BIBECHANA Vol. 22, No. 2, August 2025, 122-130 ISSN 2091-0762 (Print), 2382-5340 (Online) Journal homepage: http://nepjol.info/index.php/BIBECHANA Publisher:Dept. of Phys., Mahendra Morang A. M. Campus (Tribhuvan University)Biratnagar Characterization of essential ingredients for designing biopolymer-based transdermal patches Prasamsha Panta1,2,3, Elina Maharjan3, Holger Schönherr2,∗, Rameshwar Adhikari3,4,5,∗∗, Achyut Adhikari5, Rajani Malla1,∗∗∗ 1Central Department of Biotechnology, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal 2Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and (Bio)Technology (Cµ) Physical Chemistry I, University of Siegen, Adolf-Reichwein-Str.2, 57076 Siegen,Germany 3Nepal Polymer Institute (NPI), P. O. Box 24411, Kathmandu, Nepal 4Central Department of Chemistry, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal 5Research Center for Applied Science and Technology (RECAST), Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal ∗Corresponding authors. Email: ∗ schoenherr@chemie.uni-siegen.de ∗∗ nepalpolymer@yahoo.com ∗∗∗rajanimalla2000@gmail.com Abstract The study aimed to characterize the key ingredients used in developing biopolymers-based transdermal patches using Fourier Transmission Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and rheological analysis. While FTIR spectroscopy and SEM were used to investigate the structural properties and intermolecular interaction within chitosan (CH), methylcellulose (MC), and carboxymethyl cellulose (CMC) as well as wintergreen essential oil (WG oil), the TGA revealed the thermal degradation profiles of CH, MC, and CMC. Rheological analyses revealed that the polymer concentration and the solvent chosen significantly influenced the processability of the poly- mers. TGA analysis demonstrated that an initial decomposition of CH took place at 275 0C, while MC and CMC exhibited initial degradation around 260 0C. Based on the structural, rhe- ological, and thermal properties, the suitability of the characterized biopolymer for fabricating the transdermal patch was demonstrated. Keywords Core ingredients, transdermal patch, wintergreen essential oil, biopolymers Article information Manuscript received: January 27, 2025; Revised: March 8, 2025; Accepted: March 10, 2025 DOI https://doi.org/10.3126/bibechana.v22i2.74648 This work is licensed under the Creative Commons CC BY-NC License. https://creativecommons. org/licenses/by-nc/4.0/ 122 http://nepjol.info/index.php/BIBECHANA schoenherr@chemie.uni-siegen.de nepalpolymer@yahoo.com rajanimalla2000@gmail.com https://doi.org/10.3126/bibechana.v22i2.74648 https://creativecommons.org/licenses/by-nc/4.0/ https://creativecommons.org/licenses/by-nc/4.0/ Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 123 1 Introduction Transdermal patches (TP) belong to advanced non- invasive drug delivery systems. They offer sustained and controlled release of active pharmaceutical in- gredients (APIs) through the skin (dermal region) into the systemic circulation [1]. This process by- passes the conventional oral and injection routes [2, 3]. Current trends and innovations in transder- mal patches include smart patches that integrate dose monitoring and adjustable drug release via wearable electronics [4], and combination therapy through which larger molecule drugs like vaccines and peptides can be delivered. Similarly, for envi- ronmentally sustainable designs, biopolymer-based patches that incorporate biodegradable polymers such as chitosan, cellulose-based polymers, gelatin, and starch can be prepared [5, 6]. Among these polymers chitosan (CH), methyl- cellulose (MC), and carboxymethyl cellulose (CMC) have been used in combination with con- ventional medicines [7] essential and fixed oils [8], and herbal extracts [9] for the preparation of trans- dermal patches. CH, MC, and CMC are environmentally friendly and versatile biopolymers with a wide range of ap- plications [10] such as in food industries, water treatment, cosmetics and personal care, agriculture industries, medical, pharmaceutical, and healthcare products [11], textile industries [12], painting indus- tries, construction industries. CH is a