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Screening of antipyretic drugs

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screening methods for new antipyretic drugs

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Screening of antipyretic drugs

  1. 1. SCREENING OF ANTIPYRETIC DRUGS: • PRESENTED BY :SINDHOORA D FIRST MPHARM DEPT.OF.PHARMACOLOGY SCP,MANGALORE 1
  2. 2. SCREENING OF ANTIPYRETIC DRUGS CONTENT: • Introduction to antipyretic drugs • Screening models  Antipyretic activity in rabbits  Antipyretic activity in rats 2
  3. 3. The drugs which lowers the elevated body temperature to the normal . Drugs used are : • Aspirin • paracetamol ANTIPYRETIC DRUGS: 3
  4. 4. Mechanism of action : • Antipyretic drugs resets the thermostat toward normal and rapidly lowers the body temp of febrile patients by increasing heat dissipation as a result of peripheral vasodilation and sweating • Inactivation of COX enzyme. 4
  5. 5. Screening models : • Brewer’s yeast suspension method Antipyretic activity in rabbits Antipyretic activity in rats 5
  6. 6. Brewer’s yeast suspension method: • Taken rats avg wt (150 -200 gm) • Body temperature by rectal thermometer • 15% brewer’s yeast+0.9% saline sol inject rat subcutaneously &placed for 18 hr • When body temperature rises test drug is given • Record the response at 30,60,120,180min 6
  7. 7. Evaluation: • A decrease of body temperature for at least 0.5°C for more than 30 min as compared with the temperature value before administration of the test compound is regarded as positive effect. 7
  8. 8. Antipyretic activity of Bauhnia Racemosa Lam. in rat • The plant Bauhinia racemosa Lam. Belongs to the “Caesalpiniaceae” Family. It is popularly known as “Apta” in Marathi, “Kanchnal” in Hindi. Dhar et al, (1968) reported the antipyretic activity in mice from the hydro alcoholic extracts of Bauhinia racemosa. 8
  9. 9. • Thirty six healthy Wistar Albino rats of 200- 250gms were divided into six groups of six animals each, with 50% sex ratio. • The initial rectal temperature of each animal was recorded by digital thermometer and its hourly variation was noted for 3 and their average was recorded • The pyrexia was induced by injecting a suspension of 15% of brewer’s yeast and 2% gum acacia in normal saline sub-cutaneously below the nape of neck in the volume of 1ml/100gm of animal weight. 9
  10. 10. • The aqueous extract was given orally to group 1& 2 of 100,200mgkg • The alcoholic extract was given orally to group 3& 4 of 100,200mgkg • The 5 group is given with paracetamol of 100,200mgkg • Sixth group is given with saline sol of 0.5 ml serve as negative control. • Rectal temperature was recorded at 1,2&3 hour. • The difference in temperature between 0 hour and at the end of 3 hr it is compared 10
  11. 11. • Aqueous and alcoholic extracts of Bauhinia racemosa Lam. produced significant antipyretic activity in rats, which was induced by brewer’s yeast. The temperature was brought back to normal after 4 hrs of post administration of extracts. The aqueous extract @200mg/kg body weight and alcoholic extract @100mg/kg and 200mg/kg body weight was found to have significant effect and was found significant at 5% level of significance 11
  12. 12. Group Temp of Apyretic rats Temp of Pyretic rats Average Temp After drug administration 1Hr 2Hr 3Hr 1Hr 2Hr 3Hr T1 98.8±0.210 98.2±0.502 98.51±0.422 101.48±0.465 101.81±0.360 101.86±0.212 101.86 ±0.280 101.91±0.267 T2 98.53±0.174 98.48±0.535 97.98±0.445 101.51±0.263 100.51±0.339 99.45 ±0.292 99.76±0.254** 99.33±0.130 T3 98.7±0.271 97.9±o.425 98.23±0.325 101.58±0.195 101.21±0.336 101.23±0.189 101.36±0.172 101.27±0.232 T4 97.9±0.403 98.85±0.291 98.43±0.382 101.48±0.215 101.23±0.413 101.1±0.304 100.86±0.284 101.06±0.334* T5 98.57±0.354 98.3±0.276 98.78±0.310 101.46±0.212 100.53±0.283 100.78±0.265 100.27±0.257** 99.5±0.225 T6 98.56±0.389 98.43±0.399 98.11±0.228 101.75±0.105 101.01±0.153 100.28±0.318 100.28±0.228** 99.56±0.212 12
  13. 13. Antipyretic activity of Gracilaria Corticataj • Gracilaria corticata J.Ag. is red seaweed belonging to Rhodophyceae member shows much attention in the present study for antipyretic activity. Gracilaria corticata J.Ag. were collected from Hare island, Thoothukudi in the south east coast of Tamil Nadu. • The shade dried samples were grounded to fine powder & 3g powdered sample was packed in Soxhlet apparatus and extracted with methanol for 8 hrs. 13
