Introduction
Emulsions are a dispersion system composed of two immiscible liquids or more. One of the liquids is dispersed as small fine droplets throughout the other liquid. Depending on the dispersed and external phases, emulsions can be classified as: water-in-oil emulsions which are fine aqueous droplets dispersed in an oily hydrophobic continuous phase or oil-in-water emulsions which are fine oily droplets dispersed in an aqueous hydrophilic continuous phase. Other types are multiple emulsions which consist of a dispersed phase containing droplets of another phase for example w/o/w or o/w/o. Microemulsions are based on the size of the liquid droplets. These comprise of spherical or cylindrical droplets having a size between 10 – 120 nm (Mehta, S & Kaur, G 2011) dispersed in another phasing using an emulsifier or a mixture of emulsifier in high concentration (15 -25%). Emulsions are thermodynamically unstable due to the large surface area between the two phases resulting in a high interfacial energy. The system will try to lower the energy by reducing the area of contact between the two phases resulting in coalescence of the dispersed phase, droplet size enlargement and eventually phase separation. Therefore it’s important to stabilise the interface between the two immiscible phases. This is done by the addition of an appropriate emulsifying agent. These are amphiphilic surfactants containing both hydrophilic and hydrophobic characters. Therefore they are classified according to the balance of characteristics using the hydrophilic-lipophilic balance (HLB) system. The HLB values range from 0 to 20 on an arbitrary scale with each surfactant having a unique value. The higher region of the scale includes hydrophilic surfactants su...
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...sicochemical Principles of pharmacy, 4th edition, A. T. Florence and D.Attwood (Ed.), Pharmaceutical Press (2006), Chapter 4: Drug stability, pages 93-138.
Martin’s Physical Pharmacy and Pharmaceutical Sciences, 5th edition, A. P. J. Sinko, Lippincott Williams and Wilkings (2006), Chapter 15: Chemical kinetics and stability, pages 397-434.
Francoise Nielloud, F. (2000). Pharmaceutical emulsions and suspensions. [Online access] Google Books. Available at: http: http://books.google.co.uk/books?id=hDOS5OfL_pQC&printsec=frontcover&dq=emulsions&hl=en&sa=X&ei=AnVeU- r0NsnF7Ab8qYG4CQ&ved=0CFUQ6wEwBg#v=onepage&q=emulsions&f=false
Dipak Kumar, Sarker. (2013). Pharmaceutical Emulsions: a drug developer’s toolbag. [Online access] Google Books. Available at: http://books.google.co.uk/books?id=XHgoAgAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
At this point the identity of the unknown compound was hypothesized to be calcium nitrate. In order to test this hypothesis, both the unknown compound and known compound were reacted with five different compounds and the results of those reactions were compared. It was important to compare the known and unknown compounds quantitatively as well to ensure that they were indeed the same compound. This was accomplished by reacting them both with a third compound which would produce an insoluble salt that could be filte...
Craig, D. Q. (2002). Pharmaceutical Applications of Micro-Thermal Analysis. Journal of Pharmaceutical Science, 91(5), 1201-1213.
Firstly, an amount of 40.90 g of NaCl was weighed using electronic balance (Adventurer™, Ohaus) and later was placed in a 500 ml beaker. Then, 6.05 g of Tris base, followed by 10.00 g of CTAB and 3.70 g of EDTA were added into the beaker. After that, 400 ml of sterilized distilled water, sdH2O was poured into the beaker to dissolve the substances. Then, the solution was stirred using the magnetic stirrer until the solution become crystal clear for about 3 hours on a hotplate stirrer (Lab Tech® LMS-1003). After the solution become clear, it was cool down to room temperature. Later, the solution was poured into 500 ml sterilized bottle. The bottle then was fully wrapped with aluminium foil to avoid from light. Next, 1 mL of 2-mercaptoethanol-β-mercapto was added into fully covered bottle. Lastly, the volume of the solution in the bottle was added with sdH2O until it reaches 500 ml. The bottle was labelled accordingly and was stored on chemical working bench.
Pinto Reis C., Neufeld RJ., Ribeiro AJ., & Veiga F., 2006. Nanoencapsulation I. Method for preparation of drug-loaded polymeric nanoparticles. Nanomedicine: Nanotechnology, Biology and Medicine, 2, 9-21
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
An emulsion is the forcing of substances that would not normally mix. In this experiment, multiple oil-in-water emulsions were performed. An oil-in-water emulsion is when there are little droplets of oil dispersed throughout water. The most common type of emulsion includes fats and water. A temporary emulsion was formed from this experiment. A temporary emulsion has to be shaken or mixed in some form to stay together (later on it will separate). This similar idea is used with salad dressings.
12. "Chemotherapy." World of Scientific Discovery. Gale, 2007. Science in Context. Web. 23 May 2014.
Discuss the possible drug and excipient-related constrains of the formulation (no identity of the drug was given to you at this
...Coauthor, ChemBioChem 2006, 7, 1-10; b) A. Author, B. Coauthor, Angew. Chem. 2006, 118, 1-5; Angew. Chem. Int. Ed. 2006, 45, 1-5.))
explain the formation of micelles and bi-layers from lipid amphiphilicity. A variety of books were
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
Analysis of Aspirin Tablets Aim --- To discover the percentage of acetylsalicylic acid in a sample of aspirin tablets. ----------------------------------------------------------------- In order to do this, the amount of moles that react with the sodium hydroxide must be known. This is achieved by using the method of back titration.
Many things change and alter how a hydrocolloid substance reacts. Factors added to hydrocolloid mixtures, such as water depending on the amount, can yield a gel or liquid substance. When heat is added or eliminated, the hydrocolloid mixture’s physical behavior changes. They may thicken at low doses to make a gel substance, some may be used as emulsifiers and others may also be used as whipping agents to create foams. When a hydrocolloid is dissolved in water, the water gathers around and is attracted to the sugar units, forming a layer of water with restricted movement. It is this ability to organize and control water that gives hydrocolloids their ability to thicken and gel. With the exception of gelatin, which is a protein, hydrocolloids are polysaccharides (fats) and or complex sugars (carbohydrates). Which is another interesting thing, Hydrocolloids come in all three forms of nutrients. The properties of any hydrocolloid are based on its physical structure (sugars made from) and its chemical properties: size, charge, and the
Gusdinar T. COMPLEXOMETRIC TITRATION An application method of Inorganic Pharmaceutical Analysis [homepage on the internet] . No date. [cited 2014 Mar 20]. Available from: http://download.fa.itb.ac.id/filenya/Handout%20Kuliah/Inorganic%20Pharmaceutical%20Analysis%202008/English%20Version/05.%20COMPLEXOMETRIC%20TITRATION.pdf.
V. Amarnath, D. C. Anthony, K. Amarnath, W. M. Valentine, L. A. Wetterau, D. G. J. Org. Chem. 1991, 56, p. 6924-6931.