Active Pharmaceutical Ingredient

The active pharmaceutical ingredient is the main component of any dosage form that is pharmacologically active & provides desired therapeutic effects.

Active Pharmaceutical Ingredient Definition

The active pharmaceutical ingredient also known as API is the ingredient which is a biologically active part of the medicines or pesticides & produces the desired effect.

Component Of Dosage Form

The finalized form of a finished product is known as the dosage form. Dosage form consists mainly of two components which are given below,

  • Active Pharmaceutical Ingredient
  • Excipients

As we discussed earlier, active pharmaceutical ingredients are the main component which provides a therapeutic effect.

The ingredients in dosage form other than active pharmaceutical ingredients are known as excipients.Excipients are inert and provide no pharmacological effect.

Read About

Role and Classification of Excipients.


To understand the concept of Active pharmaceutical ingredients, take the simple daily life example of medicines used to relieve pain or fever.

If anyone is suffering from fever he or she usually takes a dosage form containing paracetamol. Paracetamol or acetaminophen is the active pharmaceutical ingredient (API) which provides us relief from fever & pain.

Strength Of Active Pharmaceutical Ingredients (APIs)

  • Active pharmaceutical ingredients may be divided into two categories one is natural & other is synthetic.
  • Different strengths of active pharmaceutical ingredients are available in the market in the form of various dosage forms.
  • The strength of the active pharmaceutical ingredient in any dosage form decides how strong the effect will be.


Metformin Hcl is a commonly used active pharmaceutical ingredient (API) which is used to control a specific diabetic condition & is available in the following strengths:

  • Metformin Hcl  500 mg
  • Metformin Hcl 850 mg
  • Metformin Hcl 1000 mg


It is confusing for most people who think that the strength mentioned on the finalized packaging indicates the tablet’s weight.But the fact is that tablet strength & tablet weight are two different things.


Take a simple example of Atenolol 50 mg tablets. Here 50 mg is not the weight of the tablet rather 50 mg represents only the quantity of active pharmaceutical ingredient (API) in the tablet.

As we know that along with API,different excipients are also used for manufacturing of dosage form,so tablet weight may be 100 mg or 200 mg depending on the formulation.

Combination Of Active Pharmaceutical Ingredients

A dosage form may contain a single Active pharmaceutical ingredient (API) or more than one active pharmaceutical ingredient in the same dosage form to provide a therapeutic effect.


Metformin Hcl & Sitagliptin phosphate are two commonly used active pharmaceutical ingredients in a single tablet.

Manufacturing Of Active Pharmaceutical Ingredients

Manufacturing of Active pharmaceutical ingredients is a complex process where different types of compounds or raw materials are used to form APIs.The byproducts which are formed during the manufacturing of API or active pharmaceutical ingredient are known as intermediates.

Taste Of Active Pharmaceutical Ingredients

Different active pharmaceutical ingredients may have different taste which may be one of the following,

  • Bitter
  • Sour
  • Metallic
  • Saltish
  • Astringent

To mask the taste various techniques & excipients are used depending upon the type of dosage form.Tablet coating is one of the simplest examples of taste masking technique.

Examples Of Active Pharmaceutical Ingredients

Following are some examples of commonly used active pharmaceutical ingredients,

  • Diclofenac Sodium
  • Acetylsalicylic Acid
  • Ciprofloxacin
  • Omeprazole 
  • Valsartan
  • Levofloxacin

Also Read

  1. Potency calculation of Active pharmaceutical Ingredient.
  2. Reconciliation in pharmaceutical industries.
  3. How to calculate Batch Size?
  4. Role of diluents in tablet granulation.