PRINCIPLES OF ORGANIC MEDICINAL CHEMISTRY have been discovered from a variety of soil fungi and some hacteria these drugs form the most important group of chemotherapeutic agents used against infective diseases. Ex.:Penicillin,Streptomycin,Tetracycline. (d)Minerals.Minerals or mineral-containing medicated springs have been in use sinc time immemorial.Several such hot water springs with medicinal value in India.Ex.:Raigrin(Bihar),Sahashradhara (Dehradun).Minerals of medicinal value are iron,calcium,magnesium,aluminium,sodium,potassium etc. C.Semi i-synthetic.In some ca expensive me time tral sources may be impurs.In there cages semiaynthetie preses are ue ones Ex.6-Aminopenicillanic acid is obtained from the fungus Penicillium chrysogenum. D.Biosynthetic.Several drugs are complex polypeptides.It is difficult to obtain these drugs in pure form from natural sources and are very expensive to synthesize in the labora- tory. Ex:Biosynthetic human insulin,interferon,erythropoietin,hepatitis vaccine Amongst all these,synthetic drugs are used most widely because of their inexpensive- ness,ease of quality control,mass production and therapeutic efficacy.The synthetic drugs are prepared by chemical processes. Ex:Chloroquine,acetylsalicylic acid,chlorpromazine,ephedrine etc. 2.By Action 他 g effe ets:Ex d atropine both increase heart the mouth.Thus,marijuana wou be clas tied as atropine-lik 3.By therapeutic use These drugs mainly affect the normal dynamic processes of the body.They are: (i)Anti-arrhythmies (ii)Antianginals (Vasodialator (i)Anti-hypertensives ()Card (vi)Hypocholesteric agents (vii)Antiallergic agents (viii)Drugs acting on GIT (ix)Drugs influence renal function (r)Drugs acting on central nervous system (xi)Drugs acting on peripheral nervous system 4.By site of drug action Ex:Alcohol is a depressant drug because of its depresa ant CNS action.This system is sstimulant cocaine also (pain re 4 PRINCIPLES OF ORGANIC MEDICINAL CHEMISTRY C-8—N-CHEMI\CHE2-1.PM5 have been discovered from a variety of soil fungi and some bacteria. These drugs form the most important group of chemotherapeutic agents used against infective diseases. Ex. : Penicillin, Streptomycin, Tetracycline. (d) Minerals. Minerals or mineral-containing medicated springs have been in use since time immemorial. Several such hot water springs with medicinal value are popular in India. Ex. : Rajgrin (Bihar), Sahashradhara (Dehradun). Minerals of medicinal value are iron, calcium, magnesium, aluminium, sodium, potassium etc. C. Semi-synthetic. In some cases, especially with complex molecules, the synthesis of a drug may be very difficult or expensive and uneconomical. At the same time, the ones de￾rived from natural sources may be impure. In these cases semisynthetic processes are used. Ex. : 6-Aminopenicillanic acid is obtained from the fungus Penicillium chrysogenum. D. Biosynthetic. Several drugs are complex polypeptides. It is difficult to obtain these drugs in pure form from natural sources and are very expensive to synthesize in the labora￾tory. Ex: Biosynthetic human insulin, interferon, erythropoietin, hepatitis vaccine. Amongst all these, synthetic drugs are used most widely because of their inexpensive￾ness, ease of quality control, mass production and therapeutic efficacy. The synthetic drugs are prepared by chemical processes. Ex: Chloroquine, acetylsalicylic acid, chlorpromazine, ephedrine etc. 2. By Action According to similarity of drug effects: Ex: marijuana and atropine both increase heart rate and cause dryness of the mouth. Thus, marijuana would be classified as atropine-like drug. 3. By therapeutic use These drugs mainly affect the normal dynamic processes of the body. They are; (i) Anti-arrhythmics (ii) Antianginals (iii) Vasodialators (iv) Anti-hypertensives (v) Cardiotonics (vi) Hypocholesteric agents (vii) Antiallergic agents (viii) Drugs acting on GIT (ix) Drugs influence renal function (x) Drugs acting on central nervous system (xi) Drugs acting on peripheral nervous system 4. By site of drug action Ex: Alcohol is a depressant drug because of its depresant CNS action. This system is limited when a drug has an effect at several body sites (e.g., the CNS stimulant cocaine also has local anesthetic (pain reducing) effects