coating suspension preparation, coating suspension preparations, coating suspension preparation for tablets, gujarat, india

Coating Suspension Preparation

Cotab Coating systems are very easy to prepare. Add the cotab powder in solvent /water as described below and mix for 45 minutes with propeller stirrer.

Equipment:	1.	S.S.Vessel with a capacity of 25% more than the total suspension being prepared. The height of the vessel should be around 1.25times than its diameter.
	2.	A variable speed propeller stirrer with blade diameter of nearly 1/3 of the diameter of ss vessel described above.

Procedure for Mixing:

1. Aqueous system:

• Weigh the required quantity of cotab.
• Take required quantity of water in vessel.
• Stir with propeller stirrer to form vortex. Add qty of cotab in vortex, stir for 5 min.
• Reduce the speed of stirrer and continue for 40 minutes.
• Pass solution through 150micron opening sieve & use for coating.

2. Solvent/ Non Aqueous system:

• Weigh the required quantity of cotab.
• Take required quantity of IPA in vessel.
• Stir with propeller stirrer to form vortex. Add qty of cotab in vortex, stir for 5 min.
• Add quantity of Methylene Dichloride and stir continue for 40 minutes.
• Pass solution through 150micron opening sieve & use for coating.

Precautions:

• The usages of high speed stirrer or homogenizer is not recommended.
• The suspension should not be passed through colloidal mill for cotab E Aq.
• The suspension may need gentle stirring during the coating operation to maintain its homogeneous property during spray.
• The suspension thus prepared should be used within 24 hours to avoid any microbial contamination.