Hoang Nhan Ho

Background: Tinidazole (TNZ) demonstrates greater efficacy against anaerobic bacteria, particularly Gram-negative strains, compared to metronidazole. Nanosizing TNZ and incorporating it into in situ gel formulations for topical periodontitis treatment offers several advantages. Objectives: This study aimed to formulate an in situ gel containing preformed Eudragit RSPO-based nanoparticles (NPs) of TNZ and to evaluate its physicochemical properties. Materials and methods: Poloxamer 407 was used as a thermosensitive gelling agent, either alone or in combination with other gelling agents. The in situ gels containing TNZ NPs were prepared and evaluated for physicochemical properties. Results: The in situ gel containing TNZ NPs, formulated with Poloxamer 407 and sodium alginate, exhibited a smooth texture, a gelation temperature of 31.33 ± 0.24 °C, a gelation time of less than one minute, a pH of 6.72 ± 0.03, and a stable gel state over an extended period. Compared to the in situ gel with TNZ material, the TNZ NP-loaded gel prolonged drug release. The drug release mechanism was best described by the Higuchi model (with F0). Conclusion: This TNZ NP-loaded in situ gel formulation shows promise for further research in periodontitis treatment.

This article previously published in Volume 22 Issue 6 of this journal in June 2023 has been retracted in line with the guidelines from the Committee on Publication Ethics (COPE, http://publicationethics.org /resources /guidelines). This was a follow up to the report by somebody identified as VU Nguyen (email: nguyenvu81@protonmail.com) of the duplicate publication of an article earlier published in 2020 (available at http://125.212.201.8:6008 / ViewOnline?bitstid=0d585588-2d02-4839-907a-92998674bb4d & type=1) in Vietnamese where a figure and some text in the article were repeated in the article published in this journal. This action was taken after thorough investigation of the plagiarism report and follow-up comments from both the corresponding author and Nguyen VU against the guidelines of the Committee on Publication Ethics (COPE). Retraction: Ho HN, Nguyen VA, Ho NA, Le HH. Development of a hydrogel containing metronidazole-loaded Eudragit RS 100 nanoparticles for buccal drug delivery. Trop J Pharm Res 2023; 22(6):1147- 1154 doi: 10.4314/tjpr.v22i6.1.

Curcumin (CUR) is a natural compound extracted from turmeric (Curcuma longa L.) used to cure acne, wound healing, etc. Its disadvantages, such as poor solubility and permeability, limit its efficacy. Nanoemulsion (NE)-based drug delivery systems have gained popularity due to their advantages. This study aimed to optimize a CUR-NE-based gel and evaluate its physicochemical and biological properties. A NE was prepared using the catastrophic phase inversion method and optimized using the Design Expert 12.0 software. The CUR-NE gel was characterized in terms of visual appearance, pH, drug release, antibacterial and wound healing effects. The optimal formulation contained CUR, Capryol 90 (oil), Labrasol:Cremophor RH40 (1:1) (surfactants), propylene glycol (co-surfactant), and water. The NE had a droplet size of 22.87 nm and a polydispersity index of 0.348. The obtained CUR-NE gel had a soft, smooth texture and a pH of 5.34 ± 0.05. The in vitro release of CUR from the NE-based gel was higher than that from a commercial gel with nanosized CUR (21.68 ± 1.25 µg/cm², 13.62 ± 1.63 µg/cm² after 10 h, respectively). The CUR-NE gel accelerated in vitro antibacterial and in vivo wound healing activities as compared to other CUR-loaded gels. The CUR-NE gel has potential for transdermal applications.

Purpose: To formulate Eudragit RS 100-based nanoparticles containing metronidazole (MTZ NPs) and incorporate them into hydrogels using different gelling agents for controlled release in the buccal mucosa. Method: MTZ NPs were fabricated using the nanoprecipitation method. MTZ NPs (1 % w/w) were introduced into hydrogels using different gelling excipients. Physicochemical properties of MTZ NPs, mucoadhesive strength and spreadability of the hydrogels, and ex vivo permeation of MTZ were evaluated. Results: MTZ NPs were spherical in shape and had a mean particle size of 201.9 ± 5.6 nm, polydispersity index (PDI) of 0.092 ± 0.014, and encapsulation efficiency of 46.28 ± 1.18 %. Hydroxyethyl cellulose (HEC) hydrogel containing MTZ NPs showed homogenous and smooth appearance, mucoadhesive strength of 2789.7 ± 13.4 dyne/cm² , and spreadability of 5.32 ± 0.77 cm. The cumulative amount of drug permeated from MTZ hydrogel and MTZ-containing NP hydrogel through porcine buccal mucosa was 1104.33 ± 28.97 and 397.62 ± 16.13 µg/cm² , respectively, after 7 h (p < 0.05). Conclusion: HEC hydrogel containing MTZ NPs demonstrates high mucoadhesive strength, good spreadability, and sustained ex vivo permeation of MTZ. Thus, HEC hydrogel is a promising pharmaceutical formulation for controlled drug release in the buccal mucosa

