Delivery and Biodistribution of Traceable Polymeric Micellar Diclofenac in the Rat

The nonsteroidal anti-inflammatory drugs elevate cardiovascular risk, perhaps, due to their accumulation in the heart and kidneys. We designed nanodelivery systems for cardiotoxic diclofenac to reduce its presence in these organs. Diclofenac ethyl ester (DFEE) was encapsulated in traceable micelles based on poly(ethylene oxide)-b-poly(ε-caprolactone) (DFEE-PCL-TM) or poly(ethylene oxide)-b-poly(α-benzyl carboxylate-ε-caprolactone) (DFEE-PBCL-TM). Diclofenac pharmacokinetics and tissue distribution were studied after intravenous (iv) and intraperitoneal administration of the nanoformulations and compared with those after iv doses of free diclofenac (n = 3-6/group). The average diameters for DFEE-PBCL-TM and DFEE-PCL-TM were 37.2 ± 0.06 and 45.1 ± 0.06 nm, respectively. Drug concentration dropped below the assay sensitivity after free drug administration in 6 h, but persisted for 24 h following DFEE-PBCL-TM (2.3 ± 1.4 μg/mL) and DFEE-PCL-TM (1.9 ± 0.6 μg/mL) iv administration. The diclofenac heart:blood and kidney:blood ratios were 5- to 12-fold lower with the nanoformulations than with free diclofenac. Near-infrared fluorescence measurements in tissues suggested exposure patterns to nanocarriers parallel with those achieved for delivered diclofenac by nanoformulations. Administration of DFEE-PCL-TM by iv or intraperitoneal injection, resulted in comparable pharmacokinetics and 6 h postdose near-infrared fluorescence in the heart, kidneys, liver, and spleen. When compared to each other, DFEE-PBCL-TM showed significantly lower diclofenac levels in the heart compared to DFEE-PCL-TM (0.3 ± 0.03 vs. 0.5 ± 0.1 μg/g). Developed nanoformulations of diclofenac prolonged diclofenac circulation and reduced its presence in the heart and kidneys, strongly suggesting cardiac-safe delivery vehicles for diclofenac.     

Particle Size Distribution Analysis of OTC Aerosol or Powder Drug Products With Potential for Inadvertent Inhalation Exposure to Consumers

The potential for inadvertent inhalation of over-the-counter (OTC) aerosol/powder drug products for topical application requires understanding of the characteristic size distributions of the airborne particles or droplets generated when these products are used as per the directions on the product label. Particle/droplet size is an important factor in determining the depth of particle penetration into the respiratory system after inhalation. Because particles penetrating beyond the larynx into the lung may lead to adverse respiratory effects, OTC aerosol or powder drug product particle size distribution is important to characterize. In this study, laser diffraction was used to analyze the particle size distribution of 32 currently marketed OTC drug products as emitted after actuation or air dispersion from their final package. Among the products surveyed were sunscreens, antiperspirants, topical analgesics, skin protectants, and acne products. The results may be useful to the U.S. Food and Drug Administration in its mission to protect as well as promote public health.     

A Nonionic Polyethylene Oxide (PEO) Surfactant Model: Experimental and Molecular Dynamics Studies of Kolliphor EL

Polyethoxylated, nonionic surfactants are important constituents of many drug formulations, including lipid-based formulations. In an effort to better understand the behavior of formulation excipients at the molecular level, we have developed molecular dynamics (MD) models for the widely used surfactant Kolliphor EL (KOL), a triricinoleate ester of ethoxylated glycerol. In this work, we have developed models based on a single, representative molecular component modeled with 2 force field variations based on the GROMOS 53A6_DBW and 2016H66 force field parameters for polyethoxylate chains. To compare the computational models to experimental measurements, we investigated the phase behavior of KOL using nephelometry, dynamic light scattering, cross-polarized microscopy, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The potential for digestion of KOL was also evaluated using an in vitro digestion experiment. We found that the size and spherical morphology of the KOL colloids at low concentrations was reproduced by the MD models as well as the growing interactions between the aggregates to from rod-like structures at high concentrations. We believe that this model reproduces the phase behavior of KOL relevant to drug absorption and that it can be used in whole formulation simulations to accelerate the formulation development.     