natural biopolymer obtained by the deacetylation of chitin, where the removal of acetyl groups affords amine groups [13]. CH materials (for chemical structure see Figure 1) are environmen- tally friendly and non-toxic materials that can also be used as an antibacterial and antifungal agent, tissue engineering, skincare, hair care, and drug de- livery systems [14–16] and as dietary supplements. MC is produced by treating cellulose with methyl chloride, which makes MC water soluble to form clear viscous solutions. MC is non-toxic and non-allergic, which makes this polymer suitable for use in food and pharmaceutical industries [16]. MC can be utilized in various fields for its proper- ties and applications as a thickener and stabilizer, gelling agent, emulsifier, wound care, food packag- ing [17, 18], and drug delivery system [19]. The structure of MC is illustrated in Figure 1. CMC is a natural polymer derived from cellu- lose found in plant cell walls. CMC is produced by chemical modification of cellulose, where car- boxymethyl groups (-CH2-COOH) are introduced into the cellulose backbone. CMC (see Figure 1) is water-soluble, which makes it useful in various fields. The applications of CMC in different areas like thickener, binder, thickening agent, excipient, controlled release, wound dressing, and drug deliv- ery system [20, 21]. CMC is an ideal choice for a drug delivery system capable of encapsulating the active drug. CMC exhibits film-forming properties, biocompatibility, and capacity for controlled drug release [22]. Figure 1: Illustration of chemical structures of chi- tosan (CH), methylcellulose (MC), carboxymethyl cellulose (CMC), and methyl salicylate, the primary component of wintergreen essential oil (WG oil) Wintergreen essential oil (WG oil), derived from the leaves of wintergreen plants (Gaultheria procumbens), commonly known as Dhasingare in Nepali language, is a natural pain reliever with a long history of medicinal use. The oil is composed of more than 90% methyl salicylate (chemical struc- ture given in Figure 1), a chemical compound well- known for its pain-fighting properties [23]. It has been reported that the WG oil acts as an anti- inflammatory agent, making it effective for soothing muscle pain, and joint pain, and reducing swelling [24], and thus is a common ingredient in topical pain relief products such as balms and ointments em- ployed in the treatment of rheumatism and arthri- tis [25]. A key development arising from combin- ing WG oil with biopolymers could lead to new, convenient, and affordable transdermal patches for pharmaceutical applications [26–28]. This combination of natural pain relief and in- novative materials holds promise for the future of pain management. The overall characteriza- tion of biopolymers is crucial in developing any kind of drug delivery system, including transdermal patches. The present work aims at characterizing CH, MC, CMC, and WG oil to investigate their suitability as building blocks for the fabrication of medicated transdermal patches. The details on the performance of the patches will be the object of other reports (for example [29]. 2 Materials and Methods 2.1 Materials Chitosan (PCode 102433232) and carboxymethyl cellulose (PCode 1002577718) were purchased from Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 124 Sigma Aldrich, and low substitution methylcel- lulose (PCode 29217) was purchased from BDH Chemicals Ltd., Poole England. Acetic acid and glycerol were procured from Thermo-Fischer Scien- tific. Wintergreen (Gaultheria procumbens) essen- tial oil was purchased from Annapurna Pvt. Ltd. in Nepal. Milli-Q water was purified in the labo- ratory using a Millipore Direct Q8 system with a resistivity of 18.2 M cm (Millipore advantage A10 system, Schwalbach, with Millimark Express 40 fil- ter, Merck, Germany). All the chemicals were used as received. 