Solutions Flashcards
What is a solution?
A mixture of 2 or more components that form a single phase that is homogeneous down to the molecular level
Is there crystallisation in solutions?
No
What are advantages of solutions?
Drug is uniformly distributed
Uniform dose when measured accurately
Absorption is not delayed as drug is already in solution
Easy to swallow
Why is sugar used in solutions?
Sugars stop bacteria functioning and act as a preservative by osmosis
What are disadvantages of solutions?
Generally less stable than solid dosage forms
Difficult to flavour mask
Bulky to carry - lowers compliance
Spoon or syringe required for accurate dosing
Pharmaceutical uses of solutions
Nasal
Eye drops
Ear Drops
Enemas
Oropharynx
What are polymers?
Long chains of low weight molecules
What are the 3 classes of polymers?
Natural, semi-synthetic and synthetic
Examples of natural polymers
Polysaccharides - cellulose and starch
Proteins - Collagen and gelatine
Examples of semi-synthetic polymers
Cellulose ethers - cellulose fibres with methyl groups added
Carmellose
Examples of synthetic polymers
Poly(acrylic) acid -carbomer
Poly(ethylene oxide) - polyox
What effect does Carbomer have on a solution?
Large viscosity enhancement
How does Poly(ethylene oxide) work?
H bonding between COOH prevents dispersion
