RESEARCH ARTICLE e-issn:

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1 Available online at International Journal of Trends in Pharmacy and Life Sciences Vol. 1, Issue: 5, 2015: PREPARATION AND EVALUATION OF LIPOSOMES CONTAINING ZIDOVUDINE CH.B.V.V.L.S.Latha,KVR. Raju & Y.Raja Jayarao KJR College of Pharmacy, Burugupudi. Rajahmundry, Andhra Pradesh E.Mail: ABSTRACT Liposomes, which are biodegradable and essentially non-toxic vehicles, can encapsulate both hydrophilic and hydrophobic materials, and are utilized as drug carriers in drug delivery systems. Stealth liposomes are surface modified liposomes in which PEG units are attached to the outer surface of liposome units, so that they can escape the opsonization effect in the blood, which is a major cause for decreased drug availability at its site of action. Pegylated liposomes are long- circulating with improved bioavailability and sustained action of loaded drug molecules. The aim of this study was to formulate and evaluate Stealth liposomal drug delivery system of Zidovudine antiretroviral drug, the first one approved for treatment of HIV. Zidovudines Stealth Liposomes are prepared by lipid hydration technique using rotary flash evaporator. The prepared liposomes were characterized by optical microscopy, scanning electron microscopic method respectively. Key Words: Stealth Liposomes, Pegylation, lipid hydration technique, Zidovudine *Corresponding Author: Ms. CH.B.V.V.L.S.Latha, KJR College of Pharmacy, Burugupudi. Rajahmundry, Andhra Pradesh E.Mail: bvvlslatha@gmail.com Received: 2911/2015 Revised: 18/11/2015 Accepted: 30/11/2015 INTRODUCTION During last two decades, considerable attention has been given to the development of novel drug delivery system (NDDS) [1]. Rational research in drug delivery began in 1950 s with the advent of polyclonal antitumor antibodies developed for tumour targeting of cytotoxic drugs to experimental tumors. Liposomes were discovered in the early 1960 s by British haematologist Dr Alec D Bangham (published 1965) and subsequently became the most extensively explored drug delivery system. The name liposome is derived from two Greek words: Lipos meaning fat and Soma meaning body [2-5]. Liposomes are spherical microscopic vesicles composed of one or more concentric lipid bilayers, separated by water or aqueous buffer compartments with a diameter ranging from 25 nm to nm. These are popular in terms of biocompatibility, biodegradability, low toxicity, and can control bio distribution of drug by altering the size, composition of lipids, and hence the characteristics [6]. These are the carriers that are suitable for encapsulation of drugs with different lipophilicities, such as strongly lipophilic drugs, strongly hydrophilic drugs, and drugs with intermediate log P. Liposomes can protect the encapsulated drug or drugs and can target the organ or tissue passively. But it was found that conventional liposomes suffer with 2 major drawbacks as sustained as well as targeted release system for drugs in vivo. First one is its attraction toward Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);

2 reticuloendothelial system (RES), which will cause the removal of drug from blood stream as well as result in adverse effects on the host defence system and will decrease the availability of entrapped drug to the other tissues. The next is recognition of conventional liposomes by RES leads to nonlinear pharmacokinetics for the carrier, which makes calculating the amount of entrapped drug required to attain therapeutic drug dose difficult. In addition, conventional liposome formulations containing saturated phospholipids and cholesterol are more prone to the influence of plasma proteins and other biologic fluids in vivo, which leads to rapid removal of drug contents. To avoid the above-mentioned difficulties, especially to avoid the RES uptake of the vesicles it is necessary to have previous administration of empty liposomes. Moreover, small uni lamellar vesicles have the drawback of low aqueous entrapment volume; the use of charged liposomes could be toxic. Thus, mechanical or electrostatic stabilization cannot improve the long circulation of liposomes in biologic systems. Further attempts to alter the bio distribution of liposomes resulted in the generation of new liposomal formulations called as stealth liposomes (SLs), which have considerably reduced RES uptake, and remain in circulation for long period of time, with dose-independent pharmacokinetics and have reduced susceptibility to protein-induced leakage. They are commonly composed of one or more amphiphilic phospholipids bilayer membranes (and thus also called as phospholipid vesicles) that can entrap both hydrophilic and hydrophobic drugs. A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drug or genetic material into a cell. Stealth liposomes are surface modified liposomes in which PEG units are attached to the outer surface of liposome units, so that they can escape the opsonisation effect in the blood, which is a major cause for decreased drug availability at its site of action. Pegylated liposomes are long- circulating with improved bioavailability and sustained action of loaded drug molecules [7]. Zidovudine or azidothymidine (AZT) (also called ZDV) is an antiretroviral drug, the first one approved for treatment of HIV. It is an analog of thymidine. Jerome Horwitz first synthesized AZT in 1964, under a US National Institutes of Health (NIH) grant. It was originally intended to treat cancer, but failed to show efficacy and had an unacceptably high side effect profile. Three scientists in the National Cancer Institute (NCI) and several other scientists in Burroughs Welcome Co., showed that this drug was an effective agent against HIV in vitro [8]. The team conducted the initial clinical trial that provided evidence that it could increase CD4 counts in AIDS patients. The Food and Drug Administration (FDA) approved the drug for use against HIV, AIDS and AIDS Related complex (ARC) on March 20, 1987 and then as a preventive treatment in MATERIALS AND METHODS Materials: Zidovudine was obtained from Dabur Indian limited Mumbai, Phosphatidyl choline, Poly ethylene glycol 4000 were purchesed from Sigma chemicals, Mumbai, The materials used in the present investigation were either AR/LR grade or the best possible pharma grade. Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);

