Recent advances in tablet formulation technology
The recent trends in tablet
formulation are:
1.
Versatile immediate release tablet systems
including fast dissolving drug delivery systems, orally disintegrating tablets/
orally dispersible tablets, orally dispersible mini tablets, mouth dissolving/
fast dissolving tablets, novel fixed dose combination tablet ACCU-BREAK
technology inactive layer between two different drug layers), conventional
effervescent, uncoated and film–coated tablets etc.
2.
Modified release tablet formulations
including ring cap coated tablet ALZA, layered tablets (in lay, tablet in tablet,
bilayered tablet), novel chewable sustained release tablet and direct compression
medicated chewing gum.
3.
Excipient technology is advancing to produce
directly compressible materials for both immediate release as in mouth dissolving
systems, or for sustained release systems. The research in excipients is
meeting pace with the high throughput production of tablets. Research is also
advancing into obtaining excipients from natural sources. Various commercial
excipients such as Lycoat, Readily coat, Instamodel and Instanute DR are available
in the market.
Patented Technologies for
Fast Dissolving Tablets
Zydis Technology
Zydis, the best known of the
fast-dissolving/disintegrating tablet preparations was the first marketed new
technology tablet. The tablet dissolves in the mouth within seconds after
placement on the tongue. A Zydis tablet is produced by lyophilizing or freeze-drying
the drug in a matrix usually consisting of gelatin. The product is very
lightweight and fragile, and must be dispensed in a special blister pack.
Patients should be advised not to push the tablets through the foil film, but
instead peel the film back to release the tablet. The Zydis product is made to dissolve
on the tongue in 2 to 3 seconds. The Zydis formulation is also self-preserving
because the final water concentration in the freeze-dried product is too low to
allow for microbial growth.
Durasolv Technology
Durasolv is the patented
technology of CIMA labs. The tablets made by this technology consist of a drug,
fillers and a lubricant. Tablets are prepared by using conventional tableting equipment
and have good rigidity. These can be packed into conventional packaging system
like blisters. Durasolv is an appropriate technology for products requiring low
amounts of active ingredients.
Orasolv Technology
Orasolv Technology has been
developed by CIMA labs. In this system active medicament is taste masked. It
also contains effervescent disintegrating agent. Tablets are made by direct compression
technique at low compression force in order to minimize oral dissolution time.
Conventional blenders and tablet machine is used to produce the tablets. The
tablets produced are soft and friable and packaged in specially designed pick
and place system.
Flash Dose Technology
Flash dose technology has
been patented by Fuisz. Nurofen meltlet, a new form of ibuprofen as
melt-in-mouth tablets, prepared using flash dose technology is the first
commercial product launched by Biovail Corporation. Flash dose tablets consists
of self binding shearform matrix termed as "floss". Shearform
matrices are prepared by flash heat processing.
Wowtab Technology
Wowtab Technology is
patented by Yamanouchi Pharmaceutical Co. WOW means "Without Water ".
In this process, combination of low mouldability saccharides and high mouldability
saccharides is used to obtain a rapidly melting strong tablet. The active
ingredient is mixed with a low mouldability saccharide and granulated with a
high mouldability saccharide and compressed into tablet.
Flashtab Technology
Prographarm laboratories
have patented the Flashtab technology. Tablets prepared by this system consist
of an active ingredient in the form of micro crystals. Drug micro granules may
be prepared by using the conventional techniques like coacervation, micro
encapsulation, and extrusion spheronisation. All the processing utilized
conventional tabletting technology.
Marketed scope in tablet
compression technology
The market for tablet
compression technology and the demands placed on equipment manufacturers have
changed quite significantly in recent years. This has been driven by a number
of factors. Firstly, the pharmaceutical industry has seen a significant shift
of investments in solid dosage production equipment towards generics and
contract manufacturing. As the companies in this segment of the market are, by
nature, strongly focused on cost reduction, a big emphasis is placed on productivity,
flexibility and process yield (i.e., minimal product loss). Equipment cost and
reliability, as well as fast on-site assistance have also become key selection
criteria. research and development based companies have also been forced to
follow this cost reduction trend. Secondly, the meteoric growth of new pharmaceutical
markets in the Middle East and the Far East (e.g., India, China, South Korea)
has led investments in solid dosage equipment in these regions to surpass the
investments made in North America and Europe. This puts an increased pressure
on equipment price and has resulted in several Western based companies moving
the design, manufacture and assembly of their equipment to Asia.
Mottling
Unequal distribution of
colour on the tablet surface with light and dark areas standing out in an
otherwise uniform coloured surface
Cause:
- Variation in the colors of ingredients (drug and other additives)
- Drugs with degradation nature and have different colored degraded products
- Migration of dye to the surface of granulation during drying. At high temperature dyes are easily migrate to surface and spread to upper surface.
- Uneven distribution of colored adhesive gel solutions resulting in precipitation
- The improper size either large or small particles enhances color distribution. During preparation dyes are not properly mixed and not selected ideally or any incompatibility will tends to enhance appearance of color on tablet surface.
- Improper storage conditions.
Remedy:
- By using bright coloring agent that will mask all the color variations of the ingredients
- Proper drying by reducing the drying temperature
- Colored adhesive gel solutions must be added when they are hot too much cooler powder mixtures to avoid precipitation
- It is better to incorporate fine powder adhesives like acacia and tragacanth into product before adding the granulating fluid
- By changing the solvent system or binder system
- Grinding to small particle size
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