Effect of biomimetic mineralization on enamel and dentin: A Raman and EDX analysis

ObjectiveTo investigate the effect of an experimental biomimetic mineralization kit (BIMIN) on the chemical composition and crystallinity of caries-free enamel and dentin samples in vitro.MethodsEnamel and dentin samples from 20 human teeth (10 for enamel; 10 for dentin) were divided into a control group without treatment and test samples with BIMIN treatment. Quantitative analysis of tissue penetration of fluoride, phosphate, and calcium was performed using energy-dispersive X-ray spectroscopy (EDX). Mineralization depth was measured by Raman spectroscopy probing the symmetric valence vibration near 960 cm⁻¹ as a marker for crystallinity. EDX data was statistically analyzed using a paired t-test and Raman data was analyzed using the Student’s t-test.ResultsEDX analysis demonstrated a penetration depth of fluoride of 4.10 ± 3.32 μm in enamel and 4.31 ± 2.67 μm in dentin. Calcium infiltrated into enamel 2.65 ± 0.64 μm and into dentin 5.58 ± 1.63 μm, while the penetration depths for phosphate were 4.83 ± 2.81 μm for enamel and 6.75 ± 3.25 μm for dentin. Further, up to 25 μm of a newly mineralized enamel-like layer was observed on the surface of the samples. Raman concentration curves demonstrated an increased degree of mineralization up to 5–10 μm into the dentin and enamel samples.SignificanceBiomimetic mineralization of enamel and dentin samples resulted in an increase of mineralization and a penetration of fluoride into enamel and dentin.     

An in vitro study of a novel quaternary ammonium silane endodontic irrigant

ObjectiveTo analyze effect of NaOCl + 2% quaternary ammonium silane (QAS)-containing novel irrigant against bacteria impregnated inside the root canal system, and to evaluate its antimicrobial and mechanical potential of dentine substrate.MethodsRoot canal was prepared using stainless steel K-files™ and ProTaper™ and subjected to manual and ultrasonic irrigation using 6% NaOCl + 2% CHX, 6% NaOCl + 2% QAS and saline as control. For confocal-microscopy, Raman spectroscopy and SEM analysis before and after treatment, Enterococcus faecalis cultured for 7 days. Raman spectroscopy analysis was done across cut section of gutta percha/sealer-dentine to detect resin infiltration. Indentation of mechanical properties was evaluated using a Berkovich indenter. The contact angle of irrigants and surface free energy were evaluated. Mineralization nodules were detected through Alazarin red after 14 days.ResultsControl biofilms showed dense green colonies. Majority of E. faecalis bacteria were present in biofilm fluoresced red in NaOCl + 2% QAS group. There was reduction of 484 cm⁻¹ Raman band and its intensity reached lowest with NaOCl + 2% QAS. There was an increase in 1350–1420 cm⁻¹ intensity in the NaOCl + 2% CHX groups. Gradual decrease in 1639 cm⁻¹ and 1609 cm⁻¹ Raman signal ratios were seen in the resin-depth region of 17 μm>, 14.1 μm> and 13.2 μm for NaOCl + 2% QAS, NaOCl + 2% CHX and control groups respectively. All obturated groups showed an intact sealer/dentine interface with a few notable differences. 0.771 and 83.5% creep indentation distance for NaOCl + 2% QAS ultrasonic groups were observed. Highest proportion of polar component was significantly found in the NaOCl + 2% QAS groups which was significantly higher as compared to other groups. Mineralized nodules were increased in NaOCl + 2% QAS.SignificanceFavorable antimicrobial and endodontic profile of the NaOCl + 2% QAS solution might suggest clinical use for it for more predictable reduction of intracanal bacteria.     

High-content analysis for mitophagy response to nanoparticles: A potential sensitive biomarker for nanosafety assessment

Mitophagy, a selective autophagy of mitochondria, clears up damaged mitochondria to maintain cell homeostasis. We performed high-content analysis (HCA) to detect the increase of PINK1, an essential protein controlling mitophagy, in hepatic cells treated with several nanoparticles (NPs). PINK1 immunofluorescence-based HCA was more sensitive than assays and detections for cell viability and mitochondrial functions. Of which, superparamagnetic iron oxide (SPIO)-NPs or graphene oxide-quantum dots (GO-QDs) was selected as representatives for positive or negative inducer of mitophagy. SPIO-NPs, but not GO-QDs, activated PINK1-dependent mitophagy as demonstrated by recruitment of PARKIN to mitochondria and degradation of injured mitochondria. SPIO-NPs caused the loss of mitochondrial membrane potential, decrease in ATP, and increase in mitochondrial reactive oxide species and Ca²⁺. Blocking mitophagy with PARKIN siRNA aggravated the cytotoxicity of SPIO-NPs. Taken together, PINK1 immunofluorescence-based HCA is considered to be an early, sensitive, and reliable approach to evaluate the bioimpacts of NPs.     

