cause the disruption of Bowman's membrane and the elevation and thinning of the corneal epithelium. The exact aetiology and pathogenesis of CDK are unknown, but they are possibly multifactorial. The only treatment in CDK advanced cases is a corneal transplantation, which in different impoverished regions of the world is not an available option. Many years ago, the clinical and histological aspects of this disease were described in several articles. This review highlights new scientific evidence of the expanding knowledge on CDK's pathogenesis which will open the prospect for new therapeutic interventions.     

Contribution of rivaroxaban to the international normalized ratio when switching to warfarin for anticoagulation as determined by simulation studies

Aim

This study evaluated the influence of rivaroxaban 20 mg once daily on international normalized ratio (INR) during the co-administration period when switching from rivaroxaban to warfarin.

Methods

We developed a calibrated coagulation model that was qualified with phase I clinical data. Prothrombin time and INR values were simulated by use of phospholipid concentrations that matched Neoplastin Plus® and Innovin® reagents. To simulate the combined effects of rivaroxaban and warfarin on INR during switching, warfarin initiation was simulated by adjusting the magnitude of the warfarin effect to reach the desired target INRs over the course of 21 days. The warfarin effect values (obtained every 6 h) and the desired rivaroxaban plasma concentrations were used. Nomograms were generated from rivaroxaban induced increases in INR.

Results

The simulation had good prediction quality. Rivaroxaban induced increases in the total INR from the warfarin attributed INR were seen, which increased with rivaroxaban plasma concentration. When the warfarin only INR was 2.0–3.0, the INR contribution of rivaroxaban with Neoplastin Plus® was 0.5–1.2, decreasing to 0.3–0.6 with Innovin® at median trough rivaroxaban plasma concentrations (38 μg l⁻¹).

Conclusions

The data indicate that measuring warfarin induced changes in INR are best performed at trough rivaroxaban concentrations (24 h after rivaroxaban dosing) during the co-administration period when switching from rivaroxaban to warfarin. Furthermore, Innovin® is preferable to Neoplastin Plus® because of its substantially lower sensitivity to rivaroxaban, thereby reducing the influence of rivaroxaban on the measured INR.     

Calendering as a direct shaping tool for the continuous production of fixed-dose combination products via co-extrusion

In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed-dose combination products in a continuous way. Co-extrudates with a metoprolol tartrate-loaded sustained-release core and a hydrochlorothiazide-loaded immediate-release coat were produced and immediately shaped into a monolithic drug delivery system via calendering, using chilled rolls with tablet-shaped cavities. In vitro metoprolol tartrate release from the ethylcellulose core of the calendered tablets was prolonged in comparison with the sustained release of a multiparticulate dosage form, prepared manually by cutting co-extrudates into mini-matrices. Analysis of the dosage forms using X-ray micro-computed tomography only detected small differences between the pore structure of the core of the calendered tablet and the mini-matrices. Diffusion path length was shown to be the main mechanism behind the release kinetics. Terahertz pulsed imaging visualized that adhesion between the core and coat of the calendered tablet was not complete and a gradient in coat thickness (varying from 200 to 600 μm) was observed. Modulated differential scanning calorimetry and X-ray diffraction indicated that the solid-state properties of both drugs were not affected by the calendering procedure.