Novo sistema de aplicação de drogas em cirurgias oftalmológicas

The topical corneal application of antimitotic mitomycin-C (MMC) during refractive surgery is still characterized by a lack of standardization and considerable empirism. For this reason the creation of a system capable of reliable drug delivery represents a beneficial innovation for patients submitted to these procedures. Objective: Elaborate a new MMC delivery system during the transoperatory period of photorefractive keratectomy (PRK) followed by patent application. Methods: The project consists of an in vitro experimental study to create an MMC (0.02%) release system. The drug was impregnated in sterile Whatman® 41 paper filter discs with a diameter of 8 mm. After drying, the discs were applied to antibiogram plates seeded with Staphylococcus epidermidis (American Type Culture Collection ATCC 12228), followed by the addition of a drop of sterile water. At the end of 1 minute, the discs were removed and the plates incubated for 48 hours at 35oC. Mean drop volume in the collyrium flasks was measured using analytical balance weighing. The inhibition halo (mm) was correlated with the MMC impregnated into the disc. After completion of the invention design a patent application was lodged at the National Institute of Industrial Property. Results: The correspondence between MMC-produced inhibition halos indicated that a dose of 16μg was ideal for impregnating into the discs. The mean drop volume obtained from the collyrium flasks was 37.7 μL. A minute after the application of one drop of balanced saline solution, the system released an adequate concentration for PRK surgery. Conclusion: A new MMC delivery system was created for transoperatory application in photorefractive keratectomy (PRK). Publication of the patent application (number PI 0704739-8) gives the authors exclusive intellectual property rights. The study was sponsored by Ophthalmos Indústria e Comércio de Produtos Farmacêuticos S.A. (São Paulo-SP, Brazil) and received the indispensable scientific contribution of researchers from the fields of Pharmacy, Medicine, Biology, Statistics and Law, characterizing the work as multidisciplinary, in accordance with norms established by the Postgraduate Health Sciences Program of the Federal University of Rio Grande do Norte (UFRN)

Desgaste corrosivo-cavitativo-erosivo de um aço-carbono em meio aquoso com frações de sal (NaCl), CO2 e particulados sólidos (SiO2)

A batch of eighty-four coupons of low carbon steel were investigated at laboratory conditions under a corrosive, cavitative-corrosive (CO2) and corrosive-erosive (SiO2 + CO2) in an aqueous salt solution and two levels of temperature. The following measurements were made on Vickers (HV0,05, HV0,10, HV0,20) Microhardness tests at three levels of subsurface layer. A turbulent flow collided on the cylindrical sample, with and without mechanical stirring and gas bubbling, with and without fluid contamination by solid particles of SiO2, at two temperatures. Surface Roughness and Waviness, under two conditions "as received, after machining" and "after worn out", as well as gravimetric and electrochemical parameter were measured on the two opposite generatrices of each cylindrical sample, on the flow upstream (0°) and downstream (180°) by Profilometry, Mass Variation and Linear Polarization Resistance (LPR). The results of the Microhardness and Surface Texture of all coupons were subjected to statistical comparison, using the software Statgraphics® Centurion XVI, 95% statistical certainty, and significant differences were observed in some arrays of measurements. The corrosive wear rate measured by LPR and mass variation shown to be sensitive to the presence of bubbles and hydrodynamic fluctuations inside the cell, considering the temperature and contamination of corrosive fluid by solid particles. The main results of visual inspection relative to some topologies of the surface damages involving different mechanisms that were seen to give explanation for some fluctuations in wear rates of the steel experimentally investigated