马来酸罗格列酮的表面增强拉曼光谱研究

目的:研究马来酸罗格列酮在不同激发光波长以及不同酸碱度条件下的表面增强拉曼光谱,对表面增强拉曼光谱中的分子振动模式进行识别。方法:用3种不同的激发光波长对不同pH条件下马来酸罗格列酮的表面增强拉曼散射(SERS)进行考察,推测分子在纳米颗粒上的吸附取向、成键方式,对增强机制作出推断。结果:研究表明,药物分子-银胶体系的pH对马来酸罗格列酮的增强效应有较大的影响,这是pH对药物分子-银胶体系的凝聚状态和马来酸罗格列酮分子存在状态综合影响的结果。另外,激发光波长对马来酸罗格列酮的SERS效应也有很大的影响,这体现了光源对药物分子-银胶体系的选择性激发。结论:本方法简单、快速、可靠,专属性强,可以作为分析马来酸罗格列酮分子在纳米表面吸附情况的方法。     

振动光谱法研究灯盏花素固体分散体的分散特性

目的:用拉曼和红外光谱法研究灯盏花素固体分散体的分散性,以期获得一种新的简单易行的检查固体分散体分散性的方法。方法:用溶剂法制备灯盏花素固体分散体,用显微共焦拉曼光谱仪、傅里叶变换红外光谱仪和X射线衍射仪分别采集灯盏花素、乙基纤维素(EC)、灯盏花素:EC(1∶3)的物理混合物(PM)以及灯盏花素固体分散体(SDbre)的拉曼图谱、红外图谱和X射线衍射图谱并进行对比分析。结果:灯盏花素以分子状态包埋在EC的网状骨架中,三种方法得到一致的结果。结论:拉曼光谱法快速、直接、对样品无损伤,是一种新的理想的检查固体分散体分散性的方法。     

Characterisation of transmission Raman spectroscopy for rapid quantitative analysis of intact multi-component pharmaceutical capsules

A detailed characterisation of the performance of transmission Raman spectroscopy was performed from the standpoint of rapid quantitative analysis of pharmaceutical capsules using production relevant formulations comprising of active pharmaceutical ingredient (API) and 3 common pharmaceutical excipients. This research builds on our earlier studies that identified the unique benefits of transmission Raman spectroscopy compared to conventional Raman spectroscopy. These include the ability to provide bulk information of the content of capsules, thus avoiding the sub-sampling problem, and the suppression of interference from the capsule shell. This study demonstrates, for the first time, the technique's insensitivity to the amount of material held within the capsules. Different capsules sizes with different overall fill weights (100–400 mg) and capsule shell colours were assayed with a single calibration model developed using only one weight and size sample set (100 mg) to a relative error of typically <3%. The relative root mean square error of prediction of the concentration of API for the main sample set (nominal content 75%, w/w) was 1.5% with a 5 s acquisition time. Models built using the same calibration set also predicted the 3 low level excipients with relative errors of 5–15%. The quantity of API was also predicted (with a relative error within ∼3%) using the same model for capsules prepared with different generations of API (i.e. API manufactured via different processes). The study provides further foundation blocks for the establishment of this emerging technique as a routine pharmaceutical analysis tool, capitalising on the inherently high chemical specificity of Raman spectroscopy and the non-invasive nature of the measurement. Ultimately, this technique has significant promise as a Process Analytical Technology (PAT) tool for online production application.     

醛酮类药用辅料的振动光谱分析

目的:建立醛酮类药用辅料的拉曼光谱分析方法。方法:采集了几种醛酮类药用辅料的红外光谱和拉曼光谱,分别归属其振动光谱峰并分析比较光谱差异与结构之间的关系。结果:和红外光谱一样,拉曼光谱可以给出关于化合物结构的指纹信息,并可和红外光谱相互补充佐证。结论:建立的方法快速、简便、专属性强,可用于醛酮类药用辅料的鉴别。