Posted by admin on Jul 1, 2012 in |
Ocular inserts are sterile preparations, with a thin, multilayered, drug-impregnated, solid or semisolid consistency devices placed into cul-de-sac or conjunctiva sac. They are usually made up of polymeric vehicle containing drug. Ocular drug delivery is one of the most fascinating and challenging tasks being faced by the Pharmaceutical researchers. One of the major barriers of ocular medication is to obtain and maintain a therapeutic level at the site of action for prolonged period of time. The therapeutic efficacy of an ocular drug can be greatly improved by prolonging its contact with the corneal surface. Newer ocular drug delivery systems are being explored to develop extended duration and controlled release strategy. Some of the newer, sensitive and successful Ocular delivery systems like inserts, biodegradable polymeric systems, and collagen shields are being developed in order to attain better ocular bioavailability and sustained action of ocular...
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Posted by admin on Jul 1, 2012 in |
Topical administration of a drug in the conjunctival cul-de-sac is the treatment of choice for diseases of the anterior segment of eye. Development of ophthalmic drug delivery systems has always been challenging because of the drawbacks with this route, like non-productive absorption, drainage, induced lacrimation, tear turn over, impermeability of drugs to cornea. New approaches have been investigated for delivery of drugs to the eye by means of polymeric delivery of ophthalmic drugs to the pre-and intra ocular tissues, have been attempted to increase the bioavailability and the duration of therapeutic action of ocular drug. Certain new approaches to increase the ocular bioavailability, duration of the drug action and to reduce the undesirable side effects are by using drug carriers that regulate pre-corneal drug loss and improve the corneal contact time. Many of these systems prolong ocular bioavailability but do not control drug penetration through the cornea. Consequently, the drug concentration at the site of action might remain inadequate. Therefore, it is necessary to develop safer, efficacious and more...
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Posted by admin on Jul 1, 2012 in |
Crinum is an important Amaryllidaceous plant thanks to the valuable biological and therapeutic activities of its chemical constituents, especially alkaloids. Many Crinum species have been commonly used in traditional medicines worldwide. Long ago, they have been subjected to extensive chemical, cytological and pharmacological investigations. Accordingly, this work comprehensively comprises both the alkaloidal and non-alkaloidal principles of Crinums isolated from 1950 and up to now, together with various biological and toxicological studies conducted on both the total extracts and individual compounds. As being a major common class of Crinum alkaloids, the current part of this review work highlights the lycorine-type alkaloids isolated so far from this plant in addition to their distribution in different Crinum...
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Posted by admin on Jul 1, 2012 in |
A supercritical fluid (SF) can be defined as a dense non condensable fluid. A fluid reaches the supercritical status when its temperature and pressure exceed the relevant critical temperature and pressure. At the critical point only a single phase exists which has some properties typical of liquids (density) and some of gases (viscosity, compressibility, and mass diffusion coefficient). For pharmaceutical applications, the most widely used SF is carbon dioxide (more than 98% of the applications have been developed using this fluid) because of its low and easily accessible critical temperature (31.2◦C) and pressure (7.4MPa), non-flammability, non-toxicity and inexpensiveness. The physical and thermal properties of SCFs fall between those of the pure liquid and gas. SCFs offer liquid-like densities, gas-like viscosities, gas-like compressibility properties and higher diffusivities than liquids. The properties of SCFs, such as polarity, viscosity, and diffusivity, can be altered several-fold by varying the operating temperature and/or pressure during the process. This flexibility is enabling the use of SCFs for various applications in the food and pharmaceutical industries,...
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Posted by admin on Jul 1, 2012 in |
This work has an innovative approach for the development of biological nanorobots with sensors for medicine. The biological nanorobots operate in a virtual environment based on random, thermal and chemical control techniques. The biological nanorobot architecture model has biological nano bioelectronics as the basis for manufacturing integrated system devices with embedded biological nano biosensors and actuators, which facilitates its application for medical target identification and drug delivery. The biological nanorobot interaction with the described workspace shows how these biological nanorobots detect the target area and supply the drug. Therefore, our work addresses the control and the architecture design for developing practical molecular machines. Advances in nanotechnology are enabling manufacturing nanosensors and actuators through nano bioelectronics and biologically inspired devices. Analysis of integrated system modeling is one important aspect for supporting nanotechnology in the fast development towards one of the most challenging new fields of science: molecular machines. The use of 3D simulation can provide interactive tools for addressing nanorobot choices on sensing, hardware architecture design, manufacturing approaches, and control...
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