342
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
SYNTHESIS OF SUPERCHARGED CHITOSAN DERIVATIVES
Akhmedov O.R.
Abdurakhmanov J.A.
Shomurotov Sh.A.
Turaev A.S.
Institute of Bioorganic Chemistry of the Academy of Sciences of Uzbekistan,
Tashkent city, Republic of Uzbekistan
е
-mail: akhmedov.oliy@gmail.com
https://doi.org/10.5281/zenodo.17337348
Relevance
: Modern polymer chemistry is actively evolving toward the development of
functionalized biopolymers with tailored physicochemical and biomedical properties. Chitosan, a
derivative of chitin, is a polymer containing reactive amino groups, which makes it a promising raw
material for the design of novel biologically active macromolecular systems. One of the key
requirements for chitosan derivatives is their solubility under neutral or mildly alkaline conditions.
However, the limited solubility of native chitosan significantly restricts its practical applications.
Therefore, the development of highly charged chitosan derivatives remains a relevant and promising
research direction. In this context, the introduction of cationic groups into the chitosan backbone can
enhance not only its solubility at neutral or slightly alkaline pH values but also its inherent biological
activity.
Purpose of the study:
Synthesis of Supercharged Chitosan Derivatives Exhibiting Diverse
Physicochemical Characteristics.
Materials and methods:
1 g of chitosan hydrochloride (molecular weight 230.0 kDa, degree
of deacetylation 85%) was dispersed in 100 mL of ethanol and allowed to swell for 2 hours. After
swelling, a low-molecular-weight reagent was added at a molar ratio of chitosan to cyanoguanidine
= 1:1-4. The reaction mixture was stirred for 5-10 hours at 60-80°C. Upon completion, the precipitate
formed was separated by decantation, dissolved in 1% hydrochloric acid, and reprecipitated with
acetone. The resulting solid was redissolved in water and purified by dialysis for 48 hours, with five
changes of dialysis water. Finally, the purified product was subjected to lyophilization and analyzed.
Results:
Upon reaction of cyanoguanidine with the amino groups of chitosan, a nucleophilic
addition occurs, leading to the formation of guanidinium moieties. The conducted studies
demonstrated that by varying the reaction conditions specifically the molar ratio of reactants, reaction
time, and temperature it is possible to obtain chitosan derivatives with a degree of substitution ranging
from 0.15 to 0.64 mol%. The presence of guanidinium groups in the chitosan backbone was
confirmed by FTIR and NMR spectroscopy. Introduction of guanidinium fragments into the
macromolecular chain significantly improved the solubility of chitosan across a wide pH range. While
native chitosan is insoluble in neutral and alkaline media, the synthesized derivatives remained
soluble within the pH range of 3 to 9.
In addition, the included guanidine groups increased the overall charge of chitosan (38 mV)
and the ζ-potential value was 45-58 mV.This increase in positive charge may have a direct impact on
the physiological properties of chitosan. For instance, stronger electrostatic interactions with cell
membranes could enhance both its antimicrobial activity and its cell adhesion capacity, thereby
broadening the potential biomedical applications of guanidinium-functionalized chitosan.
Conclusions:
Thus, the synthesized supercharged chitosan derivatives containing guanidinium
groups exhibit improved physicochemical characteristics, including an expanded solubility range and
343
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
an increased positive surface charge. These properties indicate the potential of the modified chitosan
derivatives for use in various biomedical applications.
This study received financial support from the Innovative Development Agency of the Republic
of Uzbekistan (Project No. FL-8824063355).
