Amoxicillin is a broad spectrum, semi-synthetic antibiotic used to treat bacterial infections in poultry. It exists as a trihydrate compound containing amoxicillin and inhibits bacterial cell wall synthesis. Amoxicillin is well absorbed orally and distributed throughout the body, achieving high concentrations in tissues. It is effective against a wide range of gram-positive and gram-negative bacteria commonly affecting poultry. The standard dosage for poultry is 20mg/kg daily for 3-5 days by dissolving in drinking water over a few hours.
2. Composition
› Each 100gm contains:
– Amoxycillin trihydrate: 46gm equivalent to amoxicillin base 40gm
3. Amoxicillin
› Amoxycillin
– Semi synthetic antibiotic, an analog of ampicillin.
– Broad spectrum of bactericidal activity.
› Amoxycillin forms
– There are various hydrated forms of amoxicillin, including monohydrate, dihydrate, and trihydrate,
among which, trihydrate is the most stable form.
4. Pharmacokinetics / Absorption
› Amoxicillin bioavailability reaches 95%
› Amoxicillin is a weak acid;
– In acidic media, it is better absorbed as a non ionized form (lipid soluble) for better penetration of
the intestinal membrane.
– In Alkaline media, it becomes ionized (water soluble) which means it will be eliminated non
absorbable.
5. Pharmacokinetics / Distribution
› amoxicillin was administered to eight chickens at a dose of 20 mg/kg of body weight
orally;
› Cmax 1.382 µg/ml
› Tmax 2 hr
› T1/2 2.433 hr
› AUC 4.506 µg/h/l
7. Amoxicillin MIC
46, 90%
5, 10%
amoxicillin MIC for 51 Clostriduim Perfringes Strains
MIC = 0.03 µg/ml MIC = 0.06 µg/ml
8. Bacterial Cell Wall Structure
› Peptidoglycan constitute almost 95% of the cell wall in some Gram positive bacteria
and as little as 5-10% of the cell wall in Gram negative bacteria.
9. Mechanism of action
› Amoxicillin acts by inhibiting the synthesis of bacterial
cell wall.
› It inhibits cross linkage between the linear
peptidoglycan polymer chains that make up a major
component of the cell walls of both Gram positive and
Gram negative bacteria.
10. Spectrum of activity
› Bactericidal antibiotic against wide range of gram+ve and gram-ve bacteria:
› Clostridium spp.
› E. coli
› Salmonella spp.
› Penicillin sensitive staphylococci
12. Dosage
› 20mg/kg bird live weight/day for 3 - 5 consecutive days.
› 1 bottle for 10 tons of live body weight.
13. Administration
› Turn off drinkers for 2 hours.
› Calculate number of amoxicillin WSP bottles to administer.
› Dissolve the contents of each bottle in a small amount of water.
› Immediately add this solution to a volume of water representing bird’s expected
water consumption over the next 2-3 hours.
› Once all the medicated water is consumed, the bird’s normal fresh water supply must
be resumed.
› Repeat this procedure daily for 3-5 days.