Doctors and physicians prescribe tablets for most disease conditions.
There are different types of tablets but all of them look similar except in terms of shape, size and color.
But in fact tablets are designed after a through thought by the pharmacists.
They are designed to meet requirements of the patient, disease state, medicine content and other factors.
Hence we can hear names like sustain release tablets, quick soluble tablet, film coated tablets etc.
But few things are common to all of them. When a tablet is swallowed, it gets broken down or starts to dissolve in the body fluids. After dissolution, the medicament inside is released into body fluid in the gut. From there it enters blood and circulates to whole of the body.
Which include the drug ingredients and other substances to enhance the size or mask the bitter taste etc. Tablets are easiest Routes of Medication Administration.
Different Types of tablets:
In broad sense tablets are classified as
- Compressed tablets &
- Molded tablets.
These two tablet types are further classified base on purpose, use and mode of administration as
1. Oral tablets
2. Chewable tablets
3. Buccal or sub-lingual tablets
5. Effervescent tablets
6. Enteric coated tablets
7. Sustained release tablets
8. Vaginal tablets
9. Sugar coated tablets
10. Film coated tablets
11. Layered tablets
13. Soluble tablets.
14. Pressed coated tablets.
Molded tablets: These are of two types as
- Hypodermic tablets
- Dispensing tablets
The main difference is compressed tablets are made on large scale while molded ones are made in very short scale for experimentation or for rare use.
Based on surface Coating of tablets:
a) Film coated tablets: These tablets have a filmy, shiny and very smooth coating on their surface. In most cases, this is meant to see that the tablet is soluble in the intestine rather than in the stomach.
This is done to enhance solubility in basic pH or to avoid damage in the stomach for better availability to the body.
b) Simple or UN-coated tablets: These are routine tablets and as mentioned, they do not have special coatings. These tablets are less expensive than other forms of tablets.
Based on drug release profile:
a) Fast release tablets: These tablets are designed to release the drug ingredients faster than normal.
b) Regular release tablets. These are routine tablets which start releasing the drug once they reach the stomach.
c) Delayed release tablets. These tablets are designed to release the drug over a period if 24 hours. The intention is give a single dose administration for the whole day relief of symptoms. They have high concentration of drug than normal tablets. Also they are quite expensive than other tablets.
Based on route of administration:
a) Oral tablets: These are the tablets which are taken by swallowing along with a glass of water. They are the most common types of tablets.
b) Sub-lingual tablets.: These tablets are meant for fast action in some disease condition like heart stroke. Here glyceryl trinitrate is given as tablet which is put below the tongue. It dissolves faster to release the drug and save the patient from death.
c) Chewable tablets: These are big sized tablets which are difficult to swallow. Hence they are made such that they be consumed by biting and chewing the tablet. Most of antacid tablets are chewable types.
d) Effervescent tablets etc:These are tablets which are meant to be dissolved in water and then consumed. These tablets when placed in water, immediately breakdown to release the drug.
So we have different kinds of tablets but all of them very easy to administer with correct dose. Hence they are widely used. Lets see details of above mentioned tablets.
e) Layered tablets: These tablets are layered or have two or more layer of ingredients. Unlike conventional tablets where we have a single piece of substance molded to shape, here two or more layers of material are aligned into tablet for control release of the formulation.
As we can see in the above image, there are three layers in the tablet. Two white layer and a center reddish brown layer. The layer at the middle has medicament while other two are just to control the tablet dissolution rate and therefore medicament release.
These are the tablets meant to be put in the body sub-surfaces mostly below the skin or into muscles. These implants one inserted into the body tissues, they release the drug slowly over a period of months to year. Drugs like contraceptives, steroids are given in this route. There is no need for regular administration of the drug if these implants are used. But they can cause pain and sometimes release excess drug leading to toxicity.