Biopharmaceutics Frequently Asked Questions

 What is Biopharmaceutics?

The study of the relationship between physiological, physicochemical and biopharmaceutical properties of API and dosage based on biological performance of drugs is known as Biopharmaceutics.

Biopharmaceutics Consideration of API for Drug Design?

Following are some main important biopharmaceutics considerations for API,

  • Solubility
  • Stability
  • Crystalline Form
  • Particle Size
  • Salt form
  • Impurities
  • Complexation
  • pH & pka
  • Interaction with excipients.

Which Analytical Techniques are used to check API & Excipient compatibility?

Following are some most widely used techniques which are used to study drug excipient interaction or to check compatibility of API with Excipients.

  • Differential Scanning Calorimetry(DSC)
  • Chromatography Techniques as TLC or HPLC
  • Microcalorimetry

Which are the excipients which may result in a Maillard reaction?

Following are some commonly used excipients which may case Maillard Reaction

  • Lactose
  • MCC
  • Starch

What is a Maillard Reaction?

The reaction between reducing sugars and amino acids at high temperature results in brown colouration and this reaction  is known as Maillard reaction.

How many years does a new drug take for its development?

Development of a new drug is a very lengthy process and consists of many stages like preformulation,preclinical,clinical  studies and it usually takes 10-15 years for a successful drug development.

Also Read:

Basics of Pharmaceutics.

What is a Pro Drug?

A pharmacologically inactive drug which after administration into the body is converted into a pharmacologically active drug by metabolism is known as pro drug.


Pro drugs are synthetic derivatives of drugs which have intrinsic pharmacological activity but require transformation in the body to release the drug.

What is the partition Coefficient?

The ratio of unionized drug at equilibrium distributed between aqueous phase and organic phase is known as partition coefficient.

What is Polymorphism?

The ability of a compound to crystallize as more than one crystalline form with different internal lattices is known as polymorphism.

What is the Noyes Whitney Equation?

Noyes Whitney equation is used to describe the dissolution rate of a drug.

What is the LADMER System?

LADMER has great importance during drug development and is  as follow,

  • L=Drug libration
  • A=Absorption
  • D=Distribution
  • M=Metabolism
  • E=Excretion
  • R=Drug Therapeutic Response

What is Absorption?

The amount of unchanged drug which reaches the general circulation is known as absorption.

What are the mechanisms for Drug absorption?

Drugs may be absorbed by following

  • Passive Diffusion
  • Active Transport
  • Carrier Mediated Transport
  • Facilitated Diffusion
  • Carrier mediated intestinal Transport
  • Vesicular Transport

What is the pH of GIT?

pH of different parts of GIT is as follow,

Oral Cavity

pH of the oral cavity is 7.0


pH of the esophagus is 5-6.


pH of the stomach at fasting stage is 2-6

and during the feed stage it is 1.5-2.0


pH of duodenum is 6-6.5


pH of jejunum is 6.5-7.0


pH of the ileum is 7.0


pH of Colon is 5.5-7.0


pH of the rectum is 7.0

What is Shunting?

The process in which a drug enters into body fluid (other than blood) before or after entering into systemic circulation.


  • Example of shunting is secretion of drug from blood into parotid.
  • Liver sometimes secrete drugs from blood into bile.

Drug Distribution

The reversible transfer of drug between blood and extravascular fluids and tissues is known as distribution.

What is drug Protein binding?

Drug protein binding is a process in which the drug binds reversibly to the protein molecule.

Unbound drug is required to give its effect and binding of drug with proteins reduces the elimination rate.

As we know proteins consist of amino acids so type and position of amino acid in protein molecules determine the binding of drug to the protein.

Composition of Blood plasma.

Human blood plasma consists of 93% of water and 7 % consist of different types of dissolved compounds mainly proteins.The major protein found is albumin.

What is the Molecular Weight Of Human Albumin?

Molecular weight of human albumin is approximately 67500 daltons.

Human albumin consists of how many amino acids?

Human albumin consists of 20 different amino acids.

Name the amino acids which binds with acidic drugs

Following are the amino acids which have basic groups and with which acidic drugs bind,

  • Arginine
  • Histidine
  • Lysine

Also Read

Reverse Osmosis water purification system.

Name the amino acids which bind with Basic drugs?

Following are the amino acids which have acidic groups and with which basic drugs are bind,

  • Aspartic acid
  • Glutamic acid
  • Tyrosine

What is Biotransformation (Metabolism)

Metabolism or biotransformation is defined as 

The process in which a drug is chemically converted into other compounds in the body is known as metabolism.

What is the first Pass Effect?

Drugs absorbed from GIT first go to the liver before entering into systemic circulation and in liver biotransformation or metabolism of drugs occur and this process is known as first pass effect.

Due to the first pass effect the systemic availability of drugs is reduced and bioavailability is also reduced.


The removal of drugs from the body is known as excretion.

Which are drug excretion routes?

Drug from body may be excreted by following,

  • Excretion through kidney
  • Excretion through Bile
  • Excretion through Saliva
  • Excretion through Lungs
  • Excretion through Milk 
  • Excretion through Sweat
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