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46 Cards in this Set
- Front
- Back
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What preservatives are used in products for external use
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Chlorbutol, Chlorocresol, Chlrohexidine acetate
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What preservatives are used in products for oral use
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Benzoic acid, Compound hydroxybenzoate solution, sodium benzoate
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What are suspensions and why are they used
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Suspensions are used when the API is not soluble for various reasons and therefore is present as suspended particles. The API may be more orally bio-available in this form.
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What is a diffusible solid
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Light powders that are slightly soluble and therefore don't require a suspending agent.
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What is an indiffusible solid
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Heavy powders that are insoluble and that therefore need a wetting or suspening agent to prevent them from sinking (alcohol, glycols, polysorbates).
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Light kaolin, light magnesium carbonate, magnesium trisilicate
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Diffusable solids
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Aspirin, Calamine, Chalk, zinc oxide
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Indiffusable solids
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Suspending agents
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Polysaccharides: Tragacanth powder, Acacia, alginate,
Clays: Bentonite, Silicate Synthetic: Carbomer, Carbopol |
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Dispersion.....
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require no suspening agent and therefore relies on the ability of shaking to redisperse.
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How are suspensions prepared
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Soluble powders are dissolved in vehicle. Insoluble powders are added to a mortar and pestle with vehicle through geometric progression to form a paste. Both forms are transferred into pre-calibrated bottle and made up to volume.
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Are the difference between suspending agents and emulsifying agent
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They are the same except emulsions can have surfactants used as they are composed of two immiscible liquids.
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Types of surfactants
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Cationic: Cetrimide
Non-ionic: Cetomaragol Anionic: Sodium stearate, Calcium ateate |
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Antioxidants
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Butylated Hydroxyltoluene (BHT), butylated hydroxyanisole (BHA)
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Emulsion Stabilisers?
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Ions in creams (Mg2+), etc
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What can go wrong in liquid formations ***
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Solutions: Precipitation forms
Suspension: Sediment gets stuck on bottom (caking) Emulsion: Cracking All Liquids: API degrades & microbial growth occurs |
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What is the difference between syrups, mixtures, elixirs and lintus
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Elixers are potent solutions with a high proportion of ethanol, syrup, glycerol and flavouring. Linctus are for the treatment of a cough and are solutions containing high glycerl and syrup. Mixtures either have the API suspended or dissolved in solution. Syrups contain high concentration of syrup.
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What are labels K and L and how are they different
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Label K 'For external use' implies that is used on skin whilst Label L 'Caution: Not to be taken' aplies to mucous membranes.
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What are the four different types of liquids used externally and how do they differ?
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Applications are applied to the entire body without friction. Liniments are applied to the body with friction. Lotions are applied to a region without friction generally for the purpose as an antiseptic eg. Calamine lotion. Paints are applied to mucous membranes and have a volatile vehicle.
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What are four examples of drugs that would have Label L on them
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Gargles & Mouthwashes
Irrigations Nasal sprays Eye Drios |
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What are three method of sterilisation
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Autoclaves
Heating with bactericide Filtration |
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How does autoclave sterilisation work and what type of products are used
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The autoclaves sterilizes all ingredients by heating at 112 degrees by 15 minutes. The autoclave can only sterilise heat stable products
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Heating with bactericide
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Method of sterilisation where products are heated at 100 degrees for 30 minutes.
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Filtration
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A filter measured at 0.22 microns has substance flown through it to filter any bacteria
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What is the function of external semi-solid preparations
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1. Surface treatment
2. Treatment of epidermis 3. Treatment of appendages 4. Systemic treatment |
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Name four different bases used in ointments
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1. Hydrocarbon bases
2. Absorption bases 3. Water-miscible bases 4. Water soluble bases |
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Whats the difference between a water-miscible and water-soluble base?
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Water-miscible are more occlusive and require an emulsifying agent such as ceterimide (cationic), Cetomacragol (non-ionic). Water soluble bases are soluble into the skin and are non-occlusive. They are easily washed off and a very unstable with many chemicals.
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How do you make an ointment
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1. Determine all melting points of liquid products. Start by melting the substance with the highest melting point in a crucible
2. Stir all melted liquid components together until a thick ointment is made 3. Add the dry ingredients to this through geometric progression on a mixing board. |
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What are the two types of creams?
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As creams are emulsions they can either be water in oil (beeswax, wool fat, etc) or oil in water (anionic, cationic, non-anionic).
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Two different types of gels?
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1. Organogels: Use organic components as the base (ethanol).
2. Hydrogels: Use aqueous components as the base (water). |
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What factors affect drug solubility
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Temperature
Melting Point Polarity Surface Area |
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Is phenobarbitone or phenobarbitone sodium more soluble
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phenobarbitone sodium because it is a salt, therefore making it ionised and more able to make ion-dipole bonds with water
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What does pHp measure?
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The pH in which the drug will be unionised and therefore form a precipitate in solution
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What is salting out?
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Precipitation due to changes that aren't pH related.
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When is the buffer capacity the greatest
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When pKa is closest to the pH which is when the concentration of salt equals concentration of acid.
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Acetate Buffer
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Weak acid. 3.8 - 5.8
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Phosphate buffer
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Weak acid. 5.8-7.8
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Borate Buffer
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Weak base. 8.2-10.2
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Citrate buffer
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Weak acid. 8.2-10.2
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What factors make buffers important
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Drug stability, Therapeutic response, Tissue irritation, Solubility
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What is partitioning?
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The movement of particles between two immiscible liquids
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What do the pH partition hypothesis state about weak acids and bases
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Weak acid will dissociate in the stomach as there is a higher degree of unionised drug at the pH. Weak bases will be absorbed in the duodenum because this is where there is a higher percentage of unionised form.
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What is the effect of non-polar drug in cosolvent solution
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A non-polar drug is a drug that is less polar than water (P=-4) and the cosolvent (P=>-4). This results in increased solubility as the polarity of the solution changes from -4 and moves closer to the solvents polarity which is similar to the drug
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What is the effect of a polar drug in a solvent solution
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A polar drug in a cosolvent solution results in a decrease in solubility as the polarity of the solution moves away from the polarity of the drug
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What is the effect of a semi-polar drug in a solvent solution
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A semi-polar drug has a point in which the drug has optimal solubility due to the polarity of the drug and solution being similar then there is a decrease after this point.
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When is the super-saturation phase reached?
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When the dilution line and the solubility curve overlap.
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How is super-saturation prevented
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- Creating formulations that won't precipitate
- Injecting slowly make it go through the phase faster. |
