8 to 10 inch bed to gun distance
Importance of gun to gun distance?
yes 5-6 inch
Which is more critical of following
API coating
Film Coating
Enteric Coating
Sugar coating
Can a sugar coating be Enteric Coating?
yes sugar coating can be enteric coating. it is also known as enteric sugar coated tablet.
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How to mask tha taste of API if coating sol containing API has bitter taste?
Ans is as follow
API
Sugar
Enteric
Film
gun to gun distance prevent spray overlaping which then prevent sticking twining
What is twining?
How to prevent twining?
Sugar coating can be done for logo/embosed tablet?
What is rat hole?
rat hole occure at which stage?
remedy of rat hole?
Rat-holing is a condition where the material forms a hole or narrow channel above the feed auger or outlet in a hopper while the remaining material is stationary against the hopper wall.
- Since funnel flow will result in a first-in-last-out flow sequence, any side-to-side segregation that occurred when the equipment was filled will often be exacerbated .
- High cohesive strength may result in formation of a stable rathole.
3.Flooding can result in a highly aerated (low-density) powder from a feed system to a tablet press or an encapsulator, which may adversely affect the tablet or capsule properties or become a further source of segregation. - Bulk density variation s.
The first requirement for such a design is the outlet diameter, which should be greater than the critical rathole diameter (Df) calculated from cohesive strength test results, to ensure that a stable rathole will not form. Several equivalent changes can be considered to reduce the potential for ratholing. The outlet size can be increased (within reason, of course, while still allowing it to interface with the downstream equipment), the powder fill height or equipment capacity can be reduced (thus reducing the consolidation of the powder and hence reducing the strength of the material that can give rise to ratholing), or custom equipment features such as agitation and/or mechanical assistance can be utilized. If the option is available, changing (or reformulating) the powder to reduce its cohesive strength can also reduce likelihood of ratholing. Common methods to reduce cohesive strength include increasing particle size, lowering the moisture content, and using a glidant.
If any one of the conditions for selecting funnel flow is not met (e.g., segregation is a concern), or the options available to prevent a rathole are not practical for a given application, mass flow must be utilized.
Design options: mass flow design
Mass flow discharge from a bin, portable container or a hopper occurs when the following two design criteria are meet: - The sloping walls are smooth and/or steep enough to promote flow along the walls;
- The bin outlet is large enough to prevent an arch.
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Reason of twinning-
- High spray rate is over-wetting the tablet.
- Overlapping of spray.
- Atomisation air is low and the coating solution is not dispersed in fine particles
- Exhaust temperature is low to dry the coating solution and twinning occurs.
- Nozzle to bed distance is low leading to over wetting of tablet and finally twinning.
Twinning-Tablets become stuck together, usually after becoming aligned along flat surface
What is reason of film cracking in tablet coating?