International Journal of Chemistry and Pharmaceutical Sciences. International Journal of Chemistry and Pharmaceutical Sciences

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1 International Journal of Chemistry and Pharmaceutical Sciences Journal Home Page: Research Article Open Access Emulsification of Neem oil: effect of polar solvents and chain length of surfactant Manisha Bhattacharya*, S.G. Dixit RJ College, Ghatkopar, Mumbai, UICT, Matunga, Mumbai, India A B S T R A C T Neem oil was emulsified by using surfactant mixture oleic acid and Tween 20,40, 60, 80, etc. The dispersion medium used for these emulsions were distilled water, water-ethylene glycol, water-formaide, water-glycerol. Compositions of these binary mixtures were varied by changing the percentage of solvents. Emulsions were studied at different concentrations of surfactants also. It was observed that surfactants concentration and chain length of surfactant, concentration of oil composition of dispersion medium play an important role in emulsion stability. Keywords: Neem oil, Formamide, Ethylenee glycol, Glycerol, Tween series A R T I C L E I N F O CONTENTS 1. Introduction Materials and Methods Results and Discussion Conclusion Acknowledgement References Article History: Received 27 October 2015, Accepted 30 November 2015, Available Online 27 December 2015 *Corresponding Author Manisha Bhattacharya RJ College, Ghatkopar, Mumbai, UICT, Matunga, Mumbai, India. Manuscript ID: IJCPS2748 PAPER-QR CODE Citation: Manisha Bhattacharya. Emulsification of Neem oil: effect of polar solvents and chain length of surfactant. Int. J. Chem, Pharm, Sci., 2015, 3(12): Copyright 2015 Manisha Bhattacharya. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. 1. Introduction An emulsion is a dispersed system containing ning at least two immiscible liquid phases. The dispersed droplets strive to come together in order to minimise this effect a third components, the emulsifying agent is added d to the system to improve its stability. Emulsifying agents are frequently used in combination to get better emulsion. This mixture of emulsifiers 1) helps to obtain desired. d. Hydrophiliclipophilic balance in the emulsifier, 2) enhance stability and International Journal of Chemistry and Pharmaceutical Sciences cohesiveness of the interfacial film, 3) has an impact on consistency and feel of the product. Neem oil is a mixture of three chemical components - Biglycerides, bitters and odoriferous constituents. Chemical composition of neem oil shows presence of Palmitic acid, Stearic acid, Linolic acid, Arachidic acid in smaller amounts as compared to oleic acid which is present to the extent of 82%. [1,2] Therefore in the present investigation oleic acid was used as sodium 2175

