بررسی ویژگی های کلوئیدی نانو لیپوزوم های حاوی بتاکاروتن تولید شده به روش حرارتی

ریزپوشانی مواد غذا دارو در حامل های لیپیدی، از جمله لیپوزوم ها، منجر به افزایش قابلیت زیست فراهمی مواد فعال، رهایش کنترل شده و دقیق آن ها، حفظ پایداری آن ها در برابر شرایط مختلف محیطی و حلالیت مواد فعال آبگریز در محیط آبی می شود. از جمله ترکیبات مغذی آبگریز با خاصیت آنتی اکسیدانی و پروویتامینی مفید، بتاکاروتن می باشد که خاصیت آب گریزی این ماده و نیز حساسیت بالا در شرایط مختلف محیطی کاربرد آن را برای غنی سازی مواد غذایی محدود کرده است. هدف از انجام این پژوهش تولید و بررسی نانولیپوزوم های حامل بتاکاروتن به روش گرمایی اصلاح یافته (مظفری اصلاح شده) و بررسی ویژگی های مهم کاربردی آن بود. اندازه ذرات نانولیپوزوم های حامل بتاکاروتن در غلظت های مختلف لستین، کوچک تر از 500 نانومتر به دست آمد و برای غلظت های بهینه لستین، 8464 نانومتر تعیین شد. استفاده از فیتواسترول (گامااوریزانول)، جهت حفظ پایداری غشای سیستم های لیپوزومی، موجب کاهش اندازه ذرات در غلظت های مختلف لستین گردید بطور مثال در غلظت 200 میلی‌گرم لستین اندازه ذرات از 88 نانومتر به 64 نانومتر کاهش یافت. همچنین گامااوریزانولِ مورد استفاده در لیپوزوم، روی کارایی ریزپوشانیِ بتاکاروتن موثر نبود و در هر دو سیستم کارایی حدود 89 درصد محاسبه شد. پایداری لیپوزوم های بدون گاما اوریزانول و حاوی آن، بر اساس پتانسیل زتا که معیاری برای دافعه الکترواستاتیک و پایداری است، مناسب بدست آمد.

The study of the colloidal properties of nano liposomes containing betacarotene produced by thermal method

Introduction : The encapsulation of nutraceuticals in lipid based carriers, such as liposomes, can lead to increasing of bioactive ingredients bioavailability and controlled release, maintaining their stability in different environmental conditions and increasing solubility of hydrophobic active ingredients in aqueous conditions. Food grade liposomes are being increasingly used in food industry to delivery hydrophilic and hydrophobic components such as vitamin E and vitamin C, ascorbic asid, nutraceuticals, essential omega 3 fatty medium chain fatty acidsvitamine C, nisine, cartenoides, oleic acids, polyphenols include catechine, synamic acids. One of the hydrophobic nutrients with antioxidant and beneficial provitamine property is betacarotene, which its high hydrophobicity and sensitivity in different environmental conditions has limited using of it for foodstuff enrichment. In order to improve the characteristics of the lipid bilayer, cholesterol traditionally has been included in the lipid membrane. It is important in decreasing permeability and strengthening the membrane. People suffering from hypercholesterolaemia are encouraged to avoid foods containing cholesterol. Since the plant sterols are natural compounds found in plant cell membranes which help maintain the membrane integrity. Such as Gama oryzanol is combination of different of plant sterols that is used in the formulation of nanoliposomes in this study to improve the stability of bilayers. The principal aim of this study was to prepare betacaroten encapsulated nano liposome formulations as a mean to improve its aqueous dispensability and to study the effect of lecithinphytosterol concentrations on the partical size, encapsulation efficiency (EE), zeta potential, turbibility of beta carotene loaded nanoliposomes to get the optimized formulation. Materials and methods: Preparing liposomes is being carried out using different methods one of which is a novel technique called is “Mozafari method” (based on heating method). This method is characterized by the absence of organic solvent for the solving of lipids.Nontoxicity of produced liposomes; rapid production and scalability are some of the advantages of Mozafari method over other methods of liposome production. In this study, the liposomal ingredients were added to a preheated (60 0C, 5 min) water, mixeture of betacarotene, gamma oryzanol solution and glycerol (final concentration 3% v/v) were added. The mixtures volume increased by adding warm water until 50ml, the mixture was further heated 60 while stirring 1200 rpm for 5060 min under nitrogen atmosphere. Results and discussion: Effect of different concentration of lecithin (20, 40, 75, 100, 150, 200 mg) on particle size and zeta potential of nanoliposomes with constant amount of beta carotene (4 mg) and gammaoryzanol for different concentration of lecithin with ratio 1:14 w/w were evaluated. The Particle size of nano liposomes with different concentration of lecithin was obtained below 500nm andthe optimal concentration of lecithin was 100 mg that particle size was minimum (6488 nm).The gammaoryzanol is a natural phytostrol which is as stabilizer for liposome membrance and promoting agent of hardness of vesicles wall however, the particle size of liposomes were reduced especially in low concentration of lecithin. The using phytosterols (gamma oryzanol) for maintaining the stability of liposomal membranesystems caused to reducing of particle size from 88nm to 64nm in 200 mg concentration of lecithin. The entrapment efficiency increased by increasing concentration of lecithin for nanoliposomes. It is because increasing the lecithin concentration, more vesicles were produced which in turn increased the loading capacity of nanoliposomes. In the liposome structure, the aqueous core and bilayer are the hydrophilic and hydrophobic parts, respectively. Therefore, the phospholipid bilayers place for beta carotene, and other hydrophobic substances. The entrapment efficiency in different concentration of lecithin was between 2798%. The entrapment efficiency of liposomes containing beta carotene that used gamma oryzanol was less than liposomes without gamma oryzanol probably because the position of capsulation of gamma oryzanol and beta carotene is same in the bilayer of liposome that’s hydrophobic source of liposomes. But Gamma oryzanol was not effective on encapsulation efficiency of betacarotene. The zeta potential, the electric potential in the interface or particle surface charge, is used to predict the stability of colloidal systems. In general, higher zeta potential values, regardless of their positive or negativity, indicate a higher and longerterm stability of the particles. Zeta potential of liposomes, which is a measure for the electrostatic repulsion and stability, was 29 and 35 milivolt for samples with and with not containing gamma oryzanol, respectively. For turbidity of liposomes, encapsulation of bioactive compounds can change the optical appearance due to the fact that the refractive index at the interface between solvent and internal phase changes and the size of liposomes may be altered. Increasing significantly of turbidity of liposomes (16% 80%), the wave length increase from 0.116 to 0.585 cm1 high concentration of lecithin maybe due to increasing visuals and hydrophobic interactions.