Consumer trends driving innovations in tablet coating

Consumer trends driving innovations in tablet coating

Suresh Pareek and Chetan Rajsharad

In modern consumer oriented world, majority of the innovations are consumer driven except some academic research or conceptual development research. In a growing economy like India, all industrial research is based on consumer requirement; either the demand already exists in the market or the demand is created by introducing new ideas or products wherein the consumer is driven to consume that product to get certain new benefits.

The success of any new product, therefore, depends on how well the consumer demand has been understood by the industry or how well the consumer has been told the advantages of newly developed product so that the consumer is motivated to make the first buy of the offered product. Further demand or repeat buying will happen only when the product meets or exceeds the customer expectations, for which the product must perform what the manufacturer had advertised. It is, therefore, very obvious that whenever one undertakes the development of a new product, one must visualise the vacuum in the market place for a new utility, service or product, the customer expectations from that product, develop the product accordingly and test it in-house for the desired features, advertise the product, highlighting all its benefits, follow-up the market reactions after initial sales and make necessary adjustments in salient features, product composition, product quality or the marketing strategies accordingly.

Tablet coating is a very niche market but is very demanding, as not only it demands for high quality products but is also associated with high level of service. At Ideal Cures, we have followed a new product development strategy and have come out with following results:

  • There exists high level of competition in tablet coating as there are already many players in this field. Majority of them offer similar products with little variations and not much innovations

  • The associated service level varies very significantly

  • Though the industry is striving for aqueous film coating, a large number of pharma manufacturers still use organic solvent based coatings

  • The coating products available in market for aqueous film coating demand highly efficient coating machines

  • Pharma manufacturers, (small scale and some medium scale companies) do not have enough resources to go for such efficient but very expensive coating machines

  • Industry still wishes to convert everything to aqueous coating as the cost of organic solvents is increasing everyday. Being responsible corporate citizens, everyone wishes to avoid toxic and harmful solvents for safety of their workers and make small contribution towards reduction of carbon

    load in the atmosphere.

Thus, it is very obvious that there exists a serious vacuum for high performance aqueous film coating products which can work with the existing coating set-ups available in most of the plants—either as such or with some rectifications—but certainly not by replacing the available machinery. This kind of consumer trend analysis leads to the innovations and has forced the R&D team of Ideal Cures to innovate a new product range which has been termed as INSTACOAT ALTIMATE.

The new product works at 25-30 percent solids content in aqueous medium (the solid content in the coating suspension can be varied depending on the available machinery). It dries very quickly, the tablet bed temperature requirement is 36-4000 C as compared to 40-4500 C for existing products; hence, require less energy during coating operation and can easily work even in conventional coating set-ups. It has high film adhesion and improved gloss level and fairly good barrier properties for improved product stability and shelf-life (product can easily be used for moisture sensitive drugs with a coating weight gain of nearly four percent w/w, for normal applications 2.5 percent coating weight gain is enough). It also has faster coating. It gaurantees insignificant change in DT of core tablet (increase in DT is only one to two minutes). It has all colour shades possible using approved colours. It complies to all regulatory requirements and has no patent infringement issues; patent application is already filed. It is highly cost efficient.

From the table we can see the saving in coating time and solvent quantity—the product has been extensively tested and is now available to pharmaceutical industry.

To go with the consumer trend (to convert majority of the coatings to aqueous), we have also devised a ready-reconer for efficient aqueous coating which will further help the industry to achieve its objectives.

Time and organic solvent saving chart in film coating

Calculation for 120 Kg batch size in 48′ Autocoater with 2.5 percent actual weight gain on tablets.
Considering the 20 percent loss during coating so Instacoat Altimate required is 3 percent i.e 3.6 kg

Sr.No.

Description

Solvent type

Reconstitution Level

Calculation of Total solution

Total Spray rate

(gm/min)

Time taken for coating (min)

Min/Max saving in Time (min)

Material (in Kg)

Water (In Kg)

IPA/MDC (In Kg)

Total solution

(gm)

1 * Coating material In House or Ready to
use coating material
Aqueous  
Type A 11% 3.6 29.13 Nil 32730 120 273 77 Minutes
Type B 15% 3.6 20.4 Nil 24000 120 200  
Type C 20% 3.6 14.4 Nil 18000 100 180 72 Minutes
Hydroalcoholic 9% 3.6 18.2 18.2 40000 140 286  
Organic 5% 3.6 Nil 68.4 72000 300 240  
2 Instacoat Altimate Aqueous 25% 3.6 10.8 Nil 14400 150 96  
Hydroalcoholic 17.50% 3.6 8.49 8.49 20580 190 108  
  Savings in Organic Solvent Quantity per batch in Aqueous 68 kg      
  Savings in Organic Solvent Quantity per batch in Hydro Alcoholic 60 kg      
* Reconstitution level and spray rate for inhouse or ready to use coating material has been taken as per the actual use in various pharma companies as well as information available from published litrature.

Tips for efficient film coating:

  • Ensure that the coating suspension is free from foam, do not spray the suspension with foam. For making foam free suspension, use the propeller stirrer (with speed control) instead of high shear mixer or emulsifier

  • Select the coating pan with suitable capacity, the tablet charge should be 80-100 percent of the coating pan capacity. Do not use smaller lots in much bigger pans which may result in uneven coating, poor coating efficiency as well as poor energy utilisation

  • Check the tablet mixing in the coating pan before starting the spray. If the tablet rolling is not uniform (tablet stopping in between or skidding in the pan), increase the number of baffles. Improper mixing will result in uneven coating

  • Ensure that the compressed air used is free from oil and condensed water droplets. The compressor tank should be emptied every day before starting the coating. Install suitable filters along with the pressure gauge in the compressed air line

  • Check the overall spray rate as well as spray rate from each gun (in multi-gun system) before actually spraying onto the tablets

  • Ensure the maximum inlet air volume from the hot air blower, with high air cfm, the air temperature can be reduced to the moderate level (55-6500 C) and still getting high drying efficiency. Working at low cfm and high temperature can lead to spray drying

  • Ensure that the variation in drying air temperature is minimum (should not be more than +200 C, preferable within +100 C) for uniform drying of the tablets. High variation leads to uneven drying, whereas the spray rate remaining constant, resulting in occasional wetting of the tablets

  • Be very careful during the initial stage of coating and ensure that there is no possibility of solvent retention inside the core. The core tablet is porous in nature, therefore, can absorb the solvent form the coating suspension if the drying is not sufficient. This retained solvent can get entrapped inside the core by further coating on the surface and may spoil the product over a period of time.

  • Check the spray rate after every 20-30 minutes so as the monitor the uniform spray rate during the whole operation. This can easily be done by putting the solution holding tank on a digital balance and recording the balance reading at specified time intervals

  • Make a log sheet for film coating operation where all the critical parameters (hot air temp, exhaust temp, tablet bed temp, pan speed, air pressure, pump speed, spray rate, avg. tablet weight etc.) are recorded at regular interval (20-30 minutes), this will give the clear picture of the whole operation which may last for two to four hours (the log sheet could be similar to the one used during compression operation). Such data can help in getting the reproducible results batch after batch.

(Suresh Pareek is the Managing Director and Chetan Rajsharad is the General Manager-Technical with Ideal Cures, Mumbai, India)