2.2 Characterization Methods 2.2.1 Scanning Electron Microscopy (SEM) Analysis CH, MC, and CMC powder samples were mounted on a sample holder using conductive carbon tape. The samples were then sputter-coated with 20 nm of gold film to avoid charging and electron beam damage. A Camscan CS24 Scanning Electron Mi- croscope (Applied Beams, Beaverton, OR, USA), operated at an accelerating voltage of 25 kV, was used. 2.2.2 Fourier Transmission Infra-Red (FTIR) Spectroscopy Analysis Powder samples of each biopolymer were ground and mixed with potassium bromide (KBr) to form a pellet. The pellet was placed in an FTIR sample holder. Samples were analyzed using a Bruker Ten- sor 27 FTIR spectrometer (Ettlingen, Germany) us- ing 2 cm-1 of the resolution, number of scans 32 in the spectral range of 4000 cm-1- 400 cm-1. 2.2.3 Analysis (TGA) Approximately 10 mg of the powder sample of each biopolymer was placed in an airtight crucible and placed in the TGA instrument (Q500 V6.7 Build 203, Eschborn, Germany). The samples were ana- lyzed from 50 0CC to 850 0CC at a heating rate of 10 oC/min. 2.2.4 Rheological Measurement and Preparation of Patch 0.5 wt.- % of CH was dissolved in 1 vol.- % of acetic acid, and 1 wt.- % of MC and CMC was dissolved in Milli-Q water. The solution was stirred for 12 h and viscosity was measured using a Bohlin instru- ments rheometer at 37 oC, measuring a system of C25 DIN 53019 spindle. For the preparation of the transdermal patch, after the complete dissolution of CH and MC for 12 h. The MC solution was mixed with the CH so- lution and mixed for 3 h in a stirring plate. Then the mixture was poured in a 90 mm diameter Petri plate and dried in an oven at 45 oC for 2 days. Every experiment was performed 3 times and the average result along with the standard devia- tion has been presented. 3 Results and Discussion 3.1 Morphology of Biopolymers SEM analysis was conducted to investigate the particle shape, size, and surface characteristics of the biopolymers. Scanning electron micro- graphs (SEM) of biopolymer powders, with high- magnification SEM images of each sample displayed to the right, Figure 2. These micrographs reveal that chitosan (CH) exhibits a flake-like morphology with a smooth, non-porous surface [30] as evident in Figure 2a. No- tably, individual CH granules appear larger com- pared to MC (Figure 2b) and CMC (Figure 2c), potentially attributed to differences in the primary materials while preparing the polymers. Figure 2: Scanning electron micrographs of biopoly- mers: a) CH, b) MC, and c) CMC; a part of each micrograph on the left (indicated by a white rect- angle) has been magnified on the right. The most common initial material for CH is chitin [30], but MC and CMC are cellulose-based materials synthesized from plant cell walls [31, 32]. The cellulose-based polymers (MC and CMC) dis- play a fibrous structure and smaller particle sizes than CH granules [33]. In the case of CH, the de- gree of acetylation influences its particle morphol- ogy [34]. In contrast to CH and MC, CMC has been found to exhibit smaller particle sizes and a granular, ir- Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 125 regular structure, likely due to the substitution dur- ing its synthesis. Other factors that may contribute to the observed structural variations among CH, MC, and CMC include processing techniques and the chemicals used during preparation. 3.2 Spectroscopic Characterization of Biopolymers and WG Oil Figure 3a presents the FTIR spectra of CH, MC, CMC, and WG oil, revealing subtle differences across certain spectral regions. Figure 3b depicts the extended spectral region (2000 cm -1 to 600 cm -1) of the FTIR spectra of the samples. The re- gion provides a clearer understanding of the spec- tral similarities between MC and CMC, as well as the prominent spectral signature of methyl salicy- late, a key component of wintergreen essential oil. A broad band observed around 3400 cm-1 in all samples (CH, MC, CMC, and WG oil) is charac- teristic of O-H stretching vibrations. In CH, this broadband further confirms the presence of both hy- droxyl and amine groups [5]. Consistent with pre- vious findings by Santosh Kumar et al., a common band near 2925 cm-1 is observed in all attributed to C-H stretching vibration of aliphatic chains of chi- tosan backbone in CH [35], and methylene/methyl groups within the cellulose structures of MC, CMC and WG oil. In addition, for CH, a band at 1460 cm-1, char- acteristic