Simple Pharmanotes

Novel drug delivery system is an advanced drug delivery system targeting the modification of drug release, site specificity, improved drug absorption, reduced side effect profile and increased patient compliance toward the dosage form. Hence novel drug delivery systems can provide a new life to the drug molecule. Use of Herbal Drugs is increasing worldwide with reference to their effectiveness with lower side effect profiles over their allopathic counterparts. India is home to “Ayurveda” have more scope as well as demand for the herbal formulations. However the current herbal formulations lack in several areas like, Improper absorption. ( Mostly due to interaction with other substances and partial deactivation by acid/enzymes or by both). Decreased patient compliances. ( Conventional dosage forms are not modified for aesthetic properties like colour, odour, taste etc.). Fluctuations in drug plasma level. Pre-systemic metabolism. Accumulation of drug at non-targeted sites.

Transfer of Drug Molecules Across the Biological Barriers. For systemic absorption, a drug must pass from the absorption site through one or more layers of cells to gain access to the general circulation. For absorption into the cells, a drug must traverse the cell membrane. STRUCTURE OF CELL MEMBRANE Cell membrane surrounds the entire cells and acts as a boundary between the cell and interstitial fluid.  Cell membrane acts as a selective barrier to the passage of molecules. Water, some small molecules, and lipid-soluble molecules pass through such membrane; whereas highly charged molecules and large molecules, such as proteins and protein-bound drugs, can not. Structure Cell membranes are generally thin, approximately 70 to 100 Å  in thickness.  They are primarily composed of phospholipids in the form of a bilayer .  Some carbohydrates and proteins are interspersed within this lipid bilayer. Lipid bilayer or Unit membrane theory (Proposed by Dav

Fibers CLASSIFICATION : Vegetable origin – cotton, jute Animal origin – wool, silk Mineral origin – asbestos, glass wool Synthetic origin – nylon, terylene Regenerated from cellulose – rayon Regenerated from protein – milk protein, groundnut COTTON / RAW COTTON: BIOLOGICAL SOURCE:  Trichomes of seeds of cultivated species of Gossypium herbaceum Family: Malvaceae GEOGRAPHICAL SOURCE: I ndia, Egypt Collection: The capsule of cotton consists contains large number of seeds covered with trichomes The trichomes are separated Long trichomes are used in preparation of fabric & short ones are used in preparation of surgical dressings This non-absorbent cotton, when treated with dilute soda solution for 10 to 15 hours at a higher pressure, gets free of fats. The resulting absorbent cotton is dried, sterilized with gamma radiation Description: White, soft to touch Chemical Tests: ABSORBENT COTTON: Fibre when treated with N/50 iodine solution