Study Set Content:
is the internal resistance that a fluid faces against flowing freely.
Absolute viscosity
the ratio of viscosity of a solution containing a solute to the viscosity of the pure solvent.
Relative Viscosity
the property of becoming less viscous when subjected to an applied stress.
Thixotropy
a term that denotes the covalent or noncovalent interactions between two or more compounds that is capable of independent existence.
Complexation
a molecule that interacts with another molecule, the substrate, to form a complex.
Ligand
can form complexes with other small molecules or with macromolecules such as proteins.
Drug molecules
can lead to beneficial properties such as enhanced aqueous solubility and stability
Drug complexation
enhanced aqueous solubility e.g.,
theophylline complexation with ethylenediamine to form aminophylline
stability (e.g.,
nclusion complexes of labile drugs with cyclodextrins
Type of complexes:
Metal Complexes
Organic Molecular Complex
Inclusion complex
metal ion constitutes the central atom interact with a base.
Metal Complexes
one site for binding
Inorganic Complexes -
used a catalyst in the manufacture of bulk drugs
Olefin –
– group of metal ion complexes (two or more donor groups) to combine with a metal ion.
Chelates
components are organic molecules and these are held together by weaker forces or hydrogen bond
Organic Molecular Complex
acidic drugs to caffeine
Drug and caffeine complexes
example of acidic drugs to caffeine
(benzocaine, procaine, tetracaine
2 Polymer types –
PEGs, CMC
a strong acid form complexes with weak bases; to strong base to form salts
Picric acid types
obtained by mixing alcoholic solutions of equimolar quantities of hydroquinone and benzoquinone.
Quinhydrone types –
