1106806
Description
Flashcards by jenny schneider, updated more than 1 year ago
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Created by jenny schneider
over 10 years ago
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| Question | Answer |
| True or False: crystalline solids are made up of repeating lattice units called unit cells | True |
| Amorphous solids have a regular repeating arrangement of molecules in their structure True or False? | False |
| What does crystal habit describe? | The external shape of the crystal |
| What effects that are important to pharmaceutics can crystal habit have? | different shape crystals may cause problems with flow of powder (e.g. from hopper in tableting) ability to inject a suspension will be harder with needle-like than plate-like shape crystals crystal habit can affect the ease of compression of solid into a tablet |
| What do we mean by polymorphism of a drug | drug can exist as different forms that have different INTERNAL arrangement of molecules in the crystal |
| What is one technique we can use to detect polymorphism of a drug? | X-ray diffraction |
| What effect can polymorphism of a drug have? | Different polymorphs of same drug have different MP, solubility changing from one polymorph to another in a formulation may therefore change solubility and affect bioavailability |
| In general, if you have a hydrate form of a drug and an anhydrous form (anhydrate) which will be more soluble? | anhydrate form |
| If you had a crystalline form of drug and an amorphous form of the same drug, which would usually be more soluble? | amorphous form of drug |
| True or False co-crystals are two crystals of same drug joined together | False: a co-crystal is made of drug plus another molecule which is usually H bonded to the drug |
| True or False A polymer consists of repeating units of small molecules called monomers | True |
| Properties of polymers will vary with MW e.g. PEG 400 is liquid and PEG3350 is a solid | True |
| Why would a drug be prepared as a solid dispersion? | Solid dispersions are used to help improve the bioavailability of a poorly water soluble drug |
| Explain what happens when we have a simple eutectic mixture | When we mix drug A and B together, they lower each others melting point. At a particular mix, the lowest melting point of mixture of A and B is reached (called eutectic point) |
| Give an example of a eutectic mixture | Here are two: menthol and camphor prilocaine and lidocaine (used in EMLA cream) |
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