الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 117 |  |  |
| | | from | 117 | | |
Abstract
4
Novel aminophosphonates compounds were synthesized via one pot and threecomponent
reaction. 4-aminoantipyrene was incorporated as a base amine and
different aldehydes were used. The three precursors, aromatic diamines 1, carbonyl
compounds 2 (aldehyde), and triphenylphosphite 3 in acetonitrile were reacted
with the aid of Lewis acid catalyst (10 mol. %) of LiClO4. The reaction continued
for 3 days with high separated yields.
Schematic Illustration - Synthesis of α-aminophosphonates from 4-aminoantipyrene, different aldehydes and
triphenylphosphite The molecular structures of α-aminophosphonates (4a-j) were affirmed by IR, 1H
NMR, 13C-NMR and mass spectral analysis (for details cf. the experimental data).
The antimicrobial activity of α–aminophosphonates was tested against Gramnegative
bacteria, Escherichia coli; Gram-positive bacteria, Staphylococcus
aureus; a fungus, Aspergillusniger; and a yeast, Candida albicans.
Three of them (4f-h) exhibited high biological activity and were selected for drug
delivery studies. Carrageenan (CAR) based cryogel system was established as a
delivery vehicle. Physical and mechanical testing indicated that pure carrageenan
cryogel is very brittle and inadequate for drug loading. With the aid of cellulose
nanofibrills (CNF) as reinforcing material and glyoxal as a cross-linking agent,
porous cryogels with improved mechanical properties were obtained. Among all,
CAR-7 presents the optimum cryogel sample, which contained around 16% CNF
and 0.2mL/15mL polymer blend. CAR-7 demonstrated highest mechanical
compressive strength, porosity (80%), and (75%) swelling capacity. The release
profiles of the aforementioned active compounds (4f-h) from carrageenan cryogels
was investigated. Sustainable release behavior over 24 hours was observed for the
samples that might be attributed to formation of interconnected network between
CAR and CNF molecular chains.
The antibacterial activity of loaded carrageenan cryogels was tested against
Staphylococcus aureus and the results showed marginal differences between
samples. CAR-9 (loaded with 4f) showed the highest reduction percentage in
number of bacterial colonies (99.94%) followed by CAR-11 (loaded with 4h,
99.3%) and finally CAR-10 (loaded with 4g, 99.29%) when compared to the
control.