Manufacturing of coated tablets is an art , now days with the automated coating process which are available where one can set up parameters for spraying of coating material over tablets bed in coating pan , and one can rest aside by putting the parameters on computer controlled process , still the the operation requires skill and complete understanding of the process and the want of coating .
Why a tablet is coated , Scientific reasons besides look and elegance
Coating a tablet impart good and beautiful looks besides coating is many times it is requirement of dosage form and molecule which is to be given to patients , coating provides extended self life and protection with respect to physical and chemical properties of drug molecule
Tablets are coated to make the formulation a controlled release , or one can put a drug in coating material to modify the release of drug.
Enteric coating is a coting which do not dissolve in gastric juice , because coating material is acidic nature , and the coating material too is of acidic composition which do not dissolve in acid , and gets dissolved in base as it is a acid , a simple reaction as that of acid base takes place over here and this coating material dissolves in base, this property of coating materials make them good for tablets coating which require resistance in acidic medium .and up on reaching intestine where there is basic PH , the coating material dissolves and releases tablet content , here drug is protected from acid , and absorption too can be more from intestine for given drug molecule. pharmaceutical validation
Coating a tablet can provide a mean for separating two incompatible drugs , one in core of tablet and other in coating material over tablets, here one can achieve controlled release of particular drug by coating a sustained release tablet which requires release of a drug over next 24 hours , steadily and some immediate dose of drug can be incorporated in coating material . some drugs were added in coating material in multivitamin tablets example folic acid in sugar coated tablets it is added in tablets coating material.
Tablet coating can be achieved by coating of tablets by either film coating material or sugar coating.
Film coating is preferred one over the sugar coating as sugar coating is lot of time consuming and a lengthy process.
Where as film coating is very easy process, earlier it required non aqueous solvents to be used for dissolving coating material .
There are some companies which provide ready to use coating material for tablets of all size and shape and in variety of colours and shades , with your requirements you can ask these coating material providers to develop coating material for your tablets as per your requirements.
More over these coating materials do not require non aqueous solvent , you can use purified water as solvent for these coating materials .
This reduces cost of your tablets formulation.
They produce equally elegant and effective coating with aqueous solvent.
Pharma process validation
Tablets coating process is a complex process and depends on many factors like available equipments , aria , and coating material.
A good coating material will always over weigh on many factors as some coting material manufacturing companies do consider the equipments and facility constrains at various costumers while formulating coating material , the also supply customised formulations only for a particular customers.Pharmaceutical Process Validation