Localized intra-periodontal pocket drug delivery using an injectable in situ forming gel is an effective periodontitis treatment. The aqueous insoluble property of rosin is suitable for preparing a solvent exchange-induced in situ forming gel. This study aims to investigate the role of incorporating lime peel oil (LO) on the physicochemical properties of injectable in situ forming gels based on rosin loaded with 5% w/w doxycycline hyclate (DH) in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP). Their gel formation, viscosity, injectability, mechanical properties, wettability, drug release, and antimicrobial activities were evaluated. The presence of LO slowed gel formation due to the loose precipitate formation of gel with a high LO content. The viscosity and injectability were slightly increased with higher LO content for the DH-loaded rosin-based in situ forming gel. The addition of 10% LO lowered gel hardness with higher adhesion. LO incorporation promoted a higher drug release pattern than the no oil-added formulation over 10 days and the gel formation rate related to burst drug release. The drug release kinetics followed the non-Fickian diffusion mechanism for oil-added formulations. LO exhibited high antimicrobial activity against Porphyromonas gingivalis and Staphylococcus aureus. The DH-loaded rosin in situ forming gel with an addition of LO (0, 2.5, 5, and 10% w/w) inhibited all tested microorganisms. Adding 10% LO to rosin-based in situ forming gel improved the antimicrobial activities, especially for the P. gingivalis and S. aureus. As a result, the study demonstrates the possibility of using an LO amount of less than 10% loading into a rosin-based in situ forming gel for efficient periodontitis treatment.

Localized delivery systems have been typically designed to enhance drug concentration at a target site and minimize systemic drug toxicity. A rosin/cinnamon oil (CO) in situ forming gel (ISG) was developed for the sustainable delivery of imatinib mesylate (IM) against colorectal cancer cells. CO has been claimed to express a potent anticancer effect against various cancer cells, as well as a synergistic effect with IM on colorectal cancer cells; however, poor aqueous solubility limits its application. The effect of rosin with the adding CO was assessed on physicochemical properties and in vitro drug release from developed IM-loaded rosin/CO-based ISG. Moreover, in vitro cytotoxicity tests were conducted against two colorectal cancer cells. All formulations exhibited Newtonian flow behavior with viscosity less than 266.9 cP with easier injectability. The adding of CO decreased the hardness and increased the adhesive force of the obtained rosin gel. The gel formation increased over time under microscopic observation. CO-added ISG had a particle-like gel appearance, and it promoted a higher release of IM over a period of 28 days. All tested ISG formulations revealed cytotoxicity against HCT-116 and HT-29 cell lines at different incubation times. Thus, CO-loaded rosin-based ISG can act as a potentially sustainable IM delivery system for chemotherapy against colorectal cancer cells.

The aim of this study was to prepare and characterize the imatinib mesylate (IM)-loaded gamboge-based ISG system for local administration of an anticancer agent against colorectal carcinoma. The ISG formulations were prepared in dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP). The physicochemical properties, drug release profile, and cytotoxicity of the developed formulations were assessed. The developed ISG demonstrated Newtonian flow behavior with acceptable rheological and mechanical properties. The viscosity of the developed ISG, measured at less than 80 cP, and the applied forces of less than 50 N·mm, indicated easy administration using clinical injection techniques. Upon contact with an aqueous phase, the ISG immediately formed a porous cross-sectional structure, enabling sustained release of IM over 14 days. The release profile of IM was fitted to the quasi-Fickian diffusion mechanism, and the release rate could be controlled by the types of solvent and the amount of IM content. The developed IM-loaded gamboge ISG effectively inhibited colorectal cancer cells, including HCT116 and HT29 cell lines, with less than 20% cell viability observed at a concentration of 1% w/w IM after 2 days of incubation. This suggests that the developed ISG may potentially serve as an injectable system for localized anticancer delivery against colorectal cells, potentially reducing the side effects of systemic chemotherapy and improving patient adherence.

Gambogic acid obtained from plant resin of Garcinia species has anticancer properties. This study focuses on the development and validation of the high-performance liquid chromatography (HPLC) method for the quantification of gambogic acid (GA) content in the gamboge raw sample. The chromatographic system was performed on C18 column (150 × 4.6 mm, 5 μm). The system consisted of acetonitrile and 0.1% orthophosphoric acid (85:15 v/v) as mobile phase with a flow rate of 1.5 mL/min. The detection was carried out at a wavelength of 360 nm and the retention time of GA was evident at 9 min. The method was validated according to ICH guidelines. The obtained calibration plot exhibited good linearity in the range of 5 to 120 μg/mL (r² > 0.999). The percentage recovery GA spiked in the gamboge sample ranged from 98.87% to 102.92%. The LOD and LOQ were shown to be 2.069 and 6.271 μg/mL, respectively. The validation study demonstrated that this method was simple, specific, and applicable for quantitative analysis of GA in gamboge resin.