of amine II vibrations (N-H bending), in- dicates the presence of free amino groups [36]. The CH2 bending vibration of the methylene group was observed at 1322 cm-1. Additionally, strong bands at 1167 cm-1 and 1089 cm-1 were assigned to C-O-C bending vibrations of glycosidic linkages (Figure 1) and C-O vibration of carbohydrates was observed respectively. In the case of MC, a band character- istic of C-O-C ether linkages was observed at 1460 cm-1 [37]. C-H bending vibrations and typical - glycosidic linkage in cellulose were observed at 943 cm-1. In the CMC spectrum, a characteristic peak of the carboxymethyl group was observed at 1606 cm-1, corresponding to asymmetric and symmet- ric stretching vibrations of COO- group [38]. C-H bending vibrations of methylene and methyl groups are observed at 1331 cm-1. Finally, a band at 1064 cm-1 can be attributed to C-O stretching vibrations of polysaccharides. In the case of WG, in agreement with Samira Mendes et. al., a band at 1584 cm-1 was attributed to aromatic C=C stretching vibrations, indicative of a benzene ring in methyl salicylate. C-O stretch- ing vibrations of ester linkages were observed at 1257.5 cm-1. Additionally, bands at 1095 cm-1 and 763 cm-1 were assigned to C-O stretching vibrations of alcohols/ phenols and aromatic C-H bending vi- brations, respectively [39]. Figure 3: FTIR spectroscopy analysis of a) CH, MC, CMC, and WG oil, and b) magnified view of the spectral region from 2000 cm -1 to 600 cm -1 3.3 Thermogravimetric Analyses of the Biopolymers The plot in Figure 4a represents the weight loss profile of CH, MC, and CMC. All the polymers ex- hibit a significant weight loss and increase in tem- perature, which shows the thermal decomposition of CH, MC, and CMC. Among the three polymers, CH appears to have the lowest thermal stability among the three biopolymers. This might indicate that CH decomposes more easily compared to MC and CMC. It seems that CMC has the highest ther- mal stability because the weight loss starts at higher temperatures and indicates more resistance to ther- mal degradation [10, 40]. The chemical structure and composition of these biopolymers play a cru- cial role in determining thermal stability. Figure 4b illustrates that for CH powder, the primary decomposition occurred at 274 oC, at- tributed to the breakdown of the polymeric struc- ture and the cleavage of glycosidic bonds (see Figure 1 for chemical structures). A final decomposition step was observed around 481 °C, which might be of different chemical bonds and functional groups within the CH structure. In the case of MC, the initial decomposition started around 260 0C, associated with the degrada- tion of the methylcellulose and the release of volatile degradation products and small organic molecules due to the breakdown of methyl ether groups. Fig- ure 3b indicates that MC undergoes approximately 10 % decomposition at 457 oC, which might be attributed to the breakdown of complex materials that remain still during the synthesis process. In contrast to the findings of Thomas et al. (2016), CMC exhibited an initial decomposition of around 38 % at 260 oCC, likely due to the degra- dation of both carboxymethyl groups and the poly- meric backbone. A second phase of decomposition occurred at about 700 oCC, with an approximate weight loss of 21 %, suggesting further breakdown into similar molecules. A residual mass was ob- served at ca. 800 oC, likely consisting of a carbona- ceous substance [41]. Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 126 Figure 4: Thermogravimetric analysis (TGA) curves of CH, MC, and CMC a) Weight loss as a function of temperature, b) Derivative weight loss curves. Measurements were conducted under a ni- trogen flow rate of 50 mL/min within a temperature ranging from 50 0C to 850 0C. Generally, higher onset temperatures indicate greater thermal stability. This notion is in agree- ment with earlier research works related to the sta- ble nature of the CMC, in which the latter was used for environmental applications [42], [43]. The results demonstrate better weight degradation sta- bility of the CMC compared to CH and MC. The TGA profile shows that the initial weight loss is due to moisture release, which is almost absent in the case of CH, MC, and CMC because the samples se- lected for analysis were stored in closed containers and freeze-dried before analysis. 