Summary
Industrial pharmacy - 1st semester summary
- Institution
- University Of East Anglia
Industrial pharmacy - 1st semester summary Includes bullet points, key diagrams and images
[Show more]
Seller
Follow
Content preview
Pharmaceutical Materials Solid forms- alters bioavailability, stability and manufacturing
Bioavailability- drug in solution, rate limiting step to absorption is dissolution
and influenced by physical form
Polymorphs change the storage and biological effects
Stability- chemical reactivity and conversion to other form
Processing- different flow, compression and water sorption
Regulatory consideration- can patent different forms and new drug is
characterised
Crystalline material- ordered and periodic, unit cell and have a melting point
Amorphous material- no long range order, non-random local structure and have
glass transition (Tg)
Crystal systems- orthorhombic, monoclinic or triclinic
Polymorph Stability
Formed by change in conditions in crystal growth
At given T and p only 1 form is stable (most negative G)
Other forms can be meta stable so kinetically
Monotropic relationship- same form is stable irrespective of T so all will convert
to this form
Enantiotropic relationship- any form may be stable depending on T based on
critical T so can be converted between them
Difficult to tell stable form as metastable may take a long time to transform to
the stable form
True stable form has the highest melting point and lowest dissolution rate
Crystal Formation
Supersaturation of solution by evaporation of solvent- then cool solution
Anti-solvent added-solute has low solubility in
Nucleation- small particles form then crystal grows requires energy until critical
size reached
Crystal growth- molecules diffuse to surface and attach to crystal
Crystal Habit
Tabular
Platly
Prismatic
Acicular
Change in crystal growth (solvent or cooling) can
change the habit but not effects the unit cell
Increase in supersaturation yields longer needles
or thinner plates
Habit- external shape of crystal
Polymorph- internal arrangement of molecules in
crystal
Crystals with different habits indicates presence
of polymorphs
Can effect dissolution rate and flow as change in SA and shape
, Amorphous Materials
No long range order- highly viscous liquids (not completely random)
Preparation- rapid cooling from the melt, fast precipitation from solvent system,
high energy milling or freeze drying
Form when molecules don’t have time to align into a crystal
Glass transition (Tg)- change in molecular mobility
Below Tg- brittle material and low molecular mobility
Above Tg- deformable, reorintational motions possible and no melting transition
Plasticizers lower Tg by increasing molecular motility
Amorphous dissolution- less stable than crystalline so easier to dissolve and
forms supersaturated solution
Rapid dissolution means higher bioavailability
Problems- amorphous materials will recrystallize as thermodynamically
unstable
Hydrates and Solvates
Solvate- crystal contains some of the solvent in its unit cell
Hydrate- crystals contains some water in its unit cell
Solvate formation- crystallise solvent but can happen unexpectedly when drug is
in contact with liquid
Hydrates- different hydrates possible (depends on environment)
Hydrate properties:
Have different melting points, lower solubility and dissolution rate than
anhydrous form
Anhydrous tend to have faster dissolution and higher solubility than hydrate
Hydrates can have higher solubility as water disrupts crystals or the hydrogen
bonds tighten the lattice slowing dissolution
Non-aqueous solvates tend to have higher solubility than anhydrous form
Anhydrous dissolution- endothermic (-ΔH) to break bonds then exothermic
interactions with solvent
Hydrate dissolution- already water interactions so dissolution is lower energy
gain so less driving force for dissolution (ΔG more positive)
Amorphous form can absorb a lot of water but is not a solvate but dissolve
quickly due to instability
Pharmaceutical Powders
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller alexd1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
83637 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now