Complexation classification

1. UNIT - IV
Complexation & Protein
Binding
(CO 4)
By: Ms. Renu Saharan
Assistant Professor
M.M College of Pharmacy
Programme: Pharmacy Course: B. Pharm. (Complexation)

2. Programme: Pharmacy Course: B. Pharm. (Complexation)
MMCP VISION
• “Providing technical and practice oriented pharmacy
education to prepare students with attributes to meet the
need of industry and society”
MMCP MISSION
• To develop best technically competent pharmacy
professionals by inculcating desired attributes in them for
meeting industry demands.
• To make best pharmacists who can practice pharmacy to
become effective team member of healthcare system and
provide optimum pharmaceutical care solutions.
• Promotion of useful and innovative research to contribute in
development of nation and global society.

3. CO & PO (Physical Pharmaceutics I)
Programme: Pharmacy Course: B. Pharm. (Complexation)

4. Introduction
• Complexation is a process where complexes or
coordination compounds are formed which
involves association or interaction of 2 chemical
species.
• Complexation is the association between two or more molecules to form a non- bonded
entity.
• According to the classic definition, complexes or
coordination compounds, result from a donor–
acceptor mechanism or Lewis acid–base reaction
between two or more different chemical
constituents in which neutral molecules or anions
(called ligands) bond to a central metal atom (or
Programme: Pharmacy Course: B. Pharm. (Complexation)

5. Content
• Introduction
• Applications of complexes
• Classification of complexes
• Methods of analysis
• Protein binding
• Methods of determining drug-protein binding
Programme: Pharmacy Course: B. Pharm. (Complexation)

6. Complexe as drugs: Example
• Povidone-iodine(safe & effective antibacterial
and germicidal): polyvinylidone(PVP) is a
water soluble-polymer and forms a water-
soluble complex with iodine.
• Cisplatin
Programme: Pharmacy Course: B. Pharm. (Complexation)

7. Once complexation occurs, physical & chemical
properties of complex species altered which are used to
evaluate to confirm the formation of complexation:
• Solubility
• Stability
• Partition coefficient
• Energy emission
• Energy absorption
• Conductance of the drug
Forces involved in complex formation:-
• Covalent
• Co-ordinate covalent
• Van der wall force of dispersion
• Dipole dipole interaction
• Hydrogen bonding
Programme: Pharmacy Course: B. Pharm. (Complexation)

8. Programme: Pharmacy Course: B. Pharm. (Complexation)

9. Applications of Complexation
1. Physical state: example- nitrogycerine is transformed to its
crystalline inclusion complex with beta cyclodextrine, which is
explosion free.
2. Volatility: in order to stabilize a system or to overcome an
unpleasant odour example- iodine is complexed with PVP.
3. Solubility: example- at low concentration, caffine enhances the
solubility of PABA.
4. Dissolution: example- dissolution rate of phenobarbital is
enhance by using beta-cyclodextrin inclusion complex.
5. Partition coefficient: example- permanganate ions can be
transferred into benzene phase from water phase by complexation
with crown ether.
Programme: Pharmacy Course: B. Pharm. (Complexation)

10. Applications cont…..
6. Stability (e.g. inclusion complexes of labile drugs with
cyclodextrins).
7. Absorption (e.g. Tetracycline with Ca ion form non
absorbable complex)
8. Pharmacokinetics (e.g. protein binding, renal excretion)
9. Pharmacodynamics (e.g. Change drug receptor binding and
so change biological activity).
Programme: Pharmacy Course: B. Pharm. (Complexation)

11. • Physical state
• Volatility
• Stability of drugs
• Solubility
• Dissolution
• Absorption and Bioavailability
• Antidote for metal poisoning
• Antibacterial activity
Programme: Pharmacy Course: B. Pharm. (Complexation)

12. CLASSIFICATION OF COMPLEXES:
Programme: Pharmacy
Course: B. Pharm. (Complexation)

13. Metal ion complexes:
 Metal ion includes the central atom as Drug and it interacts with a base (Electron-pair
donor, ligand), forming co-ordination bonds between the species.
Inorganic type –
 In inorganic metal complexes, the ligand provides only one site for binding with metal.
 The ammonia molecules in hexamminecobalt (III) chloride, as the compound
[Co(NH3)6]3+ Cl3- , are known as the ligands and are said to be coordinated to the cobalt
ion. The coordination number of the cobalt ion, or number of ammonia groups
coordinated to the metal ions, is six. Other complex ions belonging to the inorganic group
include [Ag(NH3)2]+, [Fe(CN)6]4-, and [Cr(H2O)6]3+.
Programme: Pharmacy Course: B. Pharm. (Complexation)

14. Cont…
 Each ligand donates a pair of electrons to form a coordinate
covalent link between itself and the central ion having an
incomplete electron shell.
 Hybridization plays an important part in coordination
compounds in which sufficient bonding orbitals are not
ordinarily available in the metal ion.
Programme: Pharmacy Course: B. Pharm. (Complexation)

15. Programme: Pharmacy
Course: B. Pharm. (Complexation)