Concept of generics Pharmaceutical Regulatory Science Notes

A generic drug is a medication created to be the same as an already marketed brand-name drug in dosage form, safety, strength, route of administration, quality, performance characteristics, and intended use. These similarities help to demonstrate bioequivalence, which means that a generic medicine works in the same way and provides the same clinical benefit as the brand-name medicine. In other words, you can take a generic medicine as an equal substitute for its brand-name counterpart.

Any generic medicine must perform the same in the body as the brand-name medicine. It must be the same as a brand-name medicine in dosage,  form and route of administration, safety, effectiveness, strength, and labeling (with certain limited exceptions).  It must also meet the same high standards of quality and manufacturing as the brand-name product, and it must be and quality, taken and used in the same way as well. This standard applies to all generic medicines.
Generic medicines use the same active ingredients as brand-name medicines and work the same way, so they have the same risks and benefits as the brand-name medicines. The FDA Generic Drugs Program conducts a rigorous review to ensure generic medicines meet these standards, in addition to conducting inspections of manufacturing plants and monitoring drug safety after the generic medicine has been approved and brought to market.
A generic drug may have certain minor differences from the brand-name product, such as different inactive ingredients. 
It is important to note that there will always be a slight, but not medically significant, level of expected variability—just as there is for one batch of brand-name medicine compared with the next batch of brand-name product. This variability can and does occur during manufacturing, for both brand-name and generic medicines. When a medicine, generic or brand-name, is mass-produced, very small variations in purity, size, strength, and other parameters are permitted. FDA limits how much variability is acceptable.

Generic drugs are approved only after a rigorous review by FDA and after a set period of time that the brand product has been on the market exclusively. This is because new drugs, like other new products, are usually protected by patents that prohibit others from making and selling copies of the same drug.  
Generic drugs tend to cost less than their brand-name counterparts because generic drug applicants do not have to repeat animal and clinical (human) studies that were required of the brand-name medicines to demonstrate safety and effectiveness. This abbreviated pathway is why the application is called an “abbreviated new drug application.” 

Generic pharmaceutical manufacturers must prove to the FDA that their version of a drug:
contains the same active ingredient;
is identical in strength,
dosage form, and route of administration;
has the same indications, dosing, and labeling; 
provides the same efficacy and safety profile to patients (“bioequivalent”)

The Indian government began encouraging more drug manufacturing by Indian companies in the early 1960s, and with the Patents Act in 1970. The Patents Act removed composition patents for foods and drugs, and though it kept process patents, these were shortened to a period of five to seven years. The resulting lack of patent protection created a niche in both the Indian and global markets that Indian companies filled by reverse-engineering new processes for manufacturing low-cost drugs. The code of ethics issued by the Medical Council of India in 2002 calls for physicians to prescribe drugs by their generic names only. India is a leading country in the world’s generic drugs market, with Sun Pharmaceuticals being the largest pharmaceutical company in India. Indian generics companies exported US$17.3 billion worth of drugs in 2017–18 (April–March) year.
In 1945–2017, bioequivalence studies were only required for generics of drugs that are less than four years old. Since 2017, all generic drugs of certain classes, irrespective of age, require bioequivalence to be approved