3.4 Rheological Analysis of Biopolymers The rheological study aimed to assess the stability and overall performance of these polymers during processing and transdermal patch preparation. Fig- ure 5 illustrates the viscosity of CH, MC, and CMC as a function of concentration whereby water is used as a control solution. To simplify the preparation process, a lower concentration of CH was used to compare with the MC and CMC. Despite the lower concentration (0.5 wt.- %), CH exhibited a viscos- ity of 0.23 Pa.s whereas, the viscosity of MC and CMC was much lower. In the case of MC and CMC 1 wt.- % of solu- tion was used where the viscosity was found to be 0.04 Pa.s and 0.014 Pa.s respectively. In MC, the observed decrease in viscosity at specific temper- atures is attributed to its thermoreversible prop- erty, specifically the hydrophobic interactions of methoxy groups [44]. In the case of CMC, viscos- ity is significantly influenced by the degree of sub- stitution and the ionization state of the carboxyl group [45]. The difference in viscosity is likely due to the degree of deacetylation of chitosan [46] and the alignment of electrostatic forces, especially the positively charged amino group and glycosidic link- age [47]. Figure 5: The viscosity of CH, MC, and CMC solu- tions was determined using a rheometer concerning water. Accompanying photographs represent the visual appearance of the CH, MC, and CMC solu- tions. From the rheology study, it can be revealed that the molecular weight of the polymer, concentration, and solvent are crucial factors that affect the vis- cosity of the polymeric solution. As TGA analyses the decomposition and stability, rheology gives in- formation about the flowability due to structural breakdown. 3.5 Structural Characterization of the Transdermal Patch As already mentioned earlier, details on the structure-performance correlation of the patch pre- pared via various processing routes have been re- ported elsewhere [29]. Here, we report briefly the structural characterization of the patch observed by optical imaging and scanning electron microscopy (SEM). The photograph of the transdermal patch prepared using CH and MC is shown in Figure 6a. The SEM analysis shows the surface morphology of the blank transdermal patch prepared using CH and MC (Figure 6b). Highly porous and uneven align- ment was observed which might be due to excess exposure to temperature during the drying process and water loss via evaporation while drying (Fig- ure 6). This kind of structural arrangement might be useful for the entrapment of active pharmaceuti- cal active ingredients (APIs) especially essential oils that are well-known for pain management or pain relief. While preparing the transdermal patches, the polymeric contents, a combination of plasticizers, and viscosity aid in fabricating uniform and consis- Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 127 tent structural configuration across the patch. This assessment not only ensures the adherence ability of the patch but also maintains the shelf life of the patch and the release of the drug at a controlled rate. Figure 6: Photograph (left) and SEM micrograph (right) showing the morphology of the transdermal patch prepared using CH and MC. 4 Conclusion This study has characterized the properties of the basic ingredients of a transdermal patch compris- ing chitosan (CH), methylcellulose (MC), and car- boxymethyl cellulose (CMC) to be enriched with wintergreen oil by different techniques such as SEM, IR, TGA, and rheological analyses. The SEM imaging of the biopolymers reveals distinct differences in their particle morphology. CH displays a smooth, non-porous, flake-like sur- face with larger granules compared to MC and CMC, which have fibrous structures and smaller particle sizes. CH's larger granules are likely due to its chitin base, while MC and CMC are derived from cellulose. All samples exhibit a broad FTIR band around 3400 cm−1, indicating