Simple Pharmanotes

  Introduction. Niosomes are a novel drug delivery system that encapsulates the medication in a vesicular system made up of non ionic surfactants.  The vesicle is made up of a bilayer of non-ionic surfactants , thus the name niosomes. Niosomes are extremely small and microscopic (on a nanometric scale).  Despite having a similar structure to liposomes , they have several advantages over them.  Advantages of Niosomes. The vesicles may act as a depot, releasing the drug in a controlled manner.  They are osmotically active and stable, and also they increase the stability of entrapped drugs.  They improve the therapeutic performance of the drug molecules by delayed clearance from the circulation, protecting the drug from biological environment and restricting effects to target cells.  The surfactants used are biodegradable, biocompatible and nonimmunogenic.  They improve oral bioavailability of poorly absorbed drugs and enhance skin penetration of drugs.  They can be made to reach the s

  Introduction. Liposome was first discovered in the early 1965 by Alec D. Bangham . Liposome word is derived from two Greek words, Lipo: Fatty. + Soma: Body= Hence literally it means a lipid body.   They are relatively small in size and it ranges from 50 nm to several micrometers in diamete r.  They are spherical vesicles in which an aqueous core is entirely enclosed by one or more phospholipid bilayers.  It has the unique ability to entrap both lipophilic and hydrophilic compounds.  The hydrophobic or lipophilic molecules are inserted into the bilayer membrane, whereas hydrophilic molecules can be entrapped in the aqueous center .  Because of their biocompatibility, biodegradability, low toxicity, and aptitude to trap both hydrophilic and lipophilic drugs they simplify site-specific drug delivery to tumor tissues, being so versatile they have emerged as a prominent Targeted drug delivery system. ADVANTAGES OF LIPOSOMES. Hydrophobic (e.g., amphotericin B), hydrophilic (e.g., cytara

  Introduction. Targeting drugs to specific cells and tissues of the body without allowing them to enter the systemic circulation is an innovative concept.  The drug can be given in such a way that it reaches the receptor site in sufficient concentration without disrupting an extraneous tissue cell .   These products are created by taking into account: Specific properties of the target cells. Nature of markers or transport carriers or vehicles which convey drugs to specific receptors. Ligands and physically modulated compounds.   Important Properties Influencing Drug Targeting: The general properties influencing drug targeting can be divided into three broad categories, such as drug, carrier, and in vivo environment properties. Drug: Concentration,  Particulate location and Distribution  Molecular Weight,  Physicochemical properties  Drug Carrier Interaction. Carrier: Type and Amount of Excipients  Surface Characteristics,  Size  Density In vivo environment properties: pH,  Polarity,