The purpose of this study is to monitor in vivo the delivery of trans-retinol into human skin. Delivery to real systems, such as skin, can be extremely difficult to execute and is problematic to confirm and measure. So far, methods for studying the delivery of compounds through the skin are mostly ex vivo and so inherently influence the skin and may not translate directly to the in vivo situation. Raman spectroscopy is uniquely placed to be able to measure biological processes in vivo, and this paper shows that the trans-retinol penetration into the skin can successfully be measured in vivo using this technique. This study measured the volar forearm of volunteers treated with 0.3% trans-retinol in propylene glycol (PG)/ethanol and 0.3% trans-retinol in caprylic/capric acid triglyceride (MYRITOL318), an oil found in skin creams. Solutions were applied and then confocal Raman depth profiles were obtained of the stratum corneum (SC) and into the viable epidermis (VE) up to 10 hours after treatment. Remarkable differences between a penetrating and a nonpenetrating solution can clearly be observed. Treating with trans-retinol in PG/ethanol results in trans-retinol penetrating through the SC and into the VE. Its penetration was also observed to be highly correlated with the depth of penetration of the PG, which is well known as an efficient penetration enhancer. In contrast, while treating with trans-retinol in MYRITOL318, trans-retinol hardly penetrates at all. For the first time, the penetration of trans-retinol has been monitored directly after application of solutions, in vivo without skin excision. Here, the effect of two different solutions on the delivery of trans-retinol into the skin was measured very effectively in vivo by Raman spectroscopy.

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The prediction of percutaneous absorption and bioavailability in vivo, using the recently reported "bricks-and-mortar" model is discussed. Two sets of in vivo data have been simulated: the tape-striping data of 4-cyanophenol and Raman spectrometry data of transretinol. The predicted transdermal permeation using theoretically derived properties agreed well with the experimental data. The prediction shows that about 2/3 of the 4-cynophenol in the SC partitioned into the corneocytes, indicating diffusion of moderately hydrophobic solutes across the corneocytes is also important. Only for highly hydrophobic solute like transretinol, diffusion across the corneocytes is negligibly small. The study demonstrates that with the mechanism-based computer model, many dermatopharmacokinetic parameters can be derived, providing much insight into how vehicle formulation and topical administration affects the absorption and distribution of solute in the SC, as well as its bioavailability in epidermis/dermis. © 2010 American Institute of Chemical Engineers (AIChE)

Flexible pipes are made up of several different layers specifically designed to meet the requirements of our clients and API17J / ISO13628-2. In the pursuit of ever more efficient and reliable solutions, even in the world’s harshest and deepest offshore environments, TECHNIP’s R&D activity is focused on extending its product range by introducing new products and materials. As part of this innovation program, new polymers are constantly being investigated to assess their potential as a pressure sheath. The pressure sheath is the most critical thermoplastic sheath within the structure. Its role is to contain internal fluid and transfer internal pressure to the pressure vault layer outside it. To fulfill that mission, this polymer must be leakproof and perform over wide temperature and pressure range. In operation condition, the presence of small flaws within the pressure sheath could propagate leading to failure and significant environmental and operational damages. Therefore, the manufacturing of such a polymer layer must conform with ever-higher levels of reliability and quality. This is the reason why a visual inspection of pressure sheath according to API17J / ISO13628-2 standards is mandatory. As a leitmotiv, TECHNIP dedicates a lot of effort, not only to extend the limits of the possible by introducing new materials, but also to take inspection further beyond standard requirements by developing dedicated on-line NDT control systems able to ensure layer high quality. Many people are familiar with the medical applications of ultrasonic imaging in which ultrasonic waves are used to create highly detailed cross-sectional pictures of internal organ. Medical echography is commonly performed with specialized multielement probe known as phased-array and their accompanying hardware and software. The applications of ultrasonic phased-array technology are not limited to medical diagnosis and in recent years, increasing use of these systems can be observed in industrial environment. Nevertheless, although phased-array systems on the market can provide new levels of information and visualization, they are manually and locally operated and are inappropriate to control polymer sheath over several kilometers during manufacturing. This paper presents a specific and automated ultrasonic system dedicated to manufacturing control of thermoplastics such as the pressure sheath. Developed by TECHNIP, and based on cutting edge ultrasonic technology used in aerospace and medicine, OPUS is a world-class NDT system able to prove that our pressure sheaths meet design criteria and achieve the highest quality level.