Carboxymethylation of Phoenix dactylifera L palm tree cellulose and its evaluation as pharmaceutical suspending agent
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Date
2024-06
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Addis Ababa University
Abstract
Phoenix dactylifera L palm tree is a plant with great sustainability and renewability in nature and
widely spread across much of Middle East, tropical Africa including Ethiopia. Its fiber biomass
mainly comprises lignocellulose, and used as an alternative source of cellulose. The objective of
this study was to extract and characterize cellulose from the leaves and leaf base of local Phoenix
dactylifera L palm tree; modify the extracted cellulose to carboxymethyl cellulose (CMC) and
evaluate the CMC as pharmaceutical suspending agent. Leaves and leaf base of Phoenix
dactylifera L palm tree were individually subjected to extraction of cellulose, followed by the
carboxymethylation process by utilizing monochloroacetic acid and sodium hydroxide.
Characterization techniques including Fourier Transform Infrared Spectroscopy, Scanning
electron microscopy, X-Ray Diffraction, and Thermogravimetric Analysis were employed to
assure the successful extraction of cellulose as well as the modification of cellulose to CMC. The
percent of cellulose yields on a dry weight basis was found to be 36.7 + 0.97 % for cellulose
extracted from palm tree (Phoenix dactylifera L) leaves and 41.3 + 1.08 % from leaf base. The
maximum degrees of substitutions of CMC were 0.889 for (Carboxymethyl cellulose derived
from Phoenix dactylifera L tree leave) (L-CMC) and 0.667 (for Carboxymethyl cellulose derived
from Phoenix dactylifera L Leaf base cellulose (LB-CMC)) based on dry weight conditions. The
yield of CMC ranged from 0.889 + 0.003 g/g (for L‐CMC) to 0.179 + 0.001 (for LB‐CMC).
L-CMC and LB-CMC were evaluated as suspending agents in metronidazole benzoate
suspensions. The suspensions were prepared using 0.5%, 1%, 1.5%, and 2% w/v of L-CMC, and
LB-CMC, and compared with suspensions prepared from commercial carboxyl methyl cellulose
(C-CMC) in similar concentrations. The resulting suspensions were evaluated for their visual
appearance, pH, sedimentation volume (%), rheology, redispersibility, and in vitro drug release
profile, and also stability studies at accelerated condition were performed for 3 months. The flow
rate and redispersibility of the metronidazole benzoate suspension prepared with L-CMC were
significantly lower than those with C-CMC and higher than those prepared with LB-CMC at 1 %
w/v suspending agent concentrations(p>0.05). The sedimentation volume of the formulations
was in the order of C-CMC > L-CMC> LB-CMC (p>0.05). Additionally, the dissolution rate
profiles of all the prepared metronidazole benzoate suspensions remained similar to the
Negazole, Camezola, and Metrogly with f2 > 50.
The results indicate successful carboxymethylation of palm tree cellulose, and yielding CMCs
with desired physicochemical properties as pharmaceutical suspending agent.
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Keywords
Phoenix dactylifera L palm tree, Cellulose, carboxyl methyl cellulose, suspending agent