The useful and toxic effects of many plants and animals products were known to man since ancient times. Infact, there has been a quest for drugs and remedies since the existence of mankind itself.
In early days, there was a close relationship between religion and the treatment of disease. The knowledge of the use of drugs often tested with the priest or holymen. Drugs water thing to be magical in their actions several cultures like the Chinese, Greek, Indian, Roman, Persian, European and many others contributed a great deal to the development of medicine in early times. The drug prescription included preparations from herbs, plants, animals and minerals. However, written information on remedies used in early times is lacking.
The Indian and the Chinese writings are amongst the oldest written material in medicine. India’s earliest pharmacological writing are from the ‘Vedas’. Rigveda (3000 BC) has description of some medicines. An ancient Indian physicians charaka, and then, sushruta and Vagbhata, described many herbal preparations included in “Ayurveda” (meaning the science of life). Indian practiced vaccination as early as 550 BC.
“Pen Tsao” the Chinese meteria medica was written as early as 1700 BC and it contained classification of medicinal plants and some preparations of plants, animals, and metals.
In the middle ages many herbal gardens were cultivated by the monasteries. Paracelsus the “grand father of pharmacology” born in Switzerland was the son of a physician. He opined that complicated mixture of drugs should not be used and also wrote,”all drugs are poisonous- it is only the dose which makes a thing a poison”. This statement holds good even today.
Through medicine developed simultaneously In several countries, the spread of knowledge was limited because of poorly developed Communication across the world. By the Beginning of the first century, it was realized That there was a need to standardize the Method of obtaining uniform medical preparations.
James Gregory (1735-1821 AD) recommended certain dangerous measures like blood letting, use of emetics and purgatives in the treatment of disease-such measures were often fatal. He meant to induce other suffering to relieve pain/suffering and this was probably the basics of word ‘allopathy’ meaning ‘the other suffering’. This word still being used for the modern system of medicine is a misnomer. Homeopathy meanings ‘similar suffering’ was introduced by Samuel Hahnemann. The principles of this system include “like cures like” and “dilution enhances the potency of drugs”. Various traditional system of medicine were practiced in different parts of the world like homeopathy, ayurved, unani, siddha system and allopathy.
Thus several systems of medicine were introduced of which only a few survived. The basic reason for the failure of these systems is that man’s concept about disease were incorrect and baseless in those days. By the end of the 17th century the importance of experimentation, observation and scientific methods of study become clear. Francois Magendie and Claude Bernard popularized the year is animal experiments to understand the effects of drugs. Simultaneous development of other branches of science viz botany, zoology, chemistry and physiology helped in the better understanding of pharmacology.
By the 19th century, methods for isolation of drugs were developed. Rudolph Bucheim (1820-1879) set up the first laboratory in his home at Dorpat Estonia in 1847 exclusively ment for research on drugs. Oswald Schmiedeberg (1838-1891) a student of Bucheim, conducted extensive research in drugs, trained 120 students and wrote a medical textbook. He has been called “Father of Pharmacology” for his contribution and the most prominent pharmacologist of the 19th century.
The last century had seen rapidly growth of the subjects with several new drugs, new concepts and techniques being introduced. We now know much more about receptors and molecular mechanism of action of many drugs. Several disease, which were considered incurable and fatal, can now be completely cured with just a few tablets.
Evidence-based medicine: with the growth of science and the development of scientific methods of research, treatment of disease, now relies largely on evidence-based medicine. Rigorous steps are followed and care is exercised in the introduction of new drugs. Well designed multicentric trials involving a fair number of participants are required to prove the safety and benefits of a drugs in a given condition before a drug can be used in general population. The modern system is thus evidence-based medicine.
In the Absorption & Distribution process, a drug has to move across various biological membranes like cell wall, blood-brain barrier etc. the biological membrane is made up of 2 layers of phospholipids with intermingled protein molecules. All Lipid-Soluble substances get dissolved in cell membrane & they are easily permeated into the cells.
The success of antibacterial agents owes much to the fact that they can act selectively against bacterial cells rather than animal cells. This is largely because bacterial and animal cells differ both in their structure and in their biosynthetic pathways. Let us consider some of the differences between the bacterial cell (defined as prokaryotic ) […]