Tetracyclines
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Tetracyclines

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Tetracyclines Tetracyclines Presentation Transcript

  • TETRACYCLINES Presented by T.SHIVAKUMARKOTTAM INSTITUTE OF PHARMACY
  • CHEMICAL STRUCTURE OFTETRACYCLINE:
  • NOMENCLATURESystematic (IUPAC) name(4S,6S,12aS)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a- octahydro-3,6,10,12,12a-pentahydroxy-6-methyl-1,11- dioxonaphthacene-2-carboxamide OR(4S,6S,12aS)-4-(dimethylamino)-3,6,10,12,12a-pentahydroxy-6- methyl-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2- carboxamide
  • CHEMICALNAMEChemical Name: A variably hydrated form of (4S,4aS,5aS,6S,12aS)-4-Dimethylamino- 1,4,4a,5,5a,6,11,12a-octahydro-3,6,10,12,12a- pentahydroxy-6-methyl-1,11-dioxonaphthacene-2- CarboxamideMolecular Formula: C22H24N2O8
  • Physical PropertiesCOLOUR: yellow crystalline powder.SOLUBOLITY: Very slightly soluble in water; soluble in alcohol and in methyl alcohol;sparingly soluble in acetone. It dissolves in dilute acid and alkaline solutions.. It loses not more than13% of its weight on drying.
  • Chemical propertiesThe reactions that tetracyclinesundergo are generally of asophisticated nature, dictated by thecomplex functionality and thesensitivity of the molecules to mildreaction conditions (acid, base, heat) .
  • Acidic conditions The conjugated triones system extending from C1 to C3 of ring A is acidic in nature with PKa1=2.8 to 3.4. When exposed to dilute acid conditions, tetracycline undergoes dehydration to yield anhydrotetracycline. Anhydroterramycin suffers further cleavage and lactonization to apoterramycin:Diluted acid promotes epimerization at C-4 as well.
  • Basic conditions C4 atom and its substitute exhibits PKa2ranging from 9.1 to 9.7 which representsstrong alkaline natureMild alkali attacks 11a carbon oftetracycline, which is transformed toisotetracycline
  • The reasons for ammphoteric nature of tetracyclines is their complex structure with three structural units representing three PKa values. The conjugate phenolic enone system from C10 to C12 is associated with weak basic PKa values ranging from 7.2 to 7.8.
  • Because of the amphoteric nature, tetracyclines are capable of forming water-sluble salts with strong acids such as hydrochloric acid and strong bases such as sodium hydroxide and potassium hydroxide.And water insoluble salts of tetracyclines are formed with divalent and polyvalent metals
  • INCOMPATIBILITY: Chelation with metals: among the chemical and clinical properties of tetracyclins, chelation with ions is an important feature.Tetracyclins are able to form complexes with divalent and trivalent metal ions such as Fe3+, Fe2+, Cu2+, Ni2+, Co2+, Zn2+, Mn2+, Mg2+, Ca2+, Be2+, Al3+ and with salicilates, phosphates,citrates,polyvinylprrolidine,t hiourea,lipoproteins,serum albumin,globulin and RNA.
  • These salts of metal ions are insoluble in water atneutral conditions and cause inconvenience in theprepararion of solutions and also produceunfavourable blood titres of tetracyclines, within thebody
  • STBILITY :EPIMERISATION: One of the important property of tetracycline is their ability to undergo epimerization at C4 position and the isomers are referred to as epitetracyclines.
  • CLASSIFICTION OF TETRACYCLINS :According to source:Naturally occurringTETRACYCLINECHLORTETRACYCLINEOXYTETRACYCLINEDEMOCYCLINE
  • Semi-synthetic Doxycycline Lymecycline Meclocycline Methacycline MinocyclineRolitetracycline
  • According to duration ofaction:Short-acting (Half-life is 6-8 hrs) Tetracycline Chlortetracycline Oxytetracycline
  • Intermediate-acting (Half-life is ~12 hrs) 1.Demeclocycline 2.Methacycline Long-acting (Half-life is 16 hrs or more) 1.Doxycycline 2.Minocycline 3. Tigecycline
  • REFERENCESBurden, V. (1991). Purification and characterizationof tet(M), a protein that renders ribosomes resistantto tetracycline. Journal of Biological Chemistry 266,2872-7 .Chaudhary, I., Wirth, M., Rosen, R., Nicolau, G. & Yacobi, A. (1993). Metabolism of DMGDMDOTa novel antibiotic in laboratory animals, in vitro/in vivo correlations.Chopra, I., Hawkey, P. M. & Hinton, M. (1992). Tetracyclines, molecular and clinical aspects.Journal of Antimicrobial Chemotherapy 29,245-77.Eliopoulos, G. M., Wennersten, C. B., Cole, G.& Moellering, R. C. (1994). In vitro activities of
  • Thank you….T.SHIVASHIVA.PHARMACIST@GMAIL.COM