Biomedical Engineering Reference
In-Depth Information
Liposomes are widely used drug carriers for macrophage-specii c
antibacterial drug delivery (see
Figure 14.6 above
)
.
In one of the experi-
ment, streptomycin loaded liposomes were intravenously injected into
the infected mice led to the decrease of the mycobacterium count in the
spleen but not in the lungs but prolonged mouse survival and reduced
drug toxicity was observed as compared to the free drugs [76]. According
to the Klemens
et al
, gentamicin loaded liposomes were evaluated for
the antibacterial activity in
M. avium
infected mouse model. It signii -
cantly reduced the bacterial count in spleen as well as liver compared
to free drug [77]. Deol and Khuller developed stealth liposomes for the
targeted delivery of anti-TB drugs to the lungs. Liposomes composed of
phosphatidylcholine, cholesterol, dicetylphosphate-o-steroylamylopectin
and monosialogangliosides / distearylphosphatidylethanolaminepoly
(ethylene glycol) 2000. At er intravenous administration in healthy and
tuberculosis infected mice, increase in accumulation from 5.1% for con-
ventional liposomes to 31% for Poly ethylene glycolated liposomal sys-
tems at er 30 min was observed. Drug uptake levels in the lungs increased
to approximately 40% for the poly ethylene glycolated nanocarriers
when administered to pretreated infected animals at er 30 min 3[78].
Ahmed
et al.
developed various nanoemulsions of RIF (47 and 115nm)
using GRAS listed excipients (US-FDA). As a result the entrapment ei -
ciency was 99% with excellent stability over 3 months with slight increase
in particle size and initial burst drug release of 40-70% at er 2h [79].
Anisimova
et al.
encapsulated RIF, INH and streptomycin within poly-(n-
butylcyanoacrylate) (PBCA) and poly-(isobutylcyanoacrylate) (PIBCA)
nanoparticles and their accumulation in the human blood monocytes was
tested
in vitro
[80]. Econazole and moxil oxacin loaded PLG nanopar-
ticles were prepared by the multiple emulsion and solvent evaporation
technique. As a result the drug levels in lungs, liver and spleen lasted till
6 days as compared to the pure drugs which were cleared within 12-24
h. In
M. tuberculosis
infected mice, only 8 doses of polymeric nanopar-
ticles were sui cient to suppress bacterial clearance as compared to the
pure drug which requires 56 doses daily of moxil oxacin and 112 doses of
econazole twice a day. Further to improve treatment there was addition of
third drug for tubercular chemotherapy [81].
Encapsulation of RIF, INH, and PYZ in alginate microspheres and oral
administration to guinea pigs, maintain the drug concentration in plasma
for 4-5 days and in the organs for 7-9 days. Weekly treatment of alginate
microspheres resulted in the complete bacterial clearance in the organs of
infected guinea pigs at er 8 oral doses daily as compared to the admin-
istration of free drugs [82]. Alginate-chitosan coated microcapsules were
