Crystalline Solids - Solvates

Pseudopolymorphs

Solvates aka

Solvates

occurs wen residual solvents are trapped in the crystalline lattic

Hydrates

when water is the solvent of crystallization

Anhydrates/Anhydrous

crystals with no water of crystallization

Hydrate to anhydrous

CuSO4•5H2O(Blue) VS anhydrous CuSO4(ash)

Higher aqueous solubulity

Anhydrous crystals usually have _______ than hydrates

neutral drug/API + Conformer

Pseudopolymorphs =

neutral drug/API

The first component of Pseudopolymorphs

conformer

The second component of Pseudopolymorphs

Hydrate/solvate

if the conformer or second component is LIQUID at room temperature (e.g. water)

Cocrystal

if the conformer of 2nd component is SOLID at room temperature (e.g. citric acid)

serve as protection from hydrolysis

for beta-lactams antibiotics, purpose of hydrates is to

cyclic amide

B-lactam has functional group

hydrolysis

cyclic amide is prone to

prevent it from further hydrolysis

But for Ampicillin Na.3H2O, being hydrate itself cannot further ask for more liquid hence the purpose of hydrate is to