Abstract

FORMULATION AND EVALUATION OF ACYCLOVIR AND CHLORHEXIDINE ORAL EMULGEL AS NOVEL DRUG DELIVERY SYSTEMS

Mahmoud Mahyoob Alburyhi*, Abdalwali Ahmed Saif, Maged Alwan Noman

Abstract

Background: Oral herpes is a common, recurrent condition marked by painful mucosal lesions and risk of secondary bacterial infections. Conventional topical treatments suffer from poor mucosal retention, low drug penetration, and limited patient compliance. Emulgels, combining the hydrophilic properties of gels with the biphasic structure of emulsions, offer enhanced solubility, stability, controlled release, and mucosal penetration. Additionally, Gels further offer ease of application, high spreadability, and good patient acceptability. Clove oil, a natural analgesic, anti-inflammatory, and antimicrobial agent, also improves taste, promoting better compliance. Methods: Eleven formulations of oral gels and Emulgels were developed using Carbopol 974, Xanthan Gum, and HPMC as gelling agents. Methylparaben and propylparaben served as preservatives, while propylene glycol, glycerin, sucralose, triethanolