药剂学实验-Preparation of emulsion base 乳膏剂基质.doc

Pharmaceutics ExperimentPreparation of Emulsion BaseAbstractOintments are semi-solid preparations made of medicaments and suitable bases, which are intended for external application to the skin. In this experiment, W/O and O/W types of emulsion bases is prepared. The emulsion bases include water phase, oil phase and emulsifier. The general method of preparation is melting oil phase and dissolving water phase separately, then mix them completely at the temperature of 80, and stirring until the mixture cool to R.M.Key wordsointments, emulsion base, dosage formsIntroductionOintments are semi-solid preparations made of medicaments and suitable bases, which are intended for external application to the skin. Ointments bases recognized for use as vehicles distinguished into three general classes: the oleaginous, the emulsion bases, and the water-soluble bases.An ointment is intended for external application to the skin or mucous membranes. Ointments have a water number that defines the maximum amount of water that it can contain. They are used as emollients or for the application of active ingredients to the skin for protective, therapeutic, or prophylactic purposes and where a degree of occlusion is desired.Ointments are used topically on a variety of body surfaces. These include the skin and the mucous membranes of the eye (an eye ointment), chest, vulva, anus, and nose. An ointment may or may not be medicated.Ointments are usually very moisturizing, and good for dry skin. They have a low risk of sensitization due to having few ingredients beyond the base oil or fat, and low irritation risk. There is typically little variability between brands of generics and name brand drugs. They are often disliked by patients due to greasiness. 2The vehicle of an ointment is known as the ointment base. The choice of a base depends upon the clinical indication for the ointment. The different types of ointment bases are:Hydrocarbon bases include hard paraffin, soft paraffin, microcrystalline wax and ceresine. Absorption bases include wool fat, beeswax. Water soluble bases include macrogols 200, 300, 400. Emulsifying bases include emulsifying wax, cetrimideThe medicaments are dispersed in the base, and later they get divided after the drug penetration into the living cells of skin. The rate and extent of release of sorbic acid from 6 ointment bases were assessed. The amount of drug released depended on the composition of the base and the concentration of sorbic acid employed. The rate of release decreased in the following order: water soluble o/w emulsion oleaginous hydrophobic w/o emulsion base.3Methods1. Preparation of O/W emulsion baseMaterialDoseFunctionStearic acid4.8gOil phaseThe regent of ammonium stearateGlycerol monostearate1.4gLiquid paraffin2.4gVaseline0.4gWool fat2.0gTriethanolamine0.16gWater phaseDistilled waterAdd up to 40gAdd stearic acid, glycerol monostearate, liuid paraffin, Vaseline and wool fat into evaporating dish. The dish is heated to 80 in water bath until melting completely. Then dissolve triethanolamine in distilled water and heat it in 80 of water bath. Pour oil phase into water phase with stirring in 80 of water bath, then stirring it until it cool to R.M.The temperature of water phase should be higher than oil phases, or the oil phase will precipitate in low temperature. So the two types of liquids should be mixed at 80.The product of reaction of stearic acid and triethanolmine is O/W emulsifier. The mixture of oil phase and water phase is the process of emulsifiers generation.2. Preparation of W/O emulsion baseMaterialDoseFunctionGlycerol monostearate0.85gOil phaseBeeswax0.25gParaffin3.75gStearic acid0.625gLiquid paraffin20.5gVaseline3.35gSpan 805 dropsW/O EmulsifierCalcium hydroxide0.05gWater phaseEthylparaben0.1gDistilled water20gEssence2 dropsCorrectantAdd glycerol monstearate, beeswax, paraffin liquid paraffin, Vaseline and span 80 and stearic acid into the evaporating dish. Then melt the mixture in 80 of water bath. Calcium hydroxide and ethylparaben are dissolved in distilled water. Then heat if in 80 of water bath. Pour the water phase into oil phase with stirring. Keep stirring when keep the mixture in water bath at 80 for 5 minutes. Then take it out stirring it until it cool to R.M.Results and Discussion1. O/W emulsion baseWhite semi-solid preparation can be got. The O/W emulsion base can be moved from skin easily.2. W/O emulsion baseWhite semi-solid preparation can be got. The W/O emulsion base is moved difficultly from skin. It is more adhesive than O/W emulsion base.The product of reaction of stearic acid and triethanolmine is O/W emulsifier. The mixture of oil phase and water phase is the process of emulsifiers generation. The product has the function of coemulsifier. However, the product of reaction of stearic acid and calcium hydroxide is W/O emulsifier. The types of emulsifier decide the types of emulsion.The amount of water should be mastered, if addingtoo much water, the productwould be toothin. The temperature is important in the experiment. The water should be heated to 80 and add to oil phase，otherwise the mixing is not thoroughly and reducethe products quality. Auxiliary emulsifying aents, such as glycerol monostearate, can help emulsifying agents to emulsify the bases. When weighting the liquid, we can have a scoop under the bottle to measure the amount accurately.ConclusionReferences周建平，平其能.药剂