Hydroxypropyl Cellulose is a derivative of cellulose and it is used as an excipient in different pharmaceutical dosage forms.USP 32 NF-27 defines the HPC as a partially substituted derivative of cellulose and it may contain not more than 0.6% Silica or any other anticaking agent.
Other Names
HPC is also known
- Klucel
- hyprolose
- HPC
Functions Of HPC
HPC is used as
- Tablet and Capsule Binder.
- As Matrix For Extended Release Formulations.
- Film Former.
- Suspending and Thickening agent
Tablet and capsule binder
HPC or klucel is used as a binder for tablet and capsule formulation for both dry and wet granulation.
- In wet granulation, it may be added in dry mixing before kneading and can be activated by addition of solvent.
- It is also used as a binder for wet granulation in the form of solution.
- The concentration of HPC used as a binder is 2-6% for wet and dry granulation.
Note
HPC is water-soluble but when it is added in water it may form a gel at the start and take time to dissolve to form a clear solution.
Following method can be used to form a clear solution of HPC in water in a short period.
For this slurry of HPC is prepared in hot water or glycerin.
Prepare a slurry of HPC in hot water at 50-60°C and don’t exceed the temperature above 60°C.
Stir the soaking material for a few minutes and maintain the slurry at a temperature, not below 50°C.
Add this slurry in Cold water with slow stirring.
It will produce a clear, lump-free solution in a short period to reduce the binder preparation time of HPC.
(Ref Ashland)
Also Read:
Qualification|FAT|SAT|DQ|IQ|OQ|PQ
As Matrix For Extended Release
- Hydroxypropyl Cellulose is used as a control release agent to slow the release of drugs.
- On contact with water, it forms a matrix and then slowly releases the drug.
- The concentration of HPC used as a matrix is 15-35%.
- As the viscosity of HPC increases, the release rate of drug decreases.
- A surfactant added in the solution of HPC increases its viscosity and drug release is decreased.
Film Former
- HPC is used as a film-forming polymer in tablet coating.
- 5% aqueous solution is used for film coating.
- Film formation by HPC is flexible without plasticiser
Suspending and Thickening agent
HPC is also used as a thickening and suspending agent.
Solubility
- Hydroxypropyl Cellulose is soluble in the water and polar organic solvents.
- It is soluble in the water below 38°C but it is insoluble at a temperature between 40-45°C.
Stability
- An aqueous solution of HPC may promote mould growth so it is recommended to use an antimicrobial agent for aqueous solutions.
- Organic solutions do not promote antimicrobial growth.
Incompatible
Hydroxypropyl Cellulose is incompatible with Methyl paraben and Propyl Paraben.
Grades Of Klucel
Klucel is available in different grades.
7 viscosity types are as follow
- EL
- E
- L
- J
- G
- M
- H
The product name is expressed by a combination letter system.First letter indicates viscosity type then second letter indicates particle size and at the last letter represent market segment e.g
Klucel HF Pharm
H represents grade F Pharm to represent pharmaceuticals.
Fine particle size is expressed by X.
Klucel MXF Pharm
(Ref Ashland)
Following are grades of Klucel
- Klucel HF
- Klucel MF
- Klucel GF
- Klucel JF
- Klucel LF
- Klucel EF
(Ref Handbook of Pharmaceutical Excipients)
Hydroxypropyl Cellulose Low substituted (L-HPC)
Low substituted Hydroxypropyl Cellulose is also known as L-HPC and is the derivative of cellulose which contains less substitution of hydroxypropyl as compared to HPC.
Solubility
HPC is soluble in water but L-HPC swells in water and is insoluble in water.
Other Names
- L-HPC
- Hyprolose
- Low Substituted
Function
Low substituted Hydroxypropyl Cellulose is used as
- Tablet and Capsule Disintegrant.
- Tablet and Capsule Binder.
Grades Of L-HPC
L-HPC is available in different viscosity grades and particle sizes which are as follow,
- LH-11
- LH-21
- LH-31
- LH-B1
- LH-22
- LH-32
LH-11
- LH-11 has long fibrous particles.
- LH-11 is used as a Disintegrant for Direct compression.
- LH-11 is used as an anti-Capping agent for direct compression.
LH-21
- In LH-21 quantity of fibres is less.
- LH-21 is used as Binder in wet granulation
- LH-21 is used as a disintegrant in wet granulation.
Also Read:
Colloidal Silicon Dioxide|Aerosil
LH-31
- LH-31 has a small particle size.
- It is used in the extrusion process to produce granules.
LH-B1
- It is non-fibrous.
- Its density is high.
- It is suitable for FBD process and direct compression method.
LH-22
- Give better disintegration.
LH-32
- Give better disintegration.
Incompatibility
- L-HPC is Incompatible with alkaline substances and formulations containing L-HPC and alkaline substances may result in prolong disintegration time.