Home About us Contact
|
Home About us Contact | ||
|
|
||
Porcine Skin (porcine + skin)
Selected AbstractsA Comparison of Four Mohs Tissue Preparation Methods Using Porcine SkinDERMATOLOGIC SURGERY, Issue 9 2010FRCPC, WILLIAM LEAR MD OBJECTIVE Mohs surgery relies on high-quality, rapid tissue preparation and processing. This study evaluated four currently performed tissue preparation and processing methods for speed of processing and depth of cut into the tissue block to achieve a complete high-quality section. METHODS The following four methods were tested: cryoEMBEDDER, float, heat sink, and slide. Standardized specimens of porcine skin were used to ensure uniformity. We measured the time required for a technician to flatten, embed, and cut to the first complete section of each specimen. Additionally, we measured the depth in microns required to cut into an embedded specimen to achieve a complete section. RESULTS There were advantages and disadvantages of each method, and our findings suggest that the heat sink and float methods are more time efficient but that the slide and cryoEMBEDDER methods require less cutting into the specimen to obtain a complete section. The cryoEMBEDDER device used in this study was loaned by cryoEMBEDDER (Salt Lake City, Utah). [source] Synthesis and characterization of injectable bioadhesive hydrogels for nucleus pulposus replacement and repair of the damaged intervertebral discJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2010J. Vernengo Abstract Bioadhesive polymers are natural or synthetic materials that can be used for soft tissue repair. The aim of this investigation was to develop an injectable, bioadhesive hydrogel with the potential to serve as a synthetic replacement for the nucleus pulposus of the intervertebral disc or as an annulus closure material. Branched copolymers of poly(N -isopropylacrylamide) (PNIPAAm) and poly(ethylene glycol) (PEG) were blended with poly(ethylene imine) (PEI). This three component injectable system can form a precipitated gel at physiological temperature due to the phase transition of PNIPAAm. The injection of glutaraldehyde into the gel core will adhere the implant to the surrounding tissues. 1H NMR results indicated the successful physical incorporation of PEI into the PNIPAAm-PEG network by blending. In addition, the covalent crosslinking between the amine functionalities on the PEI and the aldehyde functionalities on the glutaraldehyde was verified using FTIR difference spectroscopy. Mechanical characterization of these blends showed a significant increase (p < 0.05) in compressive modulus following glutaraldehyde injection. The in vitro bioadhesive force studies with porcine skin showed a significant increase (p < 0.05) in the mean maximum force of detachment for PNIPAAm-PEG/PEI gels when glutaraldehyde was injected into the gel core. The results of this study indicate that the reactivity between amines and aldehyde functionalities can be exploited to impart bioadhesive properties to PNIPAAm-PEG/PEI copolymers. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [source] Design of improved permeation enhancers for transdermal drug deliveryJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2009Srinivas S. Godavarthy Abstract One promising way to breach the skin's natural barrier to drugs is by the application of chemicals called penetration enhancers. However, identifying potential enhancers is difficult and time consuming. We have developed a virtual screening algorithm for generating potential chemical penetration enhancers (CPEs) by integrating nonlinear, theory-based quantitative structure,property relationship models, genetic algorithms, and neural networks. Our newly developed algorithm was used to identify seven potential CPE molecular structures. These chemical enhancers were tested for their toxicity on (a) mouse embryonic fibroblasts (MEFs) with MTT assay, and (b) porcine abdominal skin by histology using H/E staining at the end of a 48-h exposure period to the chemicals. Further, melatonin permeability in the presence of the enhancers was tested using porcine skin and Franz diffusion cells. Careful toxicity tests showed that four of the seven "general" CPEs were nontoxic candidate enhancers (menthone, 1-(1-adamantyl)-2-pyrrolidinone, R(+)-3-amino-1-hydroxy-2-pyrrolidinone, and 1-(4-nitro-phenyl)-pyrrolidine-2,5-dione). Further testing of these four molecules as potential melatonin-specific CPEs revealed that only menthone and 1-dodecyl-2-pyrrolidinone provided sufficient enhancement of the melatonin permeation. The results from our permeability and toxicity measurements provide validation of the efficacy and ability of our virtual screening algorithm for generating potential chemical enhancer structures by virtual screening algorithms, in addition to providing additional experimental data to the body of knowledge. