Differences between Drug & Dosage Forms

In this article, I will try to discuss one of the most common & confusing questions asked regarding the differences between drug and dosage forms.

I will try to keep the explanation very simple & concise to clear the basic concept. First of all, let's discuss what is a drug.

Drug 

As this article is intended to overview few basic concepts, so i wont dig deep into definitions of drug. I will define drug as:-

A drug is An active pharmaceutical Ingredient which gives biological or pharmacological effects. Any substance which gives a therapeutic effect can be called as a drug.

Example- For the treatment of peptic ulcer disease(PUD) the substance Omeprazole is prescribed, so the substance Omeprazole is a drug or API because it provides therapeutic effects to relieve the symptoms of peptic ulcer disease.

Now let's have a look at what is dosage form but before going into details of dosage form first of all let's talk about a simple definition of Dose.

Dose

The calculated amount of a drug which is prescribed by the practitioner to the patient to take at specified time intervals for achieving desired therapeutic effects is known as a Dose.

Example

Continuing the above example of Omeprazole, if a practitioner prescribes that take 20 mg of Omeprazole two times a day then it is the dose of Omeprazole.

Dosage Form 

As it has been discussed earlier, the drug is an API means purely API is known as drug. So what is dosage form?

The combination of drug and an inert material is called Dosage Form. The inert materials are known as excipients so a combination of active pharmaceutical ingredients & excipients is known as the dosage form.

• API + Excipients = Dosage Form 

Explanation Of Dosage Form 

Read the dosage form with some modifications like reverse reading as given below,

• Dosage Form 

After modification & reading reverse

• "Form Of Dosage or Form Of Dose"

Now lets see the definition of Dosage Form,

• The form of a dose is known as the dosage form.

Or

• The form of a drug is known as the dosage form.

Or

• The physical form of a drug in which it is available in the market to use by a specific route for therapeutic purposes is known as Dosage Form.

Or 

• The finalized form of a finished product is dosage form.

Example

Omeprazole is purely a drug (API) but we know that a patient can not take API alone for therapeutic purposes; it always requires some excipients for its transportation, stability & dissolution.

So, Omeprazole alone is a drug & when we add some Excipients with it, it is converted into a dosage form.

There are different types of dosage forms solid dosage form e.g ,solid dosage  liquid dosage form, semi-solid dosage form, parenteral & inhalation dosage forms.

Many drugs are available in more than one dosage form depending on their physicochemical properties & stability data.

Here If we combine solid excipients with Omeprazole, it will be converted into Solid dosage forms e.g. tablets.

• Omeprazole+Diluents+Binders+Disintegrants+Lubricants & Glidants.

If we use liquid solvents & suspending agents the paracetamol will be converted into liquid dosage form e.g. Syrups

Last but not the least 

Pure API is known as a drug & the physical form of a drug in which it is administered, is known as the dosage form. In the above examples,Omeprazole is a drug or  API & Omeprazole tablets and Omeprazole injection are examples of the dosage form in which it is available.

Dr. Shah Aswad Rahman Choudhury

Assistant Manager, Training

Radiant Pharmaceuticals Limited