Background: Clotrimazole (CLO) is a widely used drug for the treatment of cutaneous and mucosal fungal infections caused by Candida albicans (C. albicans). To improve the topical drug absorption, nano-sized drug delivery systems have gained significant attention, particularly for poorly soluble drugs such as CLO. This research aimed to assess the drug release capability of gel containing clotrimazole-loaded nanoparticles and evaluate its antifungal activity against C. albicans. Materials and methods: CLO (China), Eudragit RS100 (Germany), Carbopol 934P (China), and other chemicals were utilized in this study. The clotrimazole-loaded nanoparticles were prepared and incorporated into the gel formulation. The in vitro drug release profile of gel was evaluated using Franz diffusion cells. Furthermore, the antifungal efficacy against C. albicans was assessed using Potato Dextrose Agar (PDA) medium. Results: The prepared gel containing CLO-loaded nanoparticles were stable during 6-week storage, demonstrated prolonged drug release after 24 hours compared to the gel containing free CLO (51.46 ± 1.10% and 71.98 ± 1.40%, respectively), exhibited better antifungal activity against C. albicans than gel containing free CLO (31 points versus 33 points). Conclusion: The CLO-loaded nanoparticles incorporated into the gel formulation showed promising potential as a topical drug delivery system, enhancing the antifungal activity and prolonging the drug release.

Background: According to the WHO's recommendations, hand washing is one of the most important ways to interrupt the transmission of infectious diseases. However, fast-acting hand sanitizers on the market are mainly composed of synthetic moisturizing agents, with very little combination of natural moisturizing ingredients such as Aloe vera (A. vera) extract from the Aloe plant. A. vera is a benign ingredient with effective moisturizing and antioxidant properties, making it ideal for supplementing moisturizing agents in gel products. Therefore, the study aimed to develop a formula for a fast hand sanitizer gel combining supplemented with A. vera as a moisturizing ingredient and to evaluate several characteristics of the resulting gel. Materials and methods: A. vera leaves, Carbopol 940, ethanol were used. The study involved investigating the concentration of the gelling excipient to create a favorable gel formulation. The hand sanitizer gel was evaluated for several physicochemical properties and antimicrobial efficacy. Results: The formula containing 15% A. vera (w/w), 65% ethanol, 1.5% Carbopol 940, 5% propylene glycol, and 0.8% triethanolamine met the quality specification and demonstrated antimicrobial activity against Escherichia coli and Staphylococcus aureus. Conclusion: The study successfully developed a antibacterial hand sanitizer gel supplemented with A. vera as moisturizers.

Fungal infection of the skin is one of the most common dermatological diseases in the world. Gel formulations are among the most suitable dosage forms for topical use to treat cutaneous infection. Nanotechnology is a promising approach to penetrate the deeper skin layers and enhance permeability of itraconazole (ITZ) through the stratum corneum. ITZ-loaded nanoparticles (ITZ NPs) were fabricated using the evaporation emulsion method, followed by incorporation of NPs into gel using Carbopol 934 as the gel-forming excipient. The physical properties, in vitro release, ex vivo permeation studies, and antifungal activity of ITZ NP gel were characterized. ITZ NPs were almost spherical in shape with colloidal sizes in the range of 200 nm. The drug encapsulation efficiency was %. ITZ NP gel demonstrated a sustained ex vivo permeation of ITZ over 24 h through excised rat skin and a higher drug penetrating capacity than that of a gel containing ITZ-saturated suspension. The in vitro antifungal activity of the ITZ-loaded NP incorporated gel was better than that of ITZ dispersion. Incorporation of the ITZ-loaded nanosystem into gel has the potential to enhance antifungal activity through transdermal drug delivery.