the O-H stretching vibra- tions. CH and WG oil also show amine (NH2) and hydroxyl groups, while MC and CMC display cellulose-related features, as expected. WG oil re- veals aromatic and ester vibrations associated with the methyl salicylate. CH exhibits the lowest thermal stability, start- ing decomposition at lower temperatures, while CMC shows the highest stability, starting decompo- sition at higher temperatures and with less weight loss. MC has thermal stability similar to CH. All the biopolymers have thermal stability suitable for their use as transdermal patch fabrication. Future research will focus on optimizing biopolymer ratios and properties and essential oil selection to further advance the development of ef- fective patches for pharmaceutical applications. Acknowledgments Dipl. Laborchem. Petra Frank (Macromolecular Chemistry group, University of Siegen) is cordially thanked for her support during rheological measure- ments. We thank Prof. Ulrich Jonas for access to the equipment. We thank the German Academic Exchange Service (DAAD) for providing a research fellowship to PP in the frame of a binationally su- pervised PhD Project, the University Grants Com- mission for providing the PhD scholarship, and the University of Siegen for financial support. Authors Contribution PP: Performing experiments, analysis of results, drafting the first manuscript; EM: Analysis of re- sults, and interpretation; HS: Funding acquisition, conceptualization, supervision, and editing of the manuscript; RA: Co-drafting of manuscript, fund- ing acquisition, conceptualization,and supervision; AA: Supervision, and editing of the manuscript; RM: Supervision, data analysis and interpretation Conflict of Interest Statement The authors declare that they have no conflicts of interest. All the authors have read and approved the manuscript. References [1] M. Prausnitz and R. Langer. Transdermal drug delivery. Nature Biotechnology, 26(11):1261– 1268, 2008. [2] X. Zhan, Z. Mao, S. Chen, S. Chen, and L. Wang. Formulation and evaluation of trans- dermal drug-delivery system of isosorbide dini- trate. Brazilian Journal of Pharmaceutical Sci- ences, 51(2):1–9, 2015. [3] T. Karve, A. Dandekar, V. Agrahari, M. Melissa Peet, A. K. Banga, and G. F. Don- cel. Long-acting transdermal drug delivery for- mulations: Current developments and inno- vative pharmaceutical approaches. Advanced Drug Delivery Reviews, 210:115326, 2024. [4] C. Sun, N. Bu, and X. Hu. Recent trends in electronic skin for transdermal drug delivery. Intelligent Pharmacy, 1(4):183–191, 2023. [5] P. Krosuri, M. Reddy Dagada, G. Gurrappa- gari, G. Dakka, P. B. Reddy, and B. Bonala. Formulation and evaluation of pinacidil trans- dermal patches. Journal of Xidian University, 17(8):022, 2023. [6] V. Tyagi and Archana Thakur. Applications of biodegradable carboxymethyl cellulose-based composites. Results in Materials, 20:100481, 2023. Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 128 [7] M. Yanat and Karin Schroën. Preparation methods and applications of chitosan nanopar- ticles; with an outlook toward reinforcement of biodegradable packaging. Reactive and Func- tional Polymers, 161:104849, 2021. [8] R. K. Jani, G. K. Puri, G. S. Chakraborthy, N. Patel, D. Pooja, and V. J. Upadhye. Fabri- cation of transdermal matrix patch of lercani- dipine hydrochloride using natural polymer and essential oil. Journal of Pharmaceutical Research International, 34(12B):16–35, 2022. [9] S. Toraskar, V. Chakote, and P. Patil. Treat- ing fungal infections by herbal transdermal patches. In Techno-Societal 2022 (ICATSA 2022), 2023. [10] J. Baranwal, B. Barse, A. Fais, G. L. Delogu, and A. Kumar. Biopolymer: A sustainable ma- terial for food and medical applications. Poly- mers, 14(5):983, 2022. [11] B. Rajchal, Y. N. Thapa, D. Karki, P. Pra- japati, and R. Adhikari. Insights into electro- spun polymeric nanofiber mats: An innovative dressing for wound healing applications. Poly- mer International, 2024. [12] Md. Saifur Rahman, Md. Saif Hasan, A. S. Ni- tai, S. Nam, A. K. Karmakar, Md. Shameem Ahsan, Md. J. A. Shiddiky, and Md. Boshir Ahmed. Recent developments of car- boxymethyl cellulose. Polymers, 