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ANTI HYPERLIPIDEMIC AGENTS
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Dr.P.Valentina, professor, HODDepartment of pharmaceutical chemistrySRM college of pharmacy
BIOMEDICAL IMPORTANCE OF CHOLESTEROL
• High cholesterol in blood implicates cardio vascular diseases
• Atherosclerosis and coronary artery disease
H O
H
H
H
c h o l e s t e r o l
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SYNTHESIS TRANSPORT AND STORAGE
• Acetate is the main precursor(released from acetyl CoA
• Acetate converted to mevalonate
• Then mevalonate converts to squalene
• Squalene after few steps produces cholesterol
Activated isoprene units are must for cholesterol synthesis
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UNDERSTANDING
• Fats and oils are fatty acids and tri acyl glycerol• Apoprotein (free form) combines with lipid to form apo
lipoproteins.• They further synthesize lipoprotein bodies called as
chylomicrons• Chylomicrons transport into liver from chyle (lymph) where
fatty acids are converted to TAG.• Cholesteryl esters are formed in liver by ACAT. • They form VLDL and move further to other tissues• VLDL move to the extra hepatic tissue and release free fatty
acids and tri acyl glycerols. Now it becomes IDL(remnant)• Further removal of TAG produces LDL (rich in cholesterol)
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HYPER LIPIDEMIC DRUGS
• HMG Co‐A REDUCTASE INHIBITORS
1. Lovastatin ‐ t ½ = 2 hours
2. Fluvastatin
3. Simvastatin
4. Atorvastatin
5. Pitavastatin
6. Rosuvastatin
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FIBRIC ACID DERIVATIVES
1. Clofibrate t ½ = 12 hours
2. Gemfibrozil
3. Benzafibrate t ½ = 2 hours
4. Micronized fenofibrate
5. Ciprofibrate
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BILE ACID SEQUESTRANTS
1. Cholestyramine
2. Colestipol
3. Colesevelam
4. Ezetimibe
5. Ezetimibe + simvastatin
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NICOTINIC ACID DERIVATIVES
1. NIACIN 2. NIACIN + LOVASTATIN
MISCELLANEOUS DRUGS
1. Probucol2. Tamoxifen3. Ratoxifene
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HMG Co‐A REDUCTASE INHIBITORS
• STATINS ARE REGARDED AS BLOCKBUSTERS IN CHOLESTEROL THERAPY
• STATINS ARE STRUCTURALLY SIMILAR TO HMG Co‐A
• THEY ACT AS COMPETITIVE INHIBITORS FOR HMG Co‐A REDUCTASE
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2‐METHYL BUTANOIC ACID ‐1,2,3,7,8,8a‐ HEXA HYDRO 3,7 DIMETHYL ‐8‐[2‐(TETRAHYDRO 4 – HYDROXY‐6‐OXO‐2H‐PYRAN‐2‐YL)ETHYL]‐1‐NAPTHALENYL ESTER
O H2CH2C
O
O
OH
C
OH2C
H2CH3C
H3C
CH3
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• OBTAINED FROM FERMENTATION OF ASPERGILLUS TERRERS AND MONASCUS PURPUREUS
• THEY REDUCE LDL CHOLESTEROL
• LOVASTATIN 80 mg reduces 40% of LDL
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SYNTHESIS
HO Cl
para chloro phenol
Oa c e t o n e
C l
C l
C l
c h l o r o f o r m
Sodium chloride/acid reflux
Cl O
C CH3
H3C
COOH
Clofibric acid18
BENZAFIBRATE
Cl CO NH CH2
H2C
OC
CH3
CH3
COOH
2‐{p‐[2‐(p‐chlorobenzamido)ethyl]phenoxy}‐2‐methyl propanoic acid
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SYNTHESIS
O
C l
C l
c h l o r o b e n z o y l c h lo r i d e
HO CH2
H2CNH2
N
‐HCl
C l C O N H C H 2
H 2 C
O H
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Cl CO NH CH2
H2C O
C
O
C6H5
CONDENSATION
KOH HYDROLYSIS
DRUG
Cl CO NH CH 2
CH 2
O
C
CH 3
H 3C COO
C 2H 5
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MISCELLANEOUS DRUGS
• PROBUCOL
C
C
HO
S C
CH3
CH3
S
C
OH
C
H3C
CH3
CH3
H3C CH3
CH3
CH3
H3C
CH3
H3C CH3
CH3
4,4 [(1‐methyl ethylidene)bis (thio) bis [2,6 bis (1,1 dimethyl ethyl ) phenol 24
STRUCTURAL ACTIVITY RELATIONSHIP
• Statins exploit conformational flexibility of enzyme HMG Co‐A to create a hydrophobic pocket near the active site for hydrophobic ring system of inhibitor thus occupies both HMG binding pocket and Co‐A pocket
• Lactonic group is essential for activity. This biotransforms into open carboxylic acid
• Synthetic statins contain 4‐ fluoro phenyl moieties
• Atorvastatin contains polar side chains that form hydrogen bonding to Ser 565
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SAR OF FIBRATES
• Fibrate contain common fibrate head which is necessary for action.
R
OCH2
CO
OH
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CONCLUSION
• STATINS ARE STILL THE BEST SOURCE FOR LOWERING CHOLESTEROL IN BLOOD
• STATINS IN COMBINATION WITH NIACIN IS THE PERFECT CHOICE FOR MAINTAINING CHOLESTEROL LEVELS
• FIBRATES ARE REDUCED IN USE DUE TO RHABDOMYLOMA
• MISCELLANEOUS DRUGS ARE GIVEN WHENEVER NECESSARY
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REFERENCES
• BURGER’S MEDICINAL CHEMISTRY AND DRUG DISCOVERY VOL‐3 ; 343
• STATINS – BURGER’S MEDICINAL CHEMISTRY AND DRUG DISCOVERY VOL‐3 ; 345
• SYNTHETIC PART – MEDICINAL CHEMISTRY VOL‐2 BY K. ILANGO AND P. VALENTINA; 278
• ILLUSTRATION REFERENCE – BURGER’S MEDICINAL CHEMISTRY VOL‐3 ; Fig 7.1 ; 359
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