Liposomes

A liposome is a microscopic vesicle consisting of an aqueous core enclosed in one or more phospholipid layers, used to convey vaccines, drugs, enzymes, or other substances to target cells or organs. Liposomes are bilayered structures made of amphipathic (both hydrophobic and hydrophilic) phospholipids/cholesterol that spontaneously form closed structures when hydrated in aqueous solutions. Liposomes are acceptable and superior carriers having ability to encapsulate hydrophilic and lipophilic drugs and protect them from degradation. Topical liposomes have similarity to biological membranes they can store water-soluble and lipophilic substances in their different phases. Moreover, they are similar to the epidermis with respect to their lipid composition, which enables them to penetrate the epidermal barrier to a greater extent compared to other dosage forms. According to studies performed so far liposomes are biodegradable and non-toxic. The really new aspect with liposomes is that they are thought to act not only as drug transporters but also drug localizers. Thus vehicles can transport drugs to the wanted site of action within the skin by preventing systemic absorption and consecutively unwanted effects. The liposomal semisolid formulations could perform therapeutically better effects than the conventional formulations, as prolonged and controlled release topical dosage forms, which may lead to improved efficiency and better patient compliance. Such review giving an emphasis on topically applied liposomal formulations which encompasses methods of preparation, evaluation, mechanisms for enhancement in drug delivery through the skin and regulatory requirements necessitates as topical dosage form.

Azacitidine and its deoxy derivative are used in the treatment of myelodysplastic syndrome. These types of drugs were first synthesized in Czechoslovakia as potential chemotherapeutic agents for cancer. Conventional compositions of Azacitidine are available as powder product or as a solution of Azacitidine in water. Both these products have been associated with a number of toxicities when administered intravenously. To overcome these problems, in the present study, inclusion of Azacitidine in liposomal formulation has proved to be good approach to eliminate the toxicities and improve drug antitumor activity. We formulated Azacitidine liposomes containing Hydrogenated soy phosphatidylcholine, 1,2-Distearoyl-sn-glycero-3[Phospho-rac-(1-glycerol ) (Sodium Salt) [DSPG-Na] and Cholesterol by dried thin film hydration technique. Particle size analysis, zeta potential, %free drug are strongly affected by the different lipid concentration and result shown F5 formulation have the optimum % free drug, Particle size and F2 formulation shown highest Percent drug release when compared to the F4 & F5 formulations. The release kinetics of F2, F4 and F5 formulations were studied. All the formulations follow zero-order release kinetics and follow case-II transport when it applied to the Korsmeyer-Peppas model for the mechanism of drug release. The stability of the F2, F4 & F5 formulations were studied at 5±3oc and at room temperature for duration of 3 months. Hence it can be concluded that the liposomes along with Hydrogenated soy phosphatidylcholine, DSPG-Na and Cholesterol are suitable carriers for the preparation of Azacitidine liposomes. Key words: Azacitidine, Liposomes, Hydrogenated soy phosphatidylcholine, 1,2-Distearoyl-sn-glycero-3[Phospho-rac-(1-glycerol.) [DSPG-Na], cholesterol.

Osteoarthritis (OA) is a group of chronic, painful, disabling condition affecting synovial joints. OA is the most common among elderly people. Approximately 80% of population above 65 years of age suffers from OA and this value reaches near to 100% with increasing age. Currently available treatments of OA provide symptomatic relief or slow the progression of disease. The oral or parenteral administration of these drugs causes serious systemic side effects leading to even withdrawal of certain drugs from market. To overcome these problems, localized IA drug delivery presents a new hope. A number of drugs have been investigated for their local effect after IA administration. A number of novel drug delivery systems are available for their own merits and demerits. This review discusses the pathophysiology of OA and formulation consideration of IA injections along with details of current and novel drug formulation for OA treatments.

  The present investigation deals with the preparation and evaluation of sustained release system of Salbutamol sulphate for the treatment of Asthama. The liposomes of Salbutamol sulphate were prepared using physical dispersion method by using soyalecithin and cholesterol. The ratio of soyalecithin and cholesterol was found to be important factors for achieving sustained release pattern. Factors studied influenced the lag time and in-vitro drug release of formulations. Dissolution studies of liposomes in phosphate buffer with pH 7.4 shows the drug release in colon could be modulated by optimizing the concentration of soyalecithin and cholesterol (6:1). The results of in-vitro dissolution studies indicated that formulation F1 is the most successful formulation of the study and exhibited drug release 96.24% in 12 h and the total release pattern was very close to the theoretical release profile of sustained release system. The study showed that the optimised batch F1 fulfills the requirement of good liposomal formulation. Stability study of the optimized formulation indicates no significant difference in release profile after a period of two month. Key words: Sustained release system, Soya lecithin: Cholesterol, Salbutamol sulphate, Liposomes

  Colloidal Drug Delivery system is an advancing technology expected to bring revolutionary changes in the field of pharma and health sciences including drug delivery, diagnostics and treatment. The advancement in colloidal drug delivery systems helps in preparing newer formulations which become useful for treatment of tuberculosis. Development of Metered dose inhaler (MDT) and Directly Observed Therapy (DOTS) also proves to helpful in treatment of tuberculosis. Various colloidal drug delivery systems liposomes, niosomes, nanoparticles and microparticles proves to be a successful tool for tuberculosis treatment. One of the preparations like microemulsions results in theimprovement of bioavailability of the drugs. Similarly corticosteroids also found to be an interesting tool here because corticosteroids reduced the risk of pleural thickening in tuberculosis patients. These various colloidal drug delivery systems minimize the problems of conventional therapy like poor penetration, drug resistance, systemic toxicity and also main the improved drug delivery. This article describes the applications of various formulations along with their future aspects in treatment of tuberculosis.