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4085,4099, 2009 [source] Multinuclear NMR characterisation and dermal delivery of fluorinated drugs in soybean-microemulsion systemsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2009Sonja Hoeller Abstract The present study evaluated the effect of different commercially available soybean lecithins in microemulsion systems in terms of microstructure transformation, physicochemical properties and transport of selected entrapped fluorinated drugs through skin. Physicochemical characterisations by particle size and polydispersity index (PDI) measurements were performed and a direct correlation with NMR self-diffusion coefficients of the individual components was found. An increase of lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) in the phospholipid mixtures increased the mean particle sizes and PDI. Bicontinous microemulsion structures were proven by 1H and 31P NMR in the placebo microemulsions. Reasonable permeation of the lipophilic drugs of all microemulsions systems was confirmed in standard diffusion studies using porcine skin. This could be due to the incorporation of the drugs in the surfactant structure of the lecithin based bicontinous micro textures, as proven by 19F NMR self-diffusion studies. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2686,2695, 2009 [source] Tocopheryl acetate disposition in porcine and human skin when administered using lipid nanocarriersJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2010Mojgan Moddaresi Abstract Objectives Assessing the delivery of a drug into the skin when it has been formulated within a nanocarrier is a complex process that does not conform to the conventions of traditional semi-solid formulations. The aim of this study was to gain a fundamental understanding of drug disposition in both human and porcine skin when applied using a lipidic nanocarrier. Methods A model system was generated by loading tocopheryl acetate into a well-characterised solid lipid nanoparticle and formulating this system as a traditional aqueous hyaluronic acid gel. Franz diffusion cells fitted with a silicone or nylon membrane were used to assess drug and particle transport independently whilst human and pig skin were employed to determine skin delivery. Key findings The tocopheryl acetate, when loaded into the solid lipid nanoparticles, did not release from the particle. However, 1.65 ± 0.90% of an infinite dose of tocopheryl acetate penetrated into the stratum corneum of pig skin when delivered using a nanoparticle-containing gel. Conclusions These results suggest that hydration of the stratum corneum in pig skin could lead to the opening of hydrophilic pores big enough for 50 nm-sized particles to pass into the superficial layers of the skin, a phenomenon that was not repeated in human skin. [source] In-vitro permeation of drugs into porcine hair follicles: is it quantitatively equivalent to permeation into human hair follicles?JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2008Yakov Frum It is already well-established that the general permeability properties of porcine skin are close to those of human skin. However, very little is known with respect to drug absorption into hair follicles and the similarities if any between the two types of tissue. The aim of this study was to use the skin sandwich system to quantify follicular drug absorption into porcine hair follicles. To our knowledge, this is the first time that the skin sandwich has been extended to porcine tissue. For this purpose, seven different drugs , estradiol, corticosterone, hydrocortisone, aldosterone, cimetidine, deoxyadenosine and adenosine , exhibiting a wide range of log octanol-water partition coefficients (log Ko/w), but comparable molecular weights, were chosen as candidate solutes. The results showed a parabolic profile with maximal follicular contribution occurring at intermediate log Ko/w values. Linear regression analysis indicated that the follicular contributions in porcine skin correlated well with previously published follicular contributions in human skin (r2 = 0.87). The novelty of this research is that we show that porcine tissue is a good surrogate for modelling human skin permeability within the specific context of quantifying drug absorption into hair follicles. [source] Estimation of the relative antiinflammatory efficacies of six commercial preparations of Harpagophytum procumbens (Devil's Claw)PHYTOTHERAPY RESEARCH, Issue 3 2010Nassima Abdelouahab Ouitas Abstract The current work compared the relative efficacies of six commercial formulations of H. procumbens. Each formulation was assayed for the content of harpagoside (1), harpagide (2), verbascoside (3) and 8- O-p -coumaroyl harpagide (4) and, based on the recommended dosages, the total daily amounts were determined and used to establish anti-/proinflammatory (A/P) factors. The formulations were compared using ex vivo porcine skin for their activities towards COX-2 by Western blotting. The results showed great variation in the amounts of compounds 1,4 within the six formulations examined. The relative proportions of 1,4 also varied widely between the products and this inconsistency was reflected in the A/P factors, which correlated with the COX-2 expression (R2 = 0.9496). Although the data support the beneficial antiinflammatory effects from the use of some of the brands tested, others would appear potentially to exacerbate inflammation. To conclude, a ratio based upon the amount and relative proportions of anti- and proinflammatory compounds can be used to predict relative antiinflammatory properties. Also, with access to a diversity of ostensibly similar commercial products, the patient may experience varying therapeutic responses. Finally, current pharmacopoeia monographs, which are generally concerned with a minimum harpagoside content, are inadequate for ensuring the quality of products based on H. procumbens. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||