الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Skin is the largest organ of the human body. It performs several functions such as; defensing the body against the entry of chemicals and microorganisms, providing a barrier to the loss of fluids and salts as well as helping in regulation of body temperature. The large surface area of the skin makes it a potentially interesting route for drug delivery.
sing nanosystems in skin delivery for therapeutic, diagnostic, prophylactic or cosmetic substances has shown great interest in pharmaceutical field. The ultimate goal is to overcome the skin barrier in a controlled manner to reach targets in various skin layers, including the stratum corneum, as well as deeper tissues, or even for systemic use.
Millions around the world suffer from acute and chronic wounds. Treatment becomes a major health issue. The main objective in the management and treatment of wounds is to achieve quick healing of the skin. chronic, non-healing neuropathic foot ulcers occur in about 15% of all the diabetic patients. Neuropathy and vasculopathy are the main factors for delayed wound healing process in diabetic patients.
<Wound dressings represent a very important segment in the medical and pharmaceutical wound care system. Their role is to keep the wound dry by allowing evaporation of wound exudates and preventing entry of harmful bacteria into the wound surface. It has now been shown, that having a warm moist wound environment, effective oxygen circulation around the wound achieve more rapid and successful wound healing process.
<Wafers are a relatively novel formulations produced by freeze-drying (lyophilization) of polymer solutions and gels to yield solid porous structures that can easily be applied to exuding wound surfaces. Wafers for wound healing drug delivery offer several advantages such as maintaining moist environment and absorption of large amount of wound exudates due to their high porosity. After application to the wound surface, lyophilized wafers revert to highly viscous fluids or resilient gels upon the absorption of exudate. Thus, ensuring longer in situ residence time if the balance between fluid absorption and moisture loss is maintained in addition to providing sustained release of the drug.
<Considerable attention has been focused on the development of novel drug delivery systems based on herbal drugs as they have enormous therapeutic potential. Diosmin has been chosen as a model drug for the current study. Diosmin is characterized by poor water solubility, pH dependent solubility and practically insoluble in most organic solvents. Diosmin possess strong anti-inflammatory and anti-oxidant properties so its topical administration will be promising. On the other hand, it is a challenging drug due to its low permeation through skin due to its unfavorable physicochemical properties.
<So, the current work aimed to develop and characterize diosmin nanocrystals by using simple technique with low cost (anti-solvent precipitation). Evaluation of different stabilizers with different concentrations to achieve the most stable nanocrystals was assessed. In addition, converting diosmin nanosuspension into a more stable dry form by lyophilization was also evaluated.