2. Antileprotic drugs
• Leprosy is an infectious disease that causes severe,
disfiguring skin sores and nerve damage in the
arms, legs, and skin areas around the body.
• Leprosy is an infectious disease caused by a
bacillus, Mycobacterium leprae.
3.
4. • The two forms of disease are :
• (i) tuberculoid leprosy : in this skin and peripheral
nerves are involved resulting in motor and sensory
changes in affected area.
• (ii) Lepromatous leprosy : Skin gets thickened and
oedematous and painless nodular lessions occur in
it, which may become necrotic and ulcerate,
releasing large number of mycobacteria.
OEDEMATOUS
5. Why name came tuberculosis
leprosy
• As early as the 1940s scientists had suggested
that TB, caused by Mycobacterium tuberculosis,
might cross-immunise sufferers from leprosy,
caused by the related Mycobacterium leprae.
• The idea was born when the BCG vaccine
for TB occasionally appeared to be effective
against leprosy as well.
6. • The development of anti mycobacterial agents
started when It observed that sulphonamides are
only slightly effective on tuberculosis.
• A slight structural modification of sulphonamides
results In development of dapsone.
• It has feeble anti tubercular activity but is most
effective in the treatment of leprosy.
DAPSONE
SULPHONAMIDES
7. • Classification of antileprotic agents
• The antileprotic agents used therapeutically can be
placed under following categories : (i) Sulphones
e.g. Dapsone, (ii) Thiosemicarbazone derivatives
(iii) Phenazine (diaminophenazine) derivatives e.g.
clofazimine T
• The other drugs which exhibit activity agianst M.
Leprae are : (a) Long acting sulphonamides (b)
Thioacetazone (c) Ethionamide (d) Antibiotics like
rifampicin.
9. 1. Dapsone
• Dapsone is a sulphone. The term sulphone is used
for all the derivatives containing 4, 4'-diamino
diphenyl sulphone. In this class, the amino group of
sulfamoyl group of sulphonamides is replaced by p-
aminophenyl group.
SULPHONAMIDES
10. • Physical properties
• It occurs as a white or creamy white crystalline
powder.
• It Is odourless and has slightly bitter taste.
• It Is very slightly soluble In water, and soluble in
acetone and In dil. mineral acids.
11. • Chemical properties
• 1. Diazotisation reaction : Dapsone, when treated
with sodium nitrite in presence of hydrochloric
acid, both primary aromatic amino groups are
converted to diazo groups.
• 2. When Dapsone is condensed with
cinnamaldehyde, followed by addition of sodium
blsulphite, it gives solapsone.
12. • Stability and storage
• Pure dapsone Is stable. But In presence of traces of
impurities and water, It is discoloured. Hence It Is
stored In well-closed light-resistant containers.
• Uses : (I) it is mainly used to treat both forms of
leprosy. However, It is a drug of choice to treat
leprosy in combination with rifampicin. (ii) It has a
suppressive action on malaria parasite. (ill) It is also
used in the treatment of dermatitis herpetiformis
and relapsing polychondritis.
• Pharmaceutical formulation : Dapsone tablets
• Brand names : Dubronax
13. 2. Solapsone
• Properties : it is a white powder. It is very soluble in
water. It is converted In body to dapsone.
• Storage : Store In well-closed light-resistant
containers.
• Uses : It is used to treat leprosy
14. 3. Thiambutosine
• Physical properties
• It occurs as a white or creamy white crystalline
powder. it s odourless and has a bitter taste. It Is
very soluble in water but soluble in acetone.
• Stability and storage
• It is affected by light and hence it is stored in
tightly-closed light resistant containers.
15. • Uses : (i) It Is used to treat leprosy. particularly in
patients who cannot tolerate dapsone. (ii) It Is
proved useful in patients with severe neuritis.
• Pharmaceutical formulations 1. Thiambutosine
tablets.
• Brand names : Ciba 1906.
16. 4. CLOFAZIMINE
It contains 2, 10-dihydrophenazine heterocyle.
Physical properties
It occurs as dark red crystals or an orange red micro-
crystalline powder.
It is practically Insoluble in water, soluble in
dimethylformamide and In macrogol 400.
17. Stability and storage
It is a stable compound. It is stored in well-closed
containers.
Uses : (i) It is used to treat leprosy, especially for
dapsone resistant bacilli. (ii) It is also used to treat
Iepromatous leprosy of recent onset.
Brand names : Clofozine, Lamprene.
