Aminoglycosides �

• Aminoglycosides are antibiotics which contain one or more amino sugar, glycosidic linkage and a 6 member carbon ring.
• In most instances, glucosamine is found as amino sugars.

Glucosamine

Streptidine

Streptose

Streptamine

Classification

• Mycins ( derived from Streptomyces)

Streptomycin, Kanamycin, Neomycin, Tobramycin , Paromomycin.

• Micins (derived from Micromonospora)

Gentamicin, amikacin, verdamicin.

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General properties

• All aminoglycosides are available as sulphates.
• Soluble in water.
• Strongly basic.
• Not metabolized in vivo.
• Exhibit synergism with beta lactams and vancomycin.
• Most common ADR include nephrotoxicity, ototoxicity, and neurotoxicity.

Streptomycin

• It was first aminoglycoside introduced by Waksman and his associates from Streptomyces griseus.

Chemistry

• It consists of streptidine, streptose and N- methylglucosamine rings which are linked glycosidically.
• It contains two polar and basic guanidine groups.
• It also contains weakly polar aminomethyl group.

• Physical properties
• It is available as sulphate which is white or almost white powder.
• It has slight characteristic odour.
• It is strongly basic.
• It is very soluble in water and sparangly soluble in alcohol.
• It is sensitive to moisture and high temperature.
• MP: 230°C.

• Stability and storage
• It is stored in well closed container at a temperature not exceeding 30 degree celsius.

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• Uses
• TB
• Plague (caused by Yersinia pestis)
• Streptococcal endocarditis
• Brucellosis

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Gentamicin

• Gentamicin is a complex closely related aminoglycoside obtained from Micromonospora purpurea
• Chemistry
• Purpurosamine, 2-deoxy streptamine and Garosamine are linked together via glycosidic bond.
• The molecule is basic due to the presence of amino groups at various positions.

• Physical properties
• It is available as sulfate
• It occurs as white to buff colored crystalline powder.
• It is freely soluble in water, moderately soluble in ethanol.
• It is sensitive to light, moisture and high temperature.
• MP: 218-222°C.

• Storage
• Same as Streptomycin

• Uses
• Prophylaxis of surgical infection
• Pelvic inflammatory Disease (off label)
• Prophylxis of endocarditis
• Mycobacterium infection
• Other susceptible infections (especially of gram –ve bacteria)
• Cystic fibrosis

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Macrolides

Diploma in Pharmacy

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• Macrolides are the macrocyclic lactone ring derivatives made up of 12 or more atoms.
• Macrolides contain one or more sugar generally cladinose and desosamine.
• Macrolides are products of actinomycetes (soil bacteria) or semisynthetic derivatives of them.

Cladinose

Desosamine

• Common characters of macrolides
• A large lactone ring
• A ketone group
• A glycosidically linked sugar

• List of Macrolides
• Erythromycin
• Clarithromycin
• Azithromycin
• Dirithromycin
• Oleandomycin
• Telithromycin
• Tylosin
• Spiramycin

Erythromycin

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• Chemistry
• A macrocyclic lactone ring is present consisting of 13 carbon atoms
• Ketone group is present at position 1 and 9.
• Glycosidically linked cladinose is present at position 3.
• Erythromycin largely consist of Erythromycin A, along with Erythromycin B and C.
• Methyl groups are present at 2,4,6,8,10, 12 of macrocylic ring.
• Hydroxy group is present at position 6 , 11 and 12 of the macrocyclic ring.

• Physical properties
• Erythromycin is available as Erythromycin, Erythromycin estolate, Erythromycin ethyl succinate.
• Erythromycin is bitter but its estolate and ethyl sulfate form is tasteless.
• Erythromycin occurs as white crystalline powder.
• Erythromycin is slightly soluble in water, soluble in alcohol.
• It is hygroscopic in nature. It is also sensitive to light and high temperature.
• Melting point: 135-140 degree celsius.

• Storage
• Store protected from light and moisture at temperature less than 30 degree celsius.

• Uses
• Pertusis (Whooping cough) caused by Bordetella pertusis.
• Bowel preparation for surgery in combination with Neomycin
• Non gonococcal urethritis
• Legionnaires Disease (atypical pneumonia caused by any species of Legionella bacteria)
• Lymphogranuloma venereum(LGV) caused by Chlamydia trachomatis
• Susceptible bacterial infections
• Primary syphilis
• Intestinal amoebiasis

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Azithromycin

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• Chemistry
• It is a semisynthetic derivative of Erythromycin in which N- methyl group is added between position 9 and 10.
• It contains 15 membered macrolide called azalide.
• Removal of 9-keto group coupled with incorporation of weakly basic tertiary amine increase stability to acid degradation. These changes also increase lipid solubility and subsequently half life of the drug.
• Cladinose is attached at position 3.
• Desosamine is attached at position 5.

• Physical properties (Azithromycin)
• It occurs as white or almost white crystalline powder.
• It is practically insoluble in water and in ethanol.
• It is stable under acidic condition unlike erythromycin.
• It is odorless.
• It has bitter taste.
• It is sensitive to light, moisture and high temperature.
• MP: 114°C.

• Stability and Storage
• Store protected from light and moisture at temperature less than 30 degree celsius.

• Uses
• Pharyngitis/Tonsilitis
• Community Acquired Pneumonia
• Uncomplicated gonorrhea
• Acute exacerbation of COPD.
• Uncomplicated skin/skin structure infection
• Acute otitis media
• Acute bacterial Sinusitis
• Nongonococcal or gonococcal urethritis and cervicitis
• Acute PID (Pelvic inflammatory disease)
• Cat scratch disease (caused by Bartonella hensela) (Off label)
• Genital Ulcer Disease (Chancroid) cause by bacteria bacteria Haemophilus ducrey
• Pertusis- whooping cough caused by bacterium Bordetella pertusis (Off label)
• Endocarditis (Off label)