13(8):1345, 2021. [13] D. Elieh-Ali-Komi and M. R. Hamblin. Chitin and chitosan: Production and application of versatile biomedical nanomaterials. Interna- tional Journal of Advanced Research (Indore), 4(3):411–427, 2016. [14] Z. Shariatinia. Pharmaceutical applications of chitosan. Advances in Colloid and Interface Science, 263:131–194, 2019. [15] I. Aranaz, Andrés R. Alcántara, Maria Con- cepción Civera, Concepción Arias, Begoña Elorza, Angeles Heras Caballero, and Niuris Acosta. Chitosan: An overview of its proper- ties and applications. Polymers, 13(19):3256, 2021. [16] Y. Shen, F. Seidi, M. Ahmad, Y. Liu, Md. Reza Saeb, A. Akbari, and H. Xiao. Recent ad- vances in functional cellulose-based films with antimicrobial and antioxidant properties for food packaging. Journal of Agricultural and Food Chemistry, 71(44):16469–16487, 2023. [17] C. López de Dicastillo, F. Bustos, A. Guarda, and M. José Galotto. Cross-linked methyl cel- lulose films with murta fruit extract for antiox- idant and antimicrobial active food packaging. Food Hydrocolloids, 60:335–344, 2016. [18] S. Xia, H. Yu, Y. Qiu, Y. Zhao, H. Li, J. Zhang, and J. Zhu. A novel curdlan/methyl cellu- lose/walnut green husk polyphenol edible com- posite film for walnut packaging. Interna- tional Journal of Biological Macromolecules, 261(Part 1):129505, 2024. [19] S. Selvaraj, A. Chauhan, V. Dutta, R. Verma, S. K. Rao, A. Radhakrishnan, and S. Ghotekar. A state-of-the-art review on plant-derived cellulose-based green hydrogels and their multifunctional role in advanced biomedical applications. International Jour- nal of Biological Macromolecules, 265(Pt 2):130991, 2024. [20] W. Zhang, Y. Liu, Y. Xuan, and S. Zhang. Synthesis and applications of carboxymethyl cellulose hydrogels. Gels, 8(9):529, 2022. [21] M. Pourmadadi, E. Rahmani, A. Shamsabadipour, A. Samadi, J. Es- maeili, R. Arshad, A. Rahdar, F. Tavangarian, and S. Pandey. Novel carboxymethyl cellulose-based nanocomposite: A promis- ing biomaterial for biomedical applications. Process Biochemistry, 130:211–226, 2023. [22] C. B. Hollabaugh, L. H. Burt, and A. P. Walsh. Carboxymethylcellulose. uses and ap- plications. Industrial & Engineering Chem- istry, 37(10):943–947, 1945. [23] P. K. Ojha, D. K. Poudel, S. Dangol, A. Rokaya, S. Timsina, P. Satyal, and W. N. Setzer. Volatile constituent analysis of win- tergreen essential oil and comparison with synthetic methyl salicylate for authentication. Plants, 11(8):1090, 2022. [24] P. Michel and M. A. Olszewska. Phyto- chemistry and biological profile of Gaulthe- ria procumbens l. and wintergreen essential oil: From traditional application to molecu- lar mechanisms and therapeutic targets. In- ternational Journal of Molecular Sciences, 25(1):565, 2024. [25] B. Zhang, X-L. He, Y. Ding, and G.-H. Du. Gaultherin, a natural salicylate derivative from Gaultheria yunnanensis: Towards a better non-steroidal anti-inflammatory drug. Euro- pean Journal of Pharmacology, 530(1–2):166– 171, 2006. Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 129 [26] N. Morin-Crini, E. Lichtfouse, G. Torri, and G. Crini. Applications of chitosan in food, pharmaceuticals, medicine, cosmetics, agricul- ture, textiles, pulp and paper, biotechnology, and environmental chemistry. Environmental Chemistry Letters, 17:1667–1692, 2019. [27] W. F. de Oliveira, P. B. Sales Albuquerque, N. E. Ribeiro Rodrigues, P. M. dos Santos Silva, J. F. Kennedy, M. T. dos Santos Cor- reia, and L. C. B. Barroso Coelho. Pharmaceu- tical applications of chitosan on medical im- plants: A viable alternative for construction of new biomaterials? Carbohydrate Polymer Technologies and Applications, 7:100407, 2024. [28] J. Shokri and K. Adibkia. Application of cellu- lose and cellulose derivatives in pharmaceutical industries. In Cellulose. IntechOpen, 2013. [29] P. Panta, W. Chelangat, F. T. Shefat, A. Adhikari, R. Malla, H. Schönherr, and R. Adhikari. Development of chitosan- methylcellulose blend-based wintergreen oil in- fused transdermal patches via electrospinning. Macromolecular Symposia, 2025. Accepted. [30] S. Kumar and J. Koh. Physiochemical, optical and biological activity of chitosan-chromone derivative