  14. 14. • The excess amount of methanol was evaporated and fine methanol crude powder was prepared and stored in the refrigerator for the antipyretic activity. • Swiss albino rats were weighing (150-240 gm) and male albino rats (15-18 gm) were used. The animals were housed in the departmental animal house under standard conditions (26±2°C and relative humidity 30-35%) in 12 hours light and 12 hours dark cycle respectively for 1 week before the experiment. 14
  15. 15. The experimental treatment was carried out as; • Group I: Control group animals Normal saline 5ml/kg • Group II: Animals were treated with Paracetamol (10mg/kg) • Group III: Animals were administered with 200mg/kg methanol extract • Group IV: Animals were administered with 400mg/kg methanol extract 15
  16. 16. Antipyretic activity: • A suspension of Brewer’s yeast (15%) in saline (0.9%) was prepared. Four groups each containing 6 rats of either sex were taken. The animals were fevered by injection of brewer’s yeast suspension (10mg/kg) subcutaneously . The measurement was repeated after 30 minutes. The dose of the test compound and standard drug was given orally. • The rectal temperature was recorded again after 1, 2 and 4 hours. Paracetamol (10mg/kg) was selected as a standard drug. The various methanol extracts were dissolved in saline with the help of 2% w/v Gum acacia. 16
  17. 17. Results: • Antipyretic activity of methanol crude extract of Gracilaria corticata J.Ag. was studied by determining the effect on yeast-induced pyrexia in albino rats. • The result expressed that methanol extract of different doses caused lowering of the body temperature up to 4h following its administration. • The effect of methanol extract on yeast-induced pyrexia showed that the rectal temperature was markedly elevated to 41.7°C, after 18h the subcutaneous injection of yeast suspension decreased to 40.7°C within 1h of 200mg/kg methanol extract of Gracilaria corticata J.Ag. treatment followed by 39.6°C at 2h and further reduced to 38.2°C at 4h showing a considerable decrease in compared to paracetamol 17
  18. 18. • 400mg/kg methanol extract also showed the decreased in temperature from 41.4°C to 39.6°C after 1h of treating with the administration of the methanol crude extract of Gracilaria corticata J.Ag. • When the time was increased up to 4hr,the results were observed significant reduced temperature to 37.2°C. 18
  19. 19. • Both 200 and 400mg/kg marked antipyretic activity detected were significantly different than the controls (p<0.05). • Generally, for all concentration of methanol crude extract of Gracilaria corticata J.Ag. showed marked antipyretic activities, hence, 400mg/kg methanol extract was highly effective than 200mg/kg. • This result revealed that the methanol extract of Gracilaria corticata J.Ag. have detectable antipyretic activity as compared with standard paracetamol. 19
  20. 20. Antipyretic activity in rabbits: • Purpose and Rationale: Lipopolysaccharides from Gram-negative bacteria ,e.g. E.coli, induce fever in rabbits after i.v injection. Body weight of 150 g are used. Intial temperature is noted down. Fewered by injection of 10mlkg Brewers yeast suspension by s.c . 20
  21. 21. • The room temperature is kept at 22-24c̊. • The animals are recieve the test and standard drug by oral • The rectal temperature are recorded in 30,60,120 and 180 min post dosing 21
  22. 22. Evaluation : • The difference between the actual values and the starting values are registered for each time interval. • The maximum reduction in rectal temperature in comparison to the control group is calculated. • Results are compared with effect of the standard drug ,e.g. aminophenazone 100 mg/kg, 22
  23. 23. References • Drug Discovery and Evaluation :Pharmacological Assays, Third completely Revised Edition , by H.Gerhard Vogel • Study of Antipyretic Activity of Bauhinia racemosa lam in Rats , by V.I.Borikar, C.R Jangde, Preety Philip, D.S. Rekhe and S.K Atole. Department of Veterinary Pharmacology and Toxicology, Veterinary College, M.A.F.S.U. Nagpur Maharashtra 23
  24. 24. • Screening of antipyretic activity of Garcilaria Corticataj. AG . ,by John Peter Paul J. Research department of botany , St.Xevir’s college,Palaikottai - Tamilnadu 24

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