Way ahead in pharma solid dosage form coating technology

Ideal Cures has put a lot of emphasis on energy savings while launching the 4th generation tablet film coating system. An outlook by Suresh Pareek, Managing Director, Ideal Cures, Saryu Pareek, Sr Vice President – Corporate, Ideal Cures and Laxmikant Sadafule, Vice President – Sales and Marketing, Ideal Cures

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Suresh Pareek

The prospect of climate change is alarming and is widely attributed to global warming. This calls for an action to conserve energy and maximise output with minimum input. Individuals and companies are putting a lot of emphasis on energy savings, it not only saves money but also our planet As a part of the initiative to conserve the environment, Ideal Cures has launched the 4th generation tablet film coating system, which reduces the process time drastically and at the same time utilises less energy which certainly helps to reduce CO2 emission.

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Saryu Pareek

History tells us, the first coating of solid pharmaceutical dosage forms began in around the 9th century B.C. with the Egyptians. During the initial days, the solid dosage form was called as ‘Pill’, a spherical hand-shaped (pill) which contains active ingredient, sugar and other diluents. The other excipients that were used for coating were sugar, talc and gelatin. Silver and gold were also used. Many of these coatings proved to be impervious to acid attack in the digestive tract; as a result, the pill never released its active drug completely and was thus ineffective.

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Laxmikant Sadafule

The candy industry was the first to develop and enhance the art of coating. The first sugar coated pills was produced in Philadelphia, US, in 1856. The enteric coating system was developed in the 1880’s. In 1953, the first compression coated tablet was introduced and 1954 saw the first film coated tablet being marketed.

The coating technology primarily has three components coating material, solvent system and machineries used for the coating.

Components in coating evolution

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Spraying process with INSTACOAT 4G

Initially, pharma companies developed coatings in house, but slowly the trend for ready-to-use film coating caught on due to increased productivity, efficiency and time savings. One of the most popular polymers for coating has been hydroxy propyl methyl cellulose (HPMC). Various reasons for its popularity are safety, tried-tested for a long time, film strength and its film forming property. Initially, low viscosity of HPMC E-15 was the most popular polymer for in-house coating system. With HPMC E-15, the challenge was the coating process time because of five to eight per cent solids in non-aqueous solvent systems. As productivity started becoming a concern the ready-mix concept was preferred by the companies. This concept reduced product development time, enhanced consistency in coating, simplified inventory management and also had other advantages. Ideal Cures launched their first ready mix product in year 1999 with the first generation coating material brand named INSTACOAT. The next step was launching the second generation coating products with combination of different polymers including low viscosity HPMC grade and with different combination of polymers like HPMC-HPC, HPMC-Polysaccharides.

After the formulation of multi component systems, the next generation of film forming polymer came up: polyvinyl alcohol (PVA). PVA is a film-forming agent produced by the hydrolysis of polyvinyl acetate. An alkali metal or inorganic acid is used as a catalyst in methanol, ethanol or a mixture of ethanol and methyl acetate, to accelerate the hydrolysis of polyvinyl acetate to yield polyvinyl alcohol (PVA).

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Conventional pan

PVA is used as film forming agent in a number of pharma formulations. INSTACOAT EHP 250, an optimised instant release film coating formulation based on PVA brought revolution in pharma coating. INSTACOAT EHP 250 can be applied on the tablets with a solid content of up to 25 per cent, which is a major step towards achieving highly efficient film coating processes. Besides the increased solid content of the formulations, other properties, like reduced permeability of water vapour or oxygen through a film, have also been achieved.

Another important component in coating technology is the solvent system used. Historically solvents like acetone, benzene, carbon tetrachloride, chloroform, IPA, MDC etc. have been used in pharma coating process. As the regulatory requirements started getting stringent, organic solvents were avoided due to its disadvantages like safety, carcinogenicity etc. Then first choice for non-aqueous solvent which were widely used in past was the combination of Isopropyl alcohol (IPA) and methylene chloride. Next, methylene chloride was eliminated and the concept of hydro-alcoholic coating system evolved and came to be used widely with different ratios. Currently, the preferred choice for a solvent is only aqueous. The reasons for this being safety, cost benefit and a reduction in carbon footprints.

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Autocoaters

Machinery revolutions have played an important role in the evolution of coating system. It was started with the conventional coating pan with external air blower and external exhaust system. Looking at the productivity demand, different sizes of conventional coating pans were introduced like 30, 36, 40, 42 inch etc. There was a huge demand for the machines which could produce good quality, consistent coating along with increased productivity, then the generation of autocoaters came into existence with different capacity, which were completely closed side vented pans fully automated. The bigger pan size available in autocoater were 67/72 inch, still there was a demand for high productivity and the latest innovation we have is the continuous coater, the machine in which feeds the core tablets from one end and the cores are coated before they reach the other end.

The coating process consumes a lot of energy and this energy consumption takes place during the following phases. They are inlet air, heating the tablets, heating the machine, heating the solution, during evaporation of the solvent, process loss, exhaust air, during pan rotation, room HVAC system.

Thus each of these steps generates heat and causing CO2 emission. Reduction in time required for each of these processes is to have higher solid content coating product requiring less time on the coating cycle.

With an increasing emphasis on optimisation of process times and energy consumption, the 4th generation of film coating product was developed targeting an improved coating efficiency. An example of this new generation is INSTACOAT 4G, which is obtained by layering polyvinyl alcohol on a plasticiser backbone. Due to the lower viscosity compared to all previous film coating materials, INSTACOAT 4G can be applied in concentrations of 35 – 40 per cent.

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Continuous coater

The beauty of this product is that one doesn’t have to go for any special or new equipment. This product can work in any machine like conventional coating pan, autocoaters, continuous coating machine, bottom spray for pellet coating etc. There is absolutely no need for any additional investment.

If we compare the process time with the conventional coating products from other suppliers which offer products from 11 per cent solid content up to 25 per cent solid content INSTACOAT 4G at 35–40 per cent solid levels, almost reduces the process time by half. Due to low process time the total energy consumption required is drastically reduced to half, which in turn saves money, lowers CO2 emission and increases the capacity of the plant. INSTACOAT 4G is the perfect fit for high volumes and where there is time constraints for tablet coating.

The pharma industry has the opportunity to use the INSTACOAT 4G to save the money and also to reduce the CO2 emission. Ideal Cures is dedicated to save the environment by helping its customer by providing the economical and ecological value added products which helps them to grow and increase profitability.