for biomedical applications. In- ternational Journal of Molecular Sciences, 13(5):6102–6116, 2012. [31] P. L. Nasatto, F. Pignon, J. L. Silveira, M. E. Duarte, M. D. Noseda, and M. Rin- audo. Methylcellulose, a cellulose derivative with original physical properties and extended applications. Polymers, 7(5):777–803, 2015. Accessed January 9, 2025. [32] H. S. Wahyuni, S. Yuliasmi, H. S. Aisyah, and D. Riati. Characterization of synthesized sodium carboxymethyl cellulose with variation of solvent mixture and alkali concentration. Open Access Macedonian Journal of Medical Sciences, 7(22):3878–3881, 2019. [33] M. M. Ibrahim, T. Y. A. Fahmy, E. I. Sala- heldin, F. Mobarak, M. A. Youssef, and M. R. Mabrook. Synthesis of tosylated and trimethylsilylated methyl cellulose as ph- sensitive carrier matrix. Life Science Journal, 12(1):29–37, 2015. [34] H. T.-T. Nguyen, T. N. Tran, A. C. Ha, and P. D. Huynh. Impact of deacetylation de- gree on properties of chitosan for formation of electrosprayed nanoparticles. Journal of Nan- otechnology, 2022. [35] R. D. Pratiwi, S. El Muttaqien, N. Gus- tini, N. S. Difa, G. Syahputra, and A. Rosyi- dah. Eco-friendly synthesis of chitosan and its medical application: From chitin extrac- tion to nanoparticle preparation. ADMET and DMPK, 11(4):435–55, 2023. [36] P. Severino, C. F. da Silva, M. A. da Silva, M. H. A. Santana, and E. B. Souto. Chitosan cross-linked pentasodium tripolyphosphate mi- cro/nanoparticles produced by ionotropic gela- tion. Sugar Technology, 16(1):77–83, 2014. [37] J. W. Rowen, C. M. Hunt, and E. K. Plyler. Absorption spectra in the detection of chemical changes in cellulose and cellulose derivatives. Textile Research Journal, 17(9):504–511, 1947. [38] Md. Ibrahim H. Mondal, Mst. Sarmina Yeas- min, and Md. Saifur Rahman. Preparation of food grade carboxymethyl cellulose from corn husk agrowaste. International Journal of Bio- logical Macromolecules, 79:144–150, 2015. [39] S. Mendes, A. Catarino, A. Zille, N. Fernandes, and F. M. Bezerra. Vehiculation of methyl sali- cylate from microcapsules supported on textile matrix. Materials, 14:1087, 2021. [40] M. El-Sakhawy, H. A. S. Tohamy, A. Salama, and S. Kamel. Thermal properties of car- boxymethyl cellulose acetate butyrate. Cellu- lose Chemistry and Technology, 53:65, 2019. [41] S. Sari, P. A. Soloman, and V. O. Rejini. Preparation of chitosan-cmc blends and stud- ies on thermal properties. Procedia Technology, 24:721–726, 2016. [42] J. Cui, J. Verma, and T. Emrick. Car- boxymethyl cellulose foams: fabrication, aque- ous stability, and water capture. Journal of Materials Sciences, 58:8230–8240, 2023. [43] S. Hiltunen, C. Xu, S. Willför, and K. Back- folk. Thermally induced degradation of nacmc in water and effects of nahco3 on acid forma- tion and charge. Food Hydrocolloids, 74:32–36, 2018. [44] B. Abu-Jdayil, M. Ghannam, K. A. Ahmed, and M. Djama. The effect of biopolymer chi- tosan on the rheology and stability of na- bentonite drilling mud. Polymers, 13(19):3361, 2021. [45] J. Desbrières, M. Hirrien, and S. B. Ross- Murphy. Thermogelation of methylcellu- lose: Rheological considerations. Polymer, 41(7):2451–2461, 2000. Prasamsha Panta et al./ BIBECHANA 22 (2025) 122-130 130 [46] R. Carpa, A. Farkas, C. Dobrota, and A. Butiuc-Keul. Double-network chitosan- based hydrogels with improved mechanical, conductive, antimicrobial, and antibiofouling properties. Gels, 9(4):278, 2023. [47] P. J. do Amaral Sobral, G. Gebremariam, F. Drudi, A. C. De Aguiar Saldanha Pin- heiro, S. Romani, and M. D. Rosa. Rheologi- cal and viscoelastic properties of chitosan solu- tions prepared with different chitosan or acetic acid concentrations. Foods, 11(17):2692, 2022. Introduction Materials and Methods Materials Characterization Methods Scanning Electron Microscopy (SEM) Analysis Fourier Transmission Infra-Red (FTIR) Spectroscopy Analysis Analysis (TGA) Rheological Measurement and Preparation of Patch Results and Discussion Morphology of Biopolymers Spectroscopic Characterization of Biopolymers and WG Oil Thermogravimetric Analyses of the Biopolymers Rheological Analysis of Biopolymers Structural Characterization of the Transdermal Patch Conclusion