Research Publications

Now showing 1 - 3 of 3

Open Access
In vitro release kinetics of bioactive compounds (gallic acid, ellagic acid, and eugenol) from chitosan polymer and the bioactivity of herb-loaded chitosan–CuO nanocomposites
(Nature Research, 2025-10-13) Ekanayake, G; Wijayawardana, S; Jayanetti, M; Thambiliyagodage, C; Liyanaarachchi, H; Mendis, A
The biological efficacy of nanocomposites comprised of chitosan, CuO nanoparticles, and extracts of Phyllanthus emblica, and Syzygium aromaticum was studied. The study assessed the pH– and ionic strength-responsive controlled release of the bioactive compounds, gallic acid, ellagic acid and eugenol, from the chitosan biopolymer. Release data were fitted into zero-order, first-order, Korsmeyer–Peppas (KP), Peppas–Sahlin (PS), Higuchi, and Hixson–Crowell kinetic models to evaluate the release mechanism. According to KP and PS models (R2 ≥ 0.96), release was governed by quasi-Fickian diffusion (n < 0.43), where the diffusion occurs along with the polymer relaxation and swelling. P.emblica-coated chitosan (PeC) composite exhibited a burst release at acidic media conditions, and a quasi-Fickian diffusion at pH 5.5–7.4. Higher ionic strength caused salting-in effects for PeC in 0.4 M media, resulting in a transiently increased release. In acidic conditions, diffusion-controlled release was observed for S.aromaticum-coated chitosan (SaC) composite, with the optimal release at pH 4 media. Release was facilitated by hydrophobic nanochannels at elevated pH (8.5–10) and ionic strength of 0.5 M NaCl. The PS model’s relaxation contributions were significant at 0.4 M NaCl and 5 mg drug loading. Both composites demonstrated enhanced release at physiological conditions (0.1–0.2 M NaCl, pH 7.4). Sustained release of SaC was achieved in near-neutral/moderate ionic strength media, whereas PeC exhibited sustained release in acid/low ionic strength media. The PeC and SaC composites showed IC50 values of 10.78 µg/mL and 19.27 µg/mL for the DPPH radical scavenging ability, respectively. Recorded IC50 values for the egg albumin denaturation assay were 467 µg/mL and 390.44 µg/mL, respectively. The antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus showed maximum inhibition zones of 11.83 ± 0.06 mm (Chitosan: CuO 1:2), 12.67 ± 0.20 mm (1:4), 16.50 ± 0.09 mm (1:4), and 11.83 ± 0.08 mm (4:1), respectively. Among the herbal-coated samples, SaC exhibited the highest activity of 23.67 ± 2.84 mm against E. coli
Open Access
A Study on Conscinium fenestratum and Chitosan Biopolymer Composite for Ayurvedic Drug Delivery
(Faculty of Humanities and Sciences, SLIIT, 2024-12-04) Alwis, M; Jayanetti, M; Thambiliyagodage, C
This study delves into the synergisti c amalgamati on of Coscinium fenestratum, an Ayurvedic medicinal plant, and chitosan biopolymer. This results in the innovati ve Venivel Chitosan Composite, which has established a pioneering drug delivery system. Subsequently, the composite material, Venivel Chitosan Composite, was formulated by integrati ng Coscinium fenestratum extract and chitosan biopolymer. Structural characteristi cs of Chitosan biopolymer and Venivel Chitosan Composite were determined via scanning electron microscopy (SEM), off ering valuable insights into their morphological features. Furthermore, a comprehensive characterizati on of the composite was achieved through the analysis of X-ray diff racti on (XRD) patt erns, elucidati ng its crystalline structure. A meti culous examinati on of the in vitro drug release profi le revealed a predominant diff usion mechanism, indicati ng the potenti al suitability of this system for applicati ons in wound healing treatments. In conclusion, integrati ng Coscinium fenestratum with chitosan biopolymer presents a versati le composite with promising anti bacterial, anti oxidant, and anti - infl ammatory properti es, elevati ng its potenti al for targeted and controlled ayurvedic drug delivery applicati ons.
Embargo
Kinetic study of in vitro release of curcumin from chitosan biopolymer and the evaluation of biological efficacy
(Elsevier B.V., 2024-09) Wijayawardana, S; Thambiliyagodage, C; Jayanetti, M
Sustained release of curcumin from the polymeric carrier system chitosan, a natural biopolymer material derived from chitin originated from natural shrimp shell waste, was studied. Six kinetic models, zero order, first order, Korsmeyer–Peppas (KP), Peppas – Sahlin (PS), Higuchi, and Hixson–Crowell, were applied to study the drug release kinetics. The release mechanism of the drug from the curcumin-chitosan composite was evaluated by changing the pH, ionic strength of the release media, and drug concentration. KP and PS models were selected among the studied models to investigate the drug release mechanism from the chitosan biopolymer based on the R2 values (R2 > 0.99). The model constants m in the PS model and n in the KP model stand for the case II relaxation and Fickian diffusion contribution, respectively. The n being < 0.43 in the KP model suggests that the Fickian diffusion governs the drug release. Furthermore, there is a noticeable difference between the values obtained for model parameters m and n in the PS and KP models, indicating that Case II relaxation and Fickian diffusion play crucial roles in the curcumin release mechanism from chitosan. Polymer relaxation has been proven to play a predominant role in releasing curcumin from the composite at lower ionic strengths and higher pH values. Anti-inflammatory activity was tested using the egg-albumin denaturation assay, and the diphenyl-2-picrylhydrazyl assay was carried out to determine the antioxidant activity of the composite. The composite material showed IC50 values of 0.29 mg/ mL and 1.08 mg/ mL for anti-inflammatory and anti-oxidant activities, respectively. The drug composite has shown antibacterial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus, which are highly effective against S.aureus. The resulting inhibition zones for S.aureus were 13.34 ± 0.34 mm, 16.34 ± 0.60 mm, and 13.34 ± 0.73 mm for 5, 10, and 20 mg/ml concentrations, respectively. The drug composite’s minimum inhibitory concentration/ minimum bactericidal concentration ratio for S.aureus, K. pneumoniae, and P.aeruginosa was greater than 4, suggesting that they cause bacteriostatic effects.

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