drug excipient interaction

1. Drug excipient interactions
Mr Santosh S Sarnaik
MS Pharmaceutics
NIPER Guwahati

2. Introduction
Proper design of formulation
Physical interaction
Chemical interaction
Beneficial or detrimental

3. Types
Drug interactions
Drug- excipient Drug – drug Drug packaging

4. Drug excipient interactions
There are two types:
Physical
Chemical

5. Physical interaction
• Affect dissolution of drug
• Example-
1. Cationic drug and anionic superdisintegrants – delayed release
2. Cyclodextrin class ii drug- increase dissolution

6. Chemical interaction
• Always detrimental
• Various types of chemical interactions:
1. Hydrolysis- amide and ester group e.g lactic acid(increases pH)
2. Oxidation- alcohol and aldehyde e.g. benzocaine(silicified)
3. Photooxidation- sunlight or artificial light(Riboflavin)
4. Isomerization- dextro to levo and vice versa(Adrenaline)
5. Mailard reaction- between primary amine and reducing
sugar(isoniazid and lactose)

7. Characterization
• Thermal – DSC, TGA, isothermal microcalorimetry
• Spectroscopic method-FT-IR, ssNMR
• Chromatographic method- TLC, HPLC, HPTLC
• Microscopy- SEM
• Accelerated stability study
• Radiolabelled techniques
• Vapour pressure osmometry