solventless coating techniques can avoid the use of solvents used for coating of dosage form and reduce the cost and time associated with it.

1. SOLVENTLESS COATING
TECHNIQUES
Submitted by:
D.Sindhuja
M.Pharm(Pharmaceutics)

2. SOLVENTLESS COATING:
solventless coating avoids the use of water/solvent or it reduces to very small
amounts and hence it overcomes limitation of conventional coating such as need for
time, energy consuming, drying steps.
RATIONALE:
 Organic solvents used in liquid coating are flammable and toxic.
 Solvent residue in the formulation.
 High cost of solvents.
 Strict environmental and occupational safety regulations.
 Heat and water involved in coating process can degrade the drug.
 Validation of coating dispersion for controlling microbial presence.
 Solvent removal process is time consuming and requires more energy.

3. SOLVENT LESS COATING METHODS
Compression coating
Powder/dry coating
Hot –Melt Coating
Supercritical fluid Coating
Magnetically assisted impaction Coating
Photo curable Coating

4.  COMPRESSION COATING:
PROCESS OF COATING:
o Punches form cup of coating material in lower die.
o Drug is filled in that cup using another modified punch.
o Coating material is compressed on the cup.
MECHANISM:
o The core containing active pharmaceutical ingredients is
compacted with granular materials.
COMPRESSIBLE EXCIPIENTS:
Mcc, lactose, mannitol….
ADVANTAGES:
Two or more dosage forms can be physically seperated
producing tablet with in a tablet.
DISADVANTAGES:
Mechanical complexity, difficult to place the core exactly in
the center of the tablet.

5.  MAGNETICALLY ASSISTED IMPACTION COATING:
The magnetically assisted impaction coating devices can coat
soft organic host and guest particles without causing major
changes in the material shape and size.
MECHANISM:
o Excitation of magnetic particles
o Deagglomeration of guest particles
o Spreading and shearing of guest particles on the surface of
the host particles
o The interaction of magnetic host-host-particles
o Magnetic host wall interaction
o Formation of coated products
ADVANTAGES:
Rise in temperature is negligible.
Most suitable for temperature sensitive materials.

6.  HOT- MELT COATING:
o In hot melt coating method, the coating material is applied in its molten state on the substrate
then solidified by cooling.
o The necessity of the application of any solvent is fully eliminated.
o The choice of the coating excipients depends primarily on its function (e.g., retarding the drug-
release rate, preventing environmental degradation and masking unpalatable taste) in the
dosage form.
Hot melt coating
Fluidized bed coating Spray coating Pan coating

7. “
”
 SUPERCRITICAL FLUID COATING:
o In this method, the coating material is dissolved in supercritical CO2 (has liquid like density &
solvating power, gas like transport properties, low critical temperatue - 31C, pressure - 74 bar) in
which the drug particles are dispersed. The solvent power of CO2 is gradually reduced to enable the
coating material to precipitate onto drug particles.
Advantages:
o Prevent agglomeration of fine particles.
Disadvantages:
o Requirement of core to be soluble.

8. POWDER/DRY COATING:
 PROCESSES:
1. Electrostatic spraying
2. Fluidized bed
3. Electrostatic fluidized bed
4. Flame spray
METHODS:
1. Plasticizer dry coating- adhesion by wetting with plasticizer
2. Heat dry coating- Eudragit E-PO particles were continuously spread onto the tablet
3. Electrostatic dry coating- spraying of a mixture of finely grounded particles and polymers on to a
substrate surface
4. Plasticizer electrostatic heat dry coating-combination of plasticizer, Heat dry, electrostatic dry coating

9. PHOTOCURABLE COATING:
 Photo curing is a chemical approach proposed to rapidly coat tablets at or below room
temperature with an extremely rapid rate.
Major components:
o UV/Visible light source.-efficient in rupturing chemical bonds
o Pre-polymers or monomers-siloxanes and enethiols
o Photo initiators-unsaturated compounds
o Poreforming agents-lactose,sodium chloride
Advantages:
This process can be performed under room temperature.
Disadvantage:
Not suitable for photosensitive drugs.

10. MACHINERY USED FOR SOLVENTLESS COATING:
o Silicon coating machine
o Solvent less laminating machines
o Extrusioncoating machines
o Hot melt coating machines
o Pressure sensitive coating machine
o 5-roll coating machine
o Dry laminating machine

11. CONCLUSION:
The solventless coating techniques mentioned above exterminate numerous drawbacks accomplying with the
conventional solvent based coating mechanism.
Although these methods have greater assistance than conventional coating methods, before commercialization of
these methods further work should be focused on scale-up tests, functional detection of coated solid dosage forms
such as drug release profile and clinical tests to make them more useful, cost effective and safe.
REFERENCES:
Solventless coating-A pliable Technique for future coating prospects, Palllavi.k*, B.Gayathri, K.Chandralekha,
K.Tejaswi, Vignan Pharmacy college, Vadlamudi,Guntur.Pharma Times-vol.47-no.12-december-2015.
Solventless coating for tablets :An alternative to conventional coating technique, Manish Jaimini*,Arpit jain,
Sanjay K.Sharma, Shailender Mohan. Jaipur college of pharmacy,ISI-15,RIICO,Jaipur,Indian journal of
pharmaceutical and Biological research(IJPBR).issue 2,2014.
Review solventless coating technology , Hardhik L.patel*,Hiren B.patel, Chandrababu davuluri, Moin
K.Modasiya. American Journal of Pharmtech Research,vol-1,issue4,2011.

12. THANK YOU