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Background Emulsions form the basis of a wide range of manufactured products in the pharmaceutical domain. They are constituted by at least two non-miscible liquids. However, instability is the major inconvenience of these galenic forms. Purpose Paraffin oil and gum arabic are used in the formulation of the oil-in-water emulsion type, which has a lot of applications in drug delivery, either as a medicament or as a vehicle. In the hospital pharmacy, the emulsion for intravenous administration, for example, must be the oil-in-water type. However, a good stability is required. The aim of the present study is the formulation of emulsion based on paraffin oil and to evaluate the influence of gum arabic content and mixing rate on the stability of emulsions. Material and methods Distilled water was used as a dispersant phase (75%) and paraffin oil as a dispersed phase (20%). Tween 80 and Span 80 served as mix surfactants (60/40). The formulation was performed according to the Lipophilic Balance-Hydrophilic (HLB) method. Gum arabic concentrations ranging from 2.5%–10% w/w were used. The stability of the emulsions was evaluated by centrifugation at 4000 rpm for 15 min. The creamer index (IC) was used for the interpretation of the results. The emulsions thus prepared are mixed at 4000, 8000 and16000 rpm for 10 min. Results The IC of emulsions ranged from 29%–30% with a HLB of 10.72. High levels of gum arabic (10, 7.5 and 5% (w/w)) increased the creaming, therefore the stability was decreased. After addition of 2.5% (w/w) of gum arabic, 1.6% creaming was observed. In 3% (w/w) gum arabic-containing emulsion, no creaming was observed. Microscopic images of emulsions mixed at 4000, 8000 and 16000 rpm, showed that emulsion prepared at 16000 rpm had homogeneously distributed individual small droplets with no sign of flocculation compared to the others. Conclusion The present experiment has shown that a concentration of 3% w/w gum arabic, and a mixing rate of 16000 rpm provided the optimum stability of oil-paraffin emulsion. Reference and/or acknowledgements Ramin L, et al. Soy protein isolate and gum arabic composite affects stability of beverage emulsion. Iran J Chem Eng 2009;6. No conflict of interest. |
