Home About us Contact
|
Home About us Contact | ||
|
|
||
Confocal Raman Microscopy (confocal + raman_microscopy)
Selected AbstractsConfocal Raman Microscopy as a Tool to Investigate Concentration Profiles of Melt Crystallized Ibuprofen/Carnauba WaxCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2009H. Qu Abstract Coatings are of great significance for pharmaceutical solid dosage forms. They fulfil a number of functions and are often necessary to control drug delivery, to mask bitter taste, or to protect the active pharmaceutical ingredient from detrimental environmental factors. The process of self-coating by melt crystallization of a suitable binary mixture eliminates the need for an additional process step in the manufacture of a solid drug. Self-coating relies upon the physical and spatial separation of individual components in a melt during solidification. This paper focuses on the use of confocal Raman microscopy as a nondestructive technique for quantifying the spatial distribution of the components in self-coated pastilles manufactured from the binary system ibuprofen/carnauba wax. Pastilles are produced from the melt. Raman spectroscopy allows the direct analysis of concentration profiles across the surface of the pastille. Here, the samples are cleaved and the cleaved surface is investigated in order to establish the distribution of the components in the interior of the solid. A univariate calibration model was developed and statistically validated with standard mixtures of ibuprofen and carnauba wax. Different regression models (linear or polynomial, using different significant peaks for the respective compounds) were assessed and a linear model was found to be adequate to determine the concentration gradient in the pastilles. [source] Fabrication of a Macroporous Microwell Array for Surface-Enhanced Raman ScatteringADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Martina Zamuner Abstract Here, a colloidal templating procedure for generating high-density arrays of gold macroporous microwells, which act as discrete sites for surface-enhanced Raman scattering (SERS), is reported. Development of such a novel array with discrete macroporous sites requires multiple fabrication steps. First, selective wet-chemical etching of the distal face of a coherent optical fiber bundle produces a microwell array. The microwells are then selectively filled with a macroporous structure by electroless template synthesis using self-assembled nanospheres. The fabricated arrays are structured at both the micrometer and nanometer scale on etched imaging bundles. Confocal Raman microscopy is used to detect a benzenethiol monolayer adsorbed on the macroporous gold and to map the spatial distribution of the SERS signal. The Raman enhancement factor of the modified wells is investigated and an average enhancement factor of 4,×,104 is measured. This demonstrates that such nanostructured wells can enhance the local electromagnetic field and lead to a platform of ordered SERS-active micrometer-sized spots defined by the initial shape of the etched optical fibers. Since the fabrication steps keep the initial architecture of the optical fiber bundle, such ordered SERS-active platforms fabricated onto an imaging waveguide open new applications in remote SERS imaging, plasmonic devices, and integrated electro-optical sensor arrays. [source] A coordinated approach to cutaneous wound healing: vibrational microscopy and molecular biologyJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 5b 2008K. L. Andrew Chan Abstract The repair of cutaneous wounds in the adult body involves a complex series of spatially and temporally organized processes to prevent infection and restore homeostasis. Three characteristic phases of wound repair (inflammation, proliferation including re-epithelialization and remodelling) overlap in time and space. We have utilized a human skin wound-healing model to correlate changes in genotype and pheno-type with infrared (IR) and confocal Raman spectroscopic images during the re-epithelialization of excisional wounds. The experimental protocols validated as IR images clearly delineate the keratin-rich migrating epithelial tongue from the collagen-rich wound bed. Multivariate statistical analysis of IR datasets acquired 6 days post-wounding reveal subtle spectral differences that map to distinct spatial distributions, which are correlated with immunofluorescent staining patterns of different keratin types. Images computed within collagen-rich regions expose complementary spatial patterns and identify elastin in the wound bed. The temporal sequence of events is explored through a comparison of gene array analysis with confocal Raman microscopy. Our approach demonstrates the feasibility of acquiring detailed molecular structure information from the various proteins and their subclasses involved in the wound-healing process. [source] Development of clinical dosage forms for a poorly water-soluble drug II: Formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drugJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2009Ping Li Abstract The solution of a poorly water-soluble drug in a liquid lipid,surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 µg/mL at pH 1,8 and 25°C) was dissolved in a melt of the mixture at 65,70°C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55°C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55,60°C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (<150 nm) and the presence of PEG 3350 did not interfere with the process of self-microemulsification. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1750,1764, 2009 [source] Detection of explosives on human nail using confocal Raman microscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2009Esam M. A. Ali Abstract Trace amounts of explosives were detected on human nail using confocal Raman microscopy. Contamination of the nail can result from the manual handling, packaging or transportation of explosive substances. Raman spectra were obtained from pentaerythritol tetranitrate (PETN), trinitrotoluene (TNT), ammonium nitrate and hexamethylenetetramine (HMTA) particles on the surface of the nail with dimensions in the range 5,10 µm. An added difficulty in an analytical procedure is the presence of a nail varnish coating that has been applied, which traps the particulate matter between the coating and nail. Using confocal Raman microscopy, interference-free spectra could be acquired from particles of explosives visually masked by the nail varnish. Spectra of the explosives could be readily obtained in situ within 90 s without alteration of the evidential material. Acquisition of a Raman point map of a PETN particle under the nail varnish coating is also reported. Copyright © 2008 John Wiley & Sons, Ltd. [source] Confocal Raman Microscopy as a Tool to Investigate Concentration Profiles of Melt Crystallized Ibuprofen/Carnauba WaxCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2009H. Qu Abstract Coatings are of great significance for pharmaceutical solid dosage forms. They fulfil a number of functions and are often necessary to control drug delivery, to mask bitter taste, or to protect the active pharmaceutical ingredient from detrimental environmental factors. The process of self-coating by melt crystallization of a suitable binary mixture eliminates the need for an additional process step in the manufacture of a solid drug. Self-coating relies upon the physical and spatial separation of individual components in a melt during solidification. This paper focuses on the use of confocal Raman microscopy as a nondestructive technique for quantifying the spatial distribution of the components in self-coated pastilles manufactured from the binary system ibuprofen/carnauba wax. Pastilles are produced from the melt. Raman spectroscopy allows the direct analysis of concentration profiles across the surface of the pastille. Here, the samples are cleaved and the cleaved surface is investigated in order to establish the distribution of the components in the interior of the solid. A univariate calibration model was developed and statistically validated with standard mixtures of ibuprofen and carnauba wax. Different regression models (linear or polynomial, using different significant peaks for the respective compounds) were assessed and a linear model was found to be adequate to determine the concentration gradient in the pastilles. [source] | ||||||||||