Overview Of Pharmaceutical Chewable Tablet

Chewable tablets which are required to be broken and chewed in between the teeth before ingestion. These tablets are given to the children who have difficulty in swallowing and to the adults who dislike swallowing. These tablets are intended to disintegrate smoothly in the mouth at a moderate rate either with or without actual chewing.

Chewable tablets

Chewable tablets are often employed when the active ingredient is intended to act in a localized manner rather than systematically. The composition of chewable tablets consists of gum cores, may or may not be coated. The core is composed of an insoluble gum base like fillers, waxes, antioxidants, sweeteners, flavoring agents. The percentage of gum base varies from 30-60%. Mannitol is widely used as an excipient in chewable tablets for its non-hygroscopic nature for moisture sensitive drugs. It is sweet and has a negative heat solution.

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Characteristics Of Chewable Tablet

1. Easy to chew

2. Palatable

3. Small size and suitable shape

4. Easy to disintegrate and dissolve

Excipient

1. Diluent: mannitol, sorbitol, dextrose, fructose and lactose

2. Flavouring agent

3. Sweetening agents: aspartame, glycyrrhizin (magnasweet) and saccharine

4. Colourants

Formulation Requirements Of Chewable Tablets

Many of the formulation requirements for chewable tablets are similar to those of conventional tablets. Powder flow, compactibility, content uniformity, and tablet ejection requirements are dependent on the judicious use of bulking agents (diluents), binders, glidants, lubricants, and anti-adherents.

A major difference in terms of excipients when chewable tablets are compared to conventional tablets is the use of ingredients that address sensory characteristics. Mouth feel factors include sensation and texture. The dissolution of polyols is significantly endothermic, which leads to a cooling effect. Grittiness is influenced by particle size with smaller particles having lower grittiness and being more acceptable.Grittiness can be reduced by using powder particle sizes less than 300 µm. Sticking to the teeth, excessive gumminess, or viscosity and chalkiness are also undesirable.

Mechanical Properties

Chewability may be defined as the ease or difficulty in breaking a tablet by mastication. The FDA guidance on chewable tablets recommends a breaking force upper limit of 12 kiloponds (kp). As breaking force is dependent on tablet size, larger tablets. 

Advantages Of Chewable Tablets

1. Provide quick and complete disintegration of the tablet and thus obtain a rapid drug effect after swallowing and dissolution

2. Easy administration, especially for infants and elderly people.

3. Patient convenience through elimination of need of water for swallowing

4. It has improved bioavailability (which increases dissolution) bypassing dissolution

5. Cheap to produce as it is almost the same procedure with standard compressed tablets

6. Suitable for high strength of drugs and large size of drugs that cannot be swallowed

7. Substitute for liquid dosage form

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Disadvantages Of Chewable Tablets

1. Very bitter drugs cannot be formulated as chewable tablets

2. Need special storage as it is hygroscopic

3. Prolonged chewing of tablet causes sore mouth and painful muscle

4. Chewable tablets can interfere with dentures, so elderly patients always avoid taking them

5. Chewable tablets have insufficient mechanical strength than the conventional tablets, they need to handle carefully

6. Chewable tablets contain sorbitol which causes diarrhoea and flatulence