Dosage forms exam 1 Preformulation
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If not a solution the drug must be liberated from its dosage form
Drugs must have sufficient____ solubility and _____ solubility
- Water- be in molecular form in body
- Lipid- traverse lipid membranes
Drug properties for preformulation
- Physical properties
Common. Has a repeating arrangement of the individual molecules that creates the crystal lattice.
Crystal habit defined by
The internal structure
Different habits can result from
minor changes in synthetic conditions
No repeating arrangement, molecules are random no crystal lattice... looser arrangement
Important for dosage uniformity
Function of drug dissolution, fraction of administered drug that reaches systemic circulation.
Solid state stability
hygroscopicity and polymorphism
Being in an unstable or transient but relatively long lived state of chem or physical form.
Metastable polymorphs are generally ___ soluble that their _____ stable counterpart. This is due to what?
- more soluble
- More stable
- Weaker interaction
Hydrates or solvates
changes in hydrate form can affect solubility.
T/F Hydrates are more soluble than their anyhydrous counterparts.
Detection of polymorphism is by?
Melting points, different polymorphs= different melting points.
micronization reduced dose by 50%
Crystals were too small, dissolved too fast caused nausea
Particle flow effects
- Mixing and pouring
- Speed of processing during manufacture
- Settling or statifying
Factors for particle flow
Electrostatic, absorbed moisture, density, shape, size.
liquids dissolved in each other
General anesthetic (gas+liquid)
Dissolution of crystalline solute
- 1) remove solute from molecule
- 2) create hole in solvent
- 3) place solute in hole
Amount dissolved per volume
Hydrophilic substituents hydrogen bond with ______
Phenol is 100X more soluble than _____ due to what?
Benzene due to hydrophilic substituents.
corticosteroid ring structure with 2 hydroxyl groups, solubility is 5 mcgrams/mL
Ionization state is one of the most important physicochemical properties.
Affects dosage formulation, absorption, distribution, and excretion.
pH=pKa + log (A-/HA)
- Hendersen hasselbeck
- A- salt
- HA Acid
Weak Acid solubility equation
pH=pKa + Log ([S-So]/So)
Weak base equation
Same but flip the So/[S-So]
What does S and So stand for
- S is overall solubilty
- So solubility in unionized form
Solvent pH affects the drugs
Surfactants and Cyclodextrins are examples of
T/F dissolution is an exothermic process because energy is needed to break bonds in the solid.
Greater heat input generally leads to greater solubility of a solid.
Creation of solid form must consider several properties
Solubility and stability (hydroscopicity and metastability)
Griseofulvin/PEG known for
Significant solubility improvement
Very common method of altering a drug's properties.
How salt is formed:
Salt is crystallized from the solvent
T/F Salt formation is only for increasing drug solubilty.
False, can increase or decrease
T/F A drug in suspension is more stable than a drug in solution.
Decreased drug solubilty can help mask
T/F Propoxyphene napsylate is less bitter than Propoxyphene hydrochloride because it is more soluble.
False! Because it is LESSSSSS Soluble
Salt can improve solubilty thus
Greater degree of interaction with Water molecules.
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