John K Smith and his brother-in-law, John Gilbert, opened a drugstore in Philadelphia in 1830.

When John Gilbert decided to withdraw, Smith was joined by his younger brother George. The company soon became a leader in drug wholesaling.

 Thomas Beecham was the founder of the Beecham organisation. Born in Oxfordshire, England, in 1820, the son of a farm labourer, he enjoyed only a brief formal education before starting work at the age of eight, as a shepherd boy.

He noticed that sheep tend to eat certain grasses and started to experiment with and study these herbs, recognising their medicinal properties.

Having decided that his future was as a full-time medicine vendor, Beecham moved to the town of Wigan in the north of England. He graduated from working as a market stallholder to owning a shop, and as sales of Beecham's Pills brand of laxative grew, he began to concentrate on manufacturing and national marketing.

Beecham closed his shop in Wigan and moved to St Helens, another industrial town a few miles away, where he opened the first Beecham factory.

It was here that Beecham devised mechanised production methods, a necessary move because his markets were now as far afield as Africa and Australia.

Mahlon Kline joined Smith & Shoemaker, as John K Smith & Co had become, as a 19-year-old bookkeeper.

He was too keen and ambitious to confine himself to bookkeeping for long and sought additional duties in the firm. He eventually asked to become a salesman and within a few years his efforts resulted in the addition of many new and large accounts.

Anxious for information about all aspects of the business, Kline conscientiously acquired a scientific knowledge of drugs and medicines by attending courses at the Philadelphia College of Pharmacy.

Early research and development by Burroughs Wellcome was centered on the Wellcome Medical Research Laboratories and the Wellcome Physiological Research Laboratories, both founded in the 1890s.

Henry Wellcome's tenet of "Freedom of research - Liberty to publish" attracted many leading scientists to the London facilities.

A centre for investigation into tropical diseases was added in 1901. This was based in Khartoum in the Sudan, and featured a floating laboratory on the River Nile that enabled research and medical teams to reach regions that were not otherwise easily accessible.

The Wellcome Tropical Research Laboratories were formally opened in 1902.

Wellcome's US subsidiary was opened in New York in 1906 and manufacturing and research facilities followed.

Research in the 1920s included studies of the primary and secondary immune responses, production of insulin, the introduction of new forms of diphtheria vaccines and the development of a yellow fever vaccine.

Efforts also were directed to the development of good manufacturing facilities and practices.

In 1924, The Wellcome Foundation Ltd was registered in London as a private company to coordinate Wellcome's expanding businesses and research activities.

The 1930s brought further success. Digoxin was isolated from the digitalis leaf to become the standard treatment for congestive heart failure, a globin zinc insulin was developed, and the first pure curare alkaloid was produced.

Sir Henry Wellcome died in 1936 at the age of 82, leaving, through his will, the creation of the Wellcome Trust, a charitable foundation to support medical research worldwide.

During the 1950s, Smith Kline and French launched Thorazine (chlorpromazine), which revolutionised the treatment of mental illness.

It became the product of reference in the first generation of central nervous system drugs. However, in the beginning, there were some difficulties.

One was the fact that American private practice psychiatrists did not at first accept the idea of treating mentally ill patients by chemical means. But Smith Kline and French's hypothesis that the drug actually corrected mental malfunctioning was vindicated in several clinical trials, which were reported later in American medical journals.

Soon afterwards, Thorazine began to be used increasingly in mental health programmes. It won the status of a "fundamental drug in medicine," the standard against which all other tranquillisers were measured.

As early as 1945, researchers at Smith Kline and French began evaluating the therapeutic advantages of coatings for tablets.

Chemists also started searching for chemical or mechanical techniques that would gradually release drugs for a predictable therapeutic effect over an entire day or night.

By 1949, Donald McDonnell realised the possible solution to the release-action puzzle, which was to fill capsules with pellets coated with medication that would dissolve at different times.

Because of the complexities of implementation and adaptation to large-scale manufacturing, it was not until 1952 that the time-released capsule known as a Spansule was used and marketed.

It was first used for Dexedrine (dextroamphetamine sulfate) for treating psychiatric patients of certain types and patients suffering from depression, fatigue or listlessness, and for patients afflicted with narcolepsy.

The Spansule provided a novel form of drug delivery, which was a major therapeutic breakthrough. It quickly released the required initial dose and then slowly and gradually released many extremely small doses to maintain a therapeutic level lasting from 10 to 12 hours, providing all-day or all-night therapy with one dose.

Subsequently, the firm marketed a number of other sustained-release preparations, one of which is the cold remedy Contac. Launched in 1960, Contac later became the world's leading cold remedy.

More than seven years of research and more than 35,000 hours of work were required to develop the sustained-release capsule, Spansule.

GlaxoSmithKline is formed through the merger of Glaxo Wellcome and SmithKline Beecham.

Avandia passes one million retail prescriptions in the US.

GSK makes a ground-breaking pledge to provide three HIV/AIDS medicines to developing country governments at significant price reductions.

GSK moves to its new UK headquarters in Brentford, West London. GSK House consists of four, five-storey buildings and a 16-storey tower block linked by an internal fully-glazed 'street'. The building was designed with input from employees.

Twinrix, the first combination vaccine to prevent hepatitis A and B is approved by the FDA.

GSK reorganises its research and development efforts into Centres of Excellence for Drug Development (CEDDs), small business units that emphasise flexibility, innovation and therapeutic focus.

GSK launches Advair, an anti-asthma medicine, in the US and acquires the Sensodyne range of oral care products.

GSK launches the African Malaria Partnership to help combat a disease that kills more than one million people every year.