The Partitioning Effect of the Preservatives in Emulsion - Lab Report Example

?Experiment HLB requirement: Paraffin oil in water is emulsion can be done by using the most common emulsifying agent Sodium lauryl sulfate and Span 80. When SDS is used, then anionic detergent will increase the hydrophilic nature of the emulsion. The water in oil (w/o) emulsion has the HLB value well with in the detergent limit. The emulsion is prevented from breaking by reducing the surface tension of the film. By the combination of two emulsifiers with big difference in HLB values, the film is strengthened. Introduction: Emulsion is a system of two components that are immiscible with each other. They are usually liquids of which one is dispersed on another. There are two major classes of emulsions: oil in water (o/w) and water in oil (w/o). These emulsions are stabilized by an emulsifier, which reduces the surface tension between the two phases and helps to maintain the emulsion from breaking. Surfactants or detergents are the most common emulsifiers. The HLB value for the surfactants ranges from 13-16. Emulsifiers have both hydrophobic and hydrophilic properties and they are provided by the emulsifying agents. The combination of the surfactants gives us more rigid films and reduces the interfacial surface tension. The Hydrophile – Lipophile balance (HLB) is used to identify the combination effect of the emulsifying agents. The HLB of each formulation is calculated by the formula: HLB [formula] = f. [OSC]. HLB[OSC]. + (1-f) [WSC]. HLB [WSC]. In our present study the effect of mixing two emulsifying agents that have a wide difference in the HLBs were determined. Sodium lauryl sulfate and Span 80 are used in this experiment. Experiment: Determination of HLB requirement of the oil: Table 1 Emulsion Liquid paraffin + 2% Span 80 Liquid paraffin Water + 2% SDS Water HLB E1 1.3 ml 8.7 ml 8.7 ml 1.3 ml 13.609 Discussion: The HLB value of our emulsion is 13.609. This value comes under the detergents category. As the HLB value is high, it is more hydrophilic. SDS acts as the wetting agent by enhancing the spread of the water over the surfaces. By adding SDS to the emulsion, the breaking of the paraffin emulsion can be stabilized well. The w/o emulsion can be maintained very well, if we use 13% Span 80 and 87% SDS. The HLB value falls well with in the range of detergents and thus our paraffin oil Emulsion can be stabilized very well for a long time. Conclusion: The combination of Sodium lauryl sulfate (the more anionic compound) and Span 80 (the non-ionic surfactant) at the ratio of 87%: 13 % has reduced the surface tension of the paraffin oil emulsion and is made more water soluble. The HLB value of the emulsifiers (13.6) falls into the category of detergents and thus proves to be a good emulsion. Experiment 2: the partitioning effect of the preservatives in Emulsion: Abstract: The partitioning effect of the three preservatives benzoic acid, methyl parabens and propyl parabens were determined based on their absorbance values at three different nanometers 230 nm, 257 nm and 255 nm respectively. It was found that propyl paraben gave the maximum absorbance at 230 nm. This indicates that propyl paraben can be used as the best preservative agent for the paraffin in water emulsion to prevent the anti microbial activity. Introduction: Parabens are the stable, non-volatile and more common anti bactericidal and anti fungal agents. They are widely used in the food, cosmetic and pharmaceutical industry. (Bean, 1972). They are non-toxic and they never accumulate on the body. They have no toxic effect on oral and parentral routes of administration. (Soni et al, 2001). Most common parabens are methyl parabens and propyl parabens. Benzoic acid is the best fungi static agent against the species Aspergillus. Benzoic acid is also found to have a good dimerization effect in the paraffin in oil emulsion in pharmaceutical industry. (Anderson and Chow, 1967). The addition of benzoic acid is found by the decrease in the aqueous phase concentration. Glycerin or propylene glycol is commonly used in the pharmaceutical or cosmetic emulsions in order to increase the preservative solubility in the aqueous phase by reducing the partition coefficient. As a result, the preservatives are available at the top of the emulsions. This enables the preservatives to have greater effect on the bactericidal activity. 5 to 10% propylene glycol is used in the food, pharmaceutical and cosmetic industry. Experiment: The three preservatives were added to the liquid paraffin in water at different concentrations. The mixture was mixed well and kept for 15 minutes. The absorbances of the solutions were measured at different nanometers. The results are tabulated in the column. Result: The absorbance values of the three preservatives: Table 2 Component (%) E1 E1P E2 E2P E3 E3P Liquid Paraffin 10 ml 10 ml 10 ml 10 ml 10 ml 10 ml Propylene Glycol 1 ml 1 ml 1 ml Benzoic Acid 0.02 ml 0.02 ml Methyl Parabens 0.004 ml 0.004 ml Propyl parabens 0.02 ml 0.02 ml Water to 20 ml 20 ml 20 ml 20 ml 20 ml 20 ml Absorbance at 230 nm 1.253 2.401 2.455 2.551 2.651 2.886 Absorbance at 257 nm 0.859 1.859 1.381 1.561 2.619 1.619 Absorbance at 255 nm 0.833 1.205 1.333 1.861 2.618 2.750 Discussion: The emulsions containing benzoic acid, methyl parabens and ethyl parabens found to have a greater absorbance at 230nm. The maximum absorbance value for methyl paraben is 257 nm and for propyl paraben is 255 nm but the maximum absorbance results were observed for 230 nm. The change in the absorbance values may be due to the addition of other components such as liquid paraffin, propylene glycol. The maximum absorbance is the optical range in which the given component absorbs more light. This value is unique for the components. In our experiment, the maximum absorbance was found to be 230 nm for the three preservatives. This may be due to the experimental errors or human errors. Conclusion: Benzoic acid and its derivatives are the most common preservatives with good antimicrobial activity. At 230 nm, the propyl parabens has given the maximum abosrobance value. Though the results have some controversy with the maximum absorbance values, this can be considered as the best preservative. The main justification for this conclusion is that it is a derivative of benzoic acid. References: Bean, HS 1972, Preservatives for pharmaceuticals, Journal of the Society of Cosmetic Chemists, vol. 23, pp: 703- 720. Chow, CE, and Anderson, RA, 1957, The distribution and activity of Benzoic acid in some emulsified systems, Journal of the Society of Cosmetic Chemists, vol. 18 pp: 207-214. Soni, MG, Burdock, GA, Taylor, SL and Greenberg, NA 2001, Safety assessment of propyl paraben: a review of the published literature, Food and Chemical Toxicology, vol. 39, no. 6, pp : 513-32. Read More