extrusion technology
TRANSCRIPT
Extrusion Technology
Extrusion Technology
Introduction
Materials used
Process & equipment
Evaluation
Applications
History
• In 18 th century Joseph Brama mfg. of lead pipe by using
extrusion technology • In 19 th century plastic industry More than half products in plastic industry mfg. by using extrusion process
Introduction Definition :
Process of embedding drugs in polymeric carrier
Or Process of converting a raw material into a product of uniform shape an density by forcing it through a die under controlled condition
Advantages
1. Enhance bioavailability of poorly soluble drugs
2. Absence of water & solvents3. Reduced production time 4. Uniform distribution of fine particles 5. Sustained , modified and targeted release
capabilities
Advantages
6. Wide range of dosage forms
7. Stability at varying pH & moisture level
8. No requirement of compressibility of API
9. Better content uniformity
10. Reduced no. of unit operations
Disadvantages
1. Thermal process
2. Flow property of polymer essential
3. Limited no. of polymers
4. High energy input
5. Not useful for Heat sensitive material
Materials used
1. Active ingredients
2. Polymers
3. Plasticizers
4. Other processing aids
Active Ingredients
1. Low solubility & low bioavailability2. Amorphous material 3. Degrade from hydrolysis
E.g.Lopinavir & Ritonavir, Ritonavir etc.
Polymers
1. Drug – polymer must be miscible2. Stability of polymer 3. Theroplasticity of polymer
E.g. PVP & it’s polymers, PEGs, Cellulose ethers and acrylates
Plasticizers
Function :1. Improve processing conditions 2. Improve physical & mechanical
properties 3. Increase flexibility of extrudates 4. Lowers glass transition temperature ( Tg ) of polymers
E.g. Sorbitan monolaurate
Other processing aids
1. Rate modifying agents 2. Antioxidants 3. Chelating agents 4. Thermal lubricants 5. Waxes
Basics of machines
Divided in four steps :1. Feeding system2. Screw & barrel assembly3. Die assembly 4. Vacuum assembly5. Downstream equipment
feeding system
1. Controlled flow 2. Volumetric / gravimetric feeder
Screw & barrel assembly
1. Single / Twin screw 2. Barrel assembly
• Heaters • Water line• Temp. probe
Die assembly
1. Die zone 2. Die nozzle
• Shape the final product
Vacuum assembly
Remove water vapour generated during extrusion
Down stream equipment
Cool, convey & break the extrudates
Types of Extrusion machines
Based on type of screw :1. Single Screw 2. Twin screw
Comparison of single screw vs twin screw
Single Screw Twin Screw Mixing capability less Mixing capability more
More residance time Less residance time
Self wiping not done Self wiping screw profile
Not versatile Versatility
Output less More output
Evaluation
Methods differentiate between solid solution & solid dispersions1. Differential scanning calorimetry ( DSC )2. Thermo gravimetric analysis ( TGA )3. X- ray diffraction method ( XRD )4. IR / NMR spectroscopy5. Microscopy
Differential scanning calorimetry
Process :Extrudates scanned with physical mixture of blend
Use :• Study thermal property of materials• Detects transitions ( M.P., Tg )
Thermo gravimetric analysis ( TGA )
Measure thermal induced weight loss of material
Use :• Study of desolvation & decomposition • Thermal stability
X- ray diffraction method ( XRD )
Principle :Based on Bragg's law
Use :• Characterize crystalline property• Differentiate between solid solution &
solid dispersion
IR & NMR spectroscopy
IR Spectroscopy :• Detect changes in bonding between
functional groups
NMR spectroscopy :• Probe the crystallinity of material
Microscopy
Use :To study crystalline property of extrudates
Applications
• Mask bitter taste of active drugs• Increase drug solubility & dissolution rate • Formation of controlled release dosage
form• Formation of targeted release dosage
forms