3 Preparation of Stealth Liposomes These liposomes were prepared by lipid film hydration technique. In this method accurately weighed quantity of cholesterol and egg phosphatidyl choline were dissolved in minimum quantity of chloroform: methanol (1:1, 5ml v/v) taken in a round bottom flask. The flask was rotated at 100rpm at 200C for about 1.5cm above the water bath under reduced pressure (10-15mm Hg) until all the organic phase evaporated and a slimy layer was deposited on the wall of a round bottom flask. Zidovudine, polyethylene glycol 4000, and Brij 35 were added and dissolved in 10ml of distilled water was added to the film with gentle agitation, until a good dispersion of the mixture was obtained. The suspension was then sonicated to form unilamellar liposomes. The formulation used to prepare conventional and stealth liposome were shown in table. Table 1: Composition of Formulations Code Amount of Zidovudine Cholesterol Amount of phosphatidyl choline PEG 4000 Brij35 D:C:L Ratio F1 10 mg 15 mg 40 mg 7 mg 0.5 mg 1:1.5:4 F2 10 mg 15 mg 45mg 7 mg 0.5 mg 1:1.5:4.5 F3 10 mg 15 mg 50 mg 7 mg 0.5 mg 1:1.5:5 F4 10 mg 15 mg 55 mg 7 mg 0.5 mg 1:1.5:5.5 F5 10 mg 15 mg 60 mg 7 mg 0.5 mg 1:1.5:6 RESULTS AND DISCUSSION Optical Microscopy: The formulated conventional liposomes and stealth liposomes were observed using optical Microscope and photograph was taken. For conventional liposomes F2 and stealth liposomes F3. From the formulation we found vesicles and no cluster in the formulation and also no overlap of vesicles. Determination of percentage entrapment: Table 2: Determination of % Drug Entrapment Type of Formulations % Drug Entrapment F % F % F % F % F % Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);

4 % DRUG RELEASE % DRUG RELEASE RESEARCH ARTICLE e-issn: In vitro release studies: Table 3: In vitro Release Of Free Zidovudine Time in Minutes Absorbance at 254 nm Concentration μg/ml Amount of drug released mg % Amount of drug released INVITRO RELEASE OF FREE Zidovudine TIME IN MIN FREE DRUG Fig. 1: In vitro release of free Zidovudine INVITRO DRUG RELEASE OF CONVENTIONAL LIPOSOMES - F TIME IN MIN Fig. 2: In vitro release of conventional liposomes-f3 Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);

5 Table 4: In vitro release conventional liposomes F3 Time in Minutes Absorbance at 254 nm Concentration μg/ml Amount of drug released mg % Amount of drug released STABILITY STUDIES OF CONVENTIONAL AND STEALTH LIPOSOMES Temperature Table 5: Stability Studies Of Conventional And Stealth Liposomes Amount of drug retained (%) after months Initial I II III Refrigeration 4 o C±1 o C Room temperature o C±2 o C RH-70%±5% CONCLUSION An effort was made to formulate the Zidovudine Stealth Liposomes. In this study, both Conventional and Stealth liposomes were formulated and evaluated to explore the advantages of Stealth liposomes over Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);

6 Conventional liposomes. Both the formulations were evaluated in vitro. Stealth liposomes got higher entrapment efficiency and shows prolonged drug release in vitro studies due to the presence of PEG From the results the present experiment may be concluded that F-3 has no cluster in the formulation and also no overlap of vesicles, very small in size and slow release and stable. REFERENCES 1). Santhi K, Dhanraj SA, Nagasamy VD, Sangeetha S, Suresh B. Preparation and optimization of sodium alginate nanospheres of methotrexate. Indian J. Pharm. Sci. 2005: 67; ). Dua JS, Rana AC, Bhandari AK. Liposomes Methods Of Preparation and Applications. International Journal of Pharmaceutical studies and Research. 2012:2(1); ). Brahmankar DM, Sunil BJ. Biopharmaceutics and Pharmacokinetics A Treatise, Vallabh Prakashan pp ). Anwekar et al. Liposome as Drug Carriers. International Journal of Pharmacy & Life Sciences.2011: 2(7); ). Akbarzadeh et al. Liposome: Classification, Preparation and Applications. Nanoscale research letters A Springer Open Journal. 2013:8; ). Tamizharasi S, Rathi JC, Rathi V. Formulation, characterization and in vitro release kinetics of aceclofenac loaded poly (caprolactone) microspheres. Indian Drugs. 2007: 44; ). Julie AC, Amanda W, Samir M. Role of particle size in phagocytosis of polymeric microspheres. Pharm Res. 2008: 25; ). Arun K, Roger B, Guru B. Effect of liposome composition and cholesterol on the cellular uptake of stavudine by human monocyte/macrophages. Cell Mol Biol Lett. 2000; 5; Latha CHBVVLS et al. Int J Trends in Pharm & Life Sci. 2015: 1(5);