2 oleate which can be prepared in situ to get stable spontaneous emulsion. Besides Neem oil is also used for illumination soap making, medicinal purposes. Polyoxyethylene sorbitan fatty acid esters (polysorbate or Tween) are used as emulsifier in many domestic, scientific and industrial applications. They are non toxic, hydrophilic, non-ionic surfactants and hence find widespread applications in pharmaceutical emulsion preparation. For a variety of essential oils and oil soluble vitamins they are used as solubilizing agents. [3-5] Non-aqueous aprotic solvents like. Ethylene glycol( EG), Glycerol (GLY), Formamide (FA) are often used in combination with surfactants in pharmaceutical products, cosmetics and pesticidal formulations, therefore study of effect of these solvents on physical properties of surfactant solution is highly desirable. Ethylene glycol and glycerol are biological solvents.eg, GLY, FA favour aggregation of surfactant molecules leading to micellization. In the present study emulsification, of neem oil using oleic acid and Tween series were studied in various dispersion media like water, water-ethylene glycol, water-glycerol, water + formamide. 2. Materials and Methods Materials: The non-ionic surfactants Tween20 (polyoxy ethylene sorbitan monolaurate), Tween-40(polyoxy ethylene sorbitan monopalmitate), Tween60 (polyoxy ethylene sorbitan monostearate), Tween80 (polyoxy ethylene sorbitan monooleate), Oleic acid 98% pure were procured from Sisco Research Laboratories. Solvents Ethylene glycol, glycerol, formamide were purchased from SD Fine chemicals. They were AR grade. Water used was deionised & doubly distilled. Neem (Azardirachtin indica oil, was purchased from Ashwin Pharma. Formulation of emulsion: Accurately weighed surfactant mixture was dispersed in oil phase in a continuously working valve homogenizer. The homogenizer used was Universal Motors Homogenizer India which has a more speed of 6000 rpm. The emulsifiable concentrate formed thus was then mixed with water and stirred using homogenizer (speed 3000 rpm) for 8-9 minute. resulting in the formation of emulsion. The emulsion were poured in graduated glass cylinders and kept at constant temperature. Separation of oil, cream phase were determined visually for judging stability of emulsion. Emulsions with neither phase separation, coalescence, flocculation even after 24 hrs were considered as stable emulsion. [10,11] unsaturation plays a role in emulsifying ability of surfactant. As the number of carbon atoms increase in alkyl chain length of surfactant, hydrophobicity character of surfactant increases which strengthens hydrophobic interactions & in turn enhances emulsifying ability of surfactant. Stability of oil/water interface is enhanced with the increase in length of alkyl chain. Formation of emulsion becomes easier at lower interfacial energy, though it is not the only factor which plays role in emulsion stability [12]. From Table 1 it is seen that emulsion formed by Tween 20 shows least stability which has least number of carbon atoms in its alkyl chain length. Whereas Tween 80 emulsion shows maximum stability. Though Tween 60 & Tween 80 has same number of C atoms in their alkyl chain length. Stability of emulsions formed by Tween 80 is maximum due to unsaturation in alkyl chain which enhances hydrophobic character of it. Effect of surfactant concentration: Stability of emulsion is also affected by adsorption of surfactant molecules at interface & the film formed by it. Development of strong interfacial film prevent coalescence of emulsion. Maximum adsorption of surfactant molecules at oil / water interface develops a strong interfacial film which is achieved by higher bulk concentration and longer alkyl chain of surfactants. This trend is observed for some of the emulsion as shown in table 2. Many studies have shown that surfactant concentration play an important role in emulsion stability. [13] At very low concentration of surfactant due to agglomeration stable emulsion is not obtained and at very high concentration emulsion is destabilized due to rapid coalescence. Effect of solvent: Stability of emulsion is greatly affected by the presence of polar solvent. [14-16] 3. Results and Discussion Stability of emulsion is affected by various parameters such as concentration surfactants, chainlength of surfactant used as emulsifier, solvents used in dispersation medium, ph of dispersion medium. Effect of chain length of surfactant: In the present study Tween 20 (C -12), Tween 40 (C -16), Tween 60 (C -18) & Tween 80 (C-18) are used. Though Tween 60 & Tween 80 has same number of carbon atoms, the presence of International Journal of Chemistry and Pharmaceutical Sciences 2176

3 Polar solvents like EG, GLY, FA at various percentage are used along with water. These solvents are Hydrogen bond donar solvents. They form intermolecular Hydrogen bond with poly oxyethylene chain of surfactants. Glycerol has very high concentration of OH groups per unit volume than Ethylene glycol. Hence Glycerol shows stronger Hydrogen bond interactions with surfactant molecules, hence does not give stable emulsions. Presence of Ethylene glycol also reduces the stability of emulsions to some extent in comparison with the emulsions formed in water alone. The presense of the OH group as part of the structure of the solvent play important role in emulsification. In formamide there is not a single OH group but presence of -NH 2 group forms a potential Hydrogen bonding centre which plays important role in the sta does not give bility of emulsion. But among three Hydrogen bond donar solvents formamide shows better stability. An intermediate behaviour is shown by Ethylene glycol but Glycerol does give stable emulsion.the presence of these nonaqueous polar solvents affects stability of emulsions. The emulsions formed in pure water are more stable than the emulsions formed in aqueous solutions of these solvents. Table1: Effect of various surfactants (Tween series) on percentage stability of emulsion % of Neem oil Surfactants Tween20 Tween40 Tween 60 Tween80 Pure Water %Formamide %Formamide %Formamide % Ethylene glycol % Ethylene glycol % Ethylene glycol International Journal of Chemistry and Pharmaceutical Sciences 2177

4 %Glycerol %Glycerol %Glycerol Table 2: Effect of concentration of surfactants on percentage stability of emulsion % of Percentage of Tween 20 Neem oil 3% 5% 7% 10% Pure Water %Formamide %Formamide %Formamide % Ethylene glycol % Ethylene glycol % Ethylene glycol %Glycerol %Glycerol %Glycerol Conclusion As the number of carbon atoms increase in alkyl chain length of surfactant, hydrophobicity character of surfactant increases which strengthens hydrophobic interactions & in turn enhances emulsifying ability of surfactant.. The presence of unsaturation plays a role in emulsifying ability of surfactant. Surfactants with greater number of C atoms in their alkyl chain or unsaturation give more stable emulsion than surfactants having lesser number of C atoms. At very low concentration of surfactant due to agglomeration stable emulsion is not obtained and at very high concentration emulsion is destabilized due to rapid coalescence. Presence of polar solvents like EG,GLY,FA reduces the stability of emulsion when their aqueous solution is used as dispersion on medium Glycerol has higher concentration of hydroxyl group per unit volume and its aqueous solution does not give stable emulsions. Shows aqueous solution of ethylene glycol shows intermediate behaviour. Formamide, though not a single hydroxyl group is present in its structure. NH 2 group acts as potential hydrogen bonding centre. In International Journal of Chemistry and Pharmaceutical Sciences 2178

5 comparison with GLY+H 2 O, EG+H 2 O, FA+H 2 O, pure water shows better stability. 5. Acknowledgement: The Financial support by G.D.Gokhale trust is gratefully acknowledged. 6. References [1] Bringi, N.V.; Thakur (Ed Bring, N.V., Non traditional oil seeds & oils in India; [2] Hiditch, P., Murti, S; Fatty acids and glycerides of Neem (margosa) oil J. Soc. Chem Ind ; 310, [3] Mohajeri E ; Noudeh GD ; Effect of temperature changes on critical micelle concentration for Tween series surfactant E-journal of Chemistry ; 2012, 4, [4] Cirin D M ; Posa M M ; Krstonosic V s ; Milanovic M L ; Conductometric study of sodium dodecyl sulphate nonionic surfactant (Triton x - 100,Tween20, Tween60, Tween80, Tween85) mixed micelles in aqueous solution,hem. Ind. ; 2012, 66(1), [5] Gui li Y ; Chen B ; Chen Z ; Zhu L ; Surfactant effects on the affinity of plant cuticles with organic pollutants J. Agric. Food Chem ; 2009, 57, [6] Lu D ; Rhodes D G ; Mixed composition films of spans and Tween 80 at the air water interface, Langmuir ; 2000, 168, [7] Chakraborty S ; Shukla D ; Jain A ; Mishra B ; Singh S ; Assessment of solubilization characteristics of different surfactants for carvedilol phosphate as function of P H J. of Colloid & Interface Sci. 2009, 325, [8] Gibbson, RE; Loeffler, O.H. ; Pressure-Volume- Temperature relation in solutions.v. The energyvolume coefficients of carbon Tetrachloride, water and ethylene glycol; J. Amer Chem Soc., 1941, 63, 898. [9] Dock, M.R.; J. The importance of solvent internal pressure and cohesion to solution phenomena ; ChemSoc Rev, 1975, 4, 211. [10] L, Rydbag, Wilton, I ; The Function of phospholipids of soyabean Lecithin in emulsions J. Am Oil Chem Soc. 1981, 58, 830. [11]. D. A. Yeadon, L.A. Goldblatt, A. M. Attachul, Lecithin in oil in water emulsion J. Am. Oil Chem soc, 1958, 35,435. [12] Ivan B. Ivanov, Peter A. K.; Stability of emulsion under equilibrium and dynamic condition, ; Colloid Surf,; A, 1997, 128 (1-3), 155. [13] G.Ostberg,B. Bergenstahl, M Huldden,Colloid and Surfaces. A, Physicochemical and Engineering Aspects 94(2-3) (1995) [14] Fletcher,P.D.I;Galal M; Robinson,B.H. J.Chem. soc. Faraday Trans Structural study of aerosol- OT..stabilised microemulsions of Glycerol dispersed in n-heptane. 1984, 80,3307 [15] Schubert,K,V,; Lusvardi,, K.M.; Kaler, E.W. Polymerization in nonaqueous microemulsions Colloid polym Sci. 1996, 274, 875 [16] Fletcher,P.D.I;Freedman R,B,; Robinson, B.H., Rees G.D. Schomacker R. Lipase catalysed ester synthesis in oil continuous microemulsions Biochim Biophys Acta. 1987, 912, 278. International Journal of Chemistry and Pharmaceutical Sciences 2179