AmpicillinTendai Bere

Washington Dendera

Tanyaradzwa Ngara

Nyasha Mudukuti

Antibiotics

• are specific chemical substances derived from orproduced by living organisms that are capable ofinhibiting the life processes of other organisms.

Penicillins

• a group of closely related antibiotics used to treat awide variety of bacterial infections occurring in thebody

• The first antibiotic was discovered in 1896 by ErnestDuchesne and "rediscovered" byAlexander Flemmingin 1928 from the filamentous fungus Peniciliumnotatum.

• The antibiotic substance, named penicillin, was notpurified until the 1940s (by Florey and Chain), just intime to be used at the end of the second world war

• Penicillin was the first important commercial productproduced by an aerobic, submerged fermentation

Antibiotics can be selectively toxic by targeting such features as the bacterial cell wall, 70S ribosomes, and enzymes that are specific to bacteria.

In this way the human eukaryotic cells are unaffected.

• The walls of bacteria are made of a complexpolymeric material called peptidoglycan.

• It contains both amino acids and amino sugars.

• The amino sugars are of two kinds N-acetylglucosamine (NAG) and N-acetylmuramic acid(NAM

-The beta-lactams all work by interfering with the synthesis of the bacterial cell wall by: 1) disruption of mucopeptide synthesis

2)Penicillin can cause rapid lysis of the bacterial cell by inducing the action of bacterial autolysins (mucopeptidehydrolases).

3) penicillin exposes the cell to osmotic action and water passes from the hypotonic external environment into the interior of the cell.

Ampicillin prodrug is Broad - spectrum penicillin usedagainst gram +ve and gram –ve bacteria

- ampicillin is more active against enterococci, Listeriamonocytogenes, and beta-Iactamase negativeHaemophilus influenzae

Two types:

• Biosynthetic penicillin is natural penicillin that isharvested from the mould itself through fermentation

• Semi-synthetic derivatives of penicillin - likeAmpicillin, Penicillin V

• consist of the basic Penicillin structure, but have beenpurposefully modified chemically by removing theacyl group to leave 6-aminopenicillanic acid and thenadding acyl groups that produce new properties

• Antibiotics are produced on an industrial scale usinga variety of fungi and bacteria

• Penicillin is produced by the fungus Penicilliumchrysogenum

• penicillin is a secondary metabolite, so is onlyproduced in the stationary phase.

• It requires a batch fermenter, and a fed batch processis normally used to prolong the stationary period andso increase production.

• optimum temperature – 25 -27ºC

• Fermentation process is aerobic

• volume fermenter is 40 –200 dm3

• The first strain used to produce penicillin was Penicillin notatum, which produced1 mg dm‐3

• Today, using a different species (P. chrysogenum) and a better extraction procedures the yield is 50 g dm‐3.

• Downstream processing is relatively easy sincepenicillin is secreted into the medium (to kill othercells), so there is no need to break open the fungalcells.

• However, the product needs to be very pure, since itbeing used as a therapeutic medical drug, so it isdissolved and then precipitated as a potassium salt toseparate it from other substances in the medium.

• The resulting penicillin (called penicillin G) can bechemically and enzymaticallymodified to make avariety of penicillinswith slightly different properties.

• These semi‐synthetic penicillinsinclude penicillin V,penicillin O, ampicillinand amoxycillin.

• Semi-synthetic derivative of penicillin

• consist of the basic Penicillin structure, but has beenpurposefully modified chemically by removing theacyl group to leave 6-aminopenicillanic acid and thenadding an acyl group (amino group)

• allows the ampicillin to be effective against gramnegative organisms as well as the gram positiveorganisms covered by penicillin

• makes ampicillin better as a 'broad spectrumantibiotic'

Fig2: Structure of Penicillin, Where “R” is the variablegroup

Fig 3: Structure of Ampicillin, with the added aminogroup

• the product needs to be very pure, since it being usedas a therapeutic medical drug, so it is dissolved andthen precipitated as a potassium salt to separate itfrom other substances in the medium

• It is sold in liquid form, packaged into vials, for readyto use by injection

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