Artifacts in Nuclear Medicine with Identifying and resolving artifacts.
Polyene and polypeptide antibiotics
1. G Vijay Narasimha Kumar
Asst. Professor,
Dept. of. Pharmacology
Sri Padmavathi School of Pharmacy
2. CLASSIFICATION OF POLYENES:
AMPHOTERICIN –B
NYSTATIN
HAMYCIN
CLASSIFICATION OF POLYPEPTIDES:
BACITRACIN
POLYMYXIN-B
COLISTIN/POLYMIXIN-E
DACTINOMYCIN/ACTINOMYCIN--D
3. It is obtained from streptomyces Nodosus.
It is amphoteric in nature.
It is a polyene group of anti fungal antibiotic.
It is composed of large lactone ring with several
conjugated double bonds
4. AMPHOTERICIN –B binds to ergosterol which is a fungal cell membrane
sterol
It alters the permeability of fungal cell membrane by forming pores.
CELL DEATH
leads to
5. The sterol of mammalian cell membrane is cholesterol
for which amphotericin –b has less affinity.
Therefore, drug shows selective toxicity to fungal cell.
If it is binds to human membrane sterol then it may
cause drug toxicity.
RESISTANCE to AMPHOTERICINE –B is associated with
a replacement of ergosterol by other sterols in fungal
plasma membrane
6. ABSORPTION:-
It is poorly absorbed from GIT.
Oral administration is effective only against fungal
infections of intestine, and not for the treatment of
SYSTEMIC FUNGAL INFECTIONS .
It is therefore,administered by SLOW IV INFUSION.
7. DISTRIBUTION:-
It is widely distributed throughout the body.
It does not penetrate into CSF.
It binds to sterols in tissue and lipoproteins in plasma.
Plasma t1/2 --15 days.
13. Used in the treatment of invasive aspergillosis in immuno
compromised & non immuno compromised.
Used in the treatment of mucormycosis(an
opportunistic fungal infection in lungs)
Used in the treatment of Disseminated rapidly
progressing Histo plasmosis,
Coccidioidomycosis,
Meningeal coccidioidomycosis,
Blasto mycosis.
14. It is also used TOPICALLY to treat oropharyngeal
candidiasis and cutaneous candidiasis.
It is most effective dug for resistant cases of KALA AZAR
& MUCO CUTANEOS LEISHMANIASIS.
DOSE:
1-2gms
15. o It is obtained from s.nouresi.
o It is similar to amphotericin –B in antifungal action and
other properties.
o Due to its higher systemic toxicity ,it is used only locally in
superficial candidiasis.
o It is not absorbed orally ,can be used for monilial diarrhoea.
16. THERAPEUTIC USES
It is used in the treatment of monilial vaginitis.
It is used in the treatment of oral candidiasis.
It is used in the treatment of corneal conjunctival and
cutaneous candidiasis in the form of ointment.
SIDE EFFECTS
Nausea
Bad taste in the mouth.
DOSE:
1 lacu b.d
17. It was isolated from S.pimprina .
It is similar to nystatin but more water soluble .
Use is restricted to topical application for oral thrush
,cutaneous candidiasis, monilial & trichomonas vaginitis &
otomicosis by aspergillus.
DOSE: 5 lac u/g oint ,
2 lac u/ml susp for topical use.
19. It is obtained from bacillus subtilis.
It is active mainly against GRAM POSITIVE ORGANISM
(Both cocci &Bacilli),NEISSERIA,H.INFUENZA & few other
bacteria also affected.
20.
21. BACITRACIN not absorbed orally.
It is not given parenterally because of HIGH
TOXICITY especially to the kidneys.
It is used topically –skin and eye infections.
Generally in combination with polymixin , neomycin
etc…
23. The polymyxins are cation polypeptides that bind to
phospholipids on the bacterial cell membrane of gram-
negative bacteria.
They have a detergent-like effect that disrupts cell
membrane integrity, leading to leakage of cellular
components and ultimately cell death.
24. Polymyxins are concentration-dependent bactericidal agents
with activity against most clinically important gram-negative
bacteria, including
P. aeruginosa,
E. coli,
K. pneumoniae,
Acinetobacter species
Enterobacter species.
25. Only two forms of polymyxin are in clinical use today,
Polymyxin B
Colistin (polymyxin E)
Polymyxin B is available in parenteral, ophthalmic,
otic, and topical preparations.
Colistin is only available as a prodrug, colistimethate
sodium, which is administered IV or inhaled via a
nebulizer.
26. The use of these drugs has been limited for a long time,
due to the increased risk of nephrotoxicity and
neurotoxicity (for example, slurred speech, muscle
weakness) when used systemically.
However, with the increase in gram-negative resistance,
they have seen a resurgence in use and are now
commonly used as salvage therapy for patients with
multidrug-resistant infections.
27. POLYMIXIN -B SULFATE is used topically in
combination with other drugs in the treatment of
skin ear &eye infections.
It can be given orally for oropharyngeal
decontamination or the suppression of intestinal
flora in patient with high risk of endogenous
infections.
Colistin sulfate can be given orally for treating GIT
infection.
28.
29. Actinomycin D is a well-known antibiotic of the
actinomycin group that exhibits high ANTIBACTERIAL
and ANTITUMOR activity.
Actinomycin are extracted from streptomyces.
30. Dactinomycin binds to double stranded DNA through
intercalation between adjacent guanine-cytosine
base pairs.
Inhibits the all forms of DNA dependent RNA synthesis.
31. Actinomycin is a clear, yellow liquid administered
intravenously and most commonly used in treatment of
a variety of cancers, including
Gestational trophoblastic neoplasia
Wilms' tumor
Rhabdomyosarcoma
Ewing's sarcoma
32. Sometimes it will be combined with other drugs
in Chemotherapy regimens, like the VAC regimen
(with Vincristine and Cyclophosphamide) for treating
Rhabdomyosarcoma and Ewing's Sarcoma.
ADVERSE EFFECTS :
Bone marrow suppression,
Fatigue,
Hair loss,
Mouth ulcer,
Loss of appetite,
Diarrhea.