Nanoliposomes to the long-range mutual repulsion between adjacent bilayers.

Nanoliposomes have ability to approachmerely the precise cells, which is a prime requisite to accomplish preferreddrug concentration at the target position so that the adverse effects can beminimized and optimum therapeutic efficacy on healthy cells and tissues can beachieved. They can also to protect the active moiety in systemic circulationand deliver it to the desired site of action at a sustained rate 14. Thus,nanoliposomes as a carrier helped in improving the therapeutic index of drugsby selective and controlled drugdelivery, by decliningthe exposure of toxic drugs to sensitive tissue, and by controlling the drugpharmacokinetics and biodistribution.

All categories of drugs like hydrophobic,amphipathic and hydrophilic drugs are suitably delivered by using nanoliposomesas a carrier as it carried both lipophilic and hydrophilic environment in onesystem (27-29). Moreover, nanoliposomes have found imminent applications in thevarious fields of nanotechnology like gene delivery, cancer therapy, agriculture,food technology, diagnosis, and cosmetics. High production cost, oxidation andhydrolysis of phospholipids, seepage and blending of encapsulateddrug/molecules, less stability, small half-life, and squat solubility are someof the limitations of nanoliposomes. However, the stability problem ofnanoliposomes in vitro and in vivo limits their application. The nanoliposomeshave tendency to aggregate or degrade and fuse, which causes leakage of corematerial during storage and clears rapidly from the system after intravenousinjection. Literature suggested that, among various factors that affect thestability of nanoliposomes, carrier’s surface characteristics like charge,lipophilicity, and fluidity, are of great importance. Therefore, the littlemodification of carrier’s surface by using polymers with desired properties, wecan easily modulate there in vitroand in vivo stability.Polymer coating is a pledging wayof amending the surface characteristics of nanoliposomes, in which thenanoliposomes suspension was mixed with a polymer solution simply without anychemical linking of polymers to the lipid molecules.

Polymer coating improvedthe stability of nanoliposomes during storage due to the long-range mutualrepulsion between adjacent bilayers. Various natural polymers like polysaccharidesand synthetic polymers like polyethylene, polyvinyl alcohol, or polyacrylamidehave been used to modify the surface characterstics and to increase thestability of nanoliposomes.  Among whichchitosan is a positively charged polysaccharide and can be used to increase andmodify the characteristics of nanoformulations, is found to have a promisingfuture in the medical and pharmaceutical fields. Chitosan, a polycationic polymer dueto existence of amino groups comprised mainly of glucosamine units. It isN-deacetylated derivative of chitin having antioxidant and anti-in?ammatoryproperties Qiaoet al., 2011, Cao et al., 2016.

Tissue engineering, obesity control and drug development are its several promisingapplications. During new drug formulation it used most widely as being biocompatibleand biodegradable it also provide a protective capsule like shield to drugmolecule Mady andDarwish, 2010. Its chemicalconfiguration and various suitable features like abundance, hydrophobicity,antimicrobial activity, low toxicity, biocompatibility, and biodegradability madechitosan an important ingredient to be used in the preparation various modifiedformulation and carriers like microsphere, microfilme, nanoparticles, films,gels. As a carrier to entrapped and release active ingredient, it foundapplications in various fields like cosmetics, pharmaceuticals, food andbiotechnology. Literature suggested that various authors have used chitosan or relatedpolymers as a coating material for liposomes, nanoliposomes for targetingpurposes and to increase their stability towards drug release Dong and Rogers, 1991. We recognized that suitablecombination of the polymer based and lipid-based systems could amalgamate theadvantages and diminish the disadvantages of each system, and thus lead to developmentof new system carrying advantages of both systems Dai et al.

, 2006.In the present work,nanoliposomes were prepared by using reverse-phase evaporation (REV) method andmodified emulsification and ultrasonication (MEU) method and then, both thepreparations were coated with different concentrations of chitosan solutions.Then, the effects of different concentration of chitosan solution on particlesize, zeta potential and in vitro drug release rate were studied. The transmissionelectron microscopy, FTIR studes, DSC analysis, particle size and zetapotential studies were used to investigate presence of chitosan coating onnanoliposomes. The characteristics of uncoated and chitosan-coatednanoliposomes were studied to develop and further optimize nanoliposomes thatare directed for their systemic pharmacological applications.

Nanoliposomes were prepared by reverse-phaseevaporation (REV) method and modified emulsification and ultrasonication (MEU) method.In reverse-phase evaporation method, soya lecthin and cholestrol were dissolvedin diethyl ether and gefitinib was dissolved in distilled water. The mixing oforganic phase and aqueous phase was done in ratio (3:1, v/v), and a lipid filmwas formed under reduced pressure at 40 ?C, using a rotary evaporator. Then 10ml phosphate buffer solution (0.10 M, pH 7.

0, PBS) containing Tween 80 was addedunder a stream of nitrogen. Nanoliposomes were obtained by reducing the size ofnanoliposomes using ultrasonication with a probe sonicator in an ice bath with1s ON, 1s OFF intervals, for a total period of 10 min Ding et al., 2011. In modified emulsification and ultrasonicationmethod, gefitinib was dissolved in anhydrous ethanol to obtain a desiredconcentration of gefitinib ethanolic solution. The ethanolic solution ofgefitinib containing lipid phase was heated on a water bath at 60 ?C.

Tween 80was dissolved in 10ml of phosphate buffer of pH 6.8 and maintained at 60 ?C asthe aqueous phase. The aqueous phase was dropped into the non-aqueous phaseunder magnetic stirring. The consequential preparation was stirred for another10 min, and then ultrasonication was done. Then, the preparation placed on anice bath and diluted to a desired volume.

Finally the preparation was filteredthrough a 0.22µm membrane filter Guan et al., 2011. Both the preparations werecentrifuged seperately. The formed pellet was washed with sterile doubledistilled deionised water and re-centrifuged; this step was repeated four timesand the pellet then re-suspended in an appropriate amount of sterile doubledistilled deionised water.For chitosan-coated nanoliposomes,an appropriate amount of percentage (w/v) chitosan solution was added drop wiseto the nanoliposomal suspension under magnetic stirring at room temperature.After addition of chitosan, the mixture was left to stir for approximately 1 hand then incubated overnight at 4 ?C Mady and Darwish, 2010, Shin et al.,2013.