Biomedical Engineering Reference
In-Depth Information
O
NH
2
O
CH
3
N
HN
N
HN
O
N
O
N
N
N
HO
HO
HO
O
O
O
N
3
Zidovudine
Didanosine
Zalcitabine
NH
2
O
NH
CH
3
N
N
N
HN
COOH
N
O
N
N
O
H
2
N
H
2
C
N
HO
HO
H
2
C
HO
S
COOH
O
O
Stavudine
Lamivudine
Abacavir
NH
2
NH
2
F
N
N
N
N
N
O
N
O
CH
2
O
(CH
3
)
2
CH
O
C
O
O
P
O
HO
S
(CH
3
)
2
CH
O
C
CH
2
O
O
COOH
O
CH
3
O
HC
HC
COOH
Emtricitabine
Tenofovir disoproxil fumarate
FIGURE 24.1
Structures of a number of nucleoside reverse transcriptase inhibitors (NRTIs).
24.2.1.2 Didanosine
Structure
(Figure 24.1): 2
-Dideoxyinosine (ddI), Videx
®
, Videx EC.
Activity spectrum
: HIV (types 1 and 2).
Mechanism of action
: Targeted at HIV RT, acts as chain terminator, following intracellular phos-
phorylation to 2
′
,3
′
′
,3
′
-dideoxyadenosine (ddA) 5
′
-triphosphate, and, after removal of the diphosphate
group, incorporation of ddA 5
-end of the viral DNA chain.
Principal indication(s)
: HIV infection, especially advanced HIV disease, in combination with other
anti-HIV agents.
Administered
: Orally at 400 mg/day (Videx: two 100 mg tablets twice a day or two 200 mg tablets
once a day; Videx EC: one 400 mg capsule once a day).
′
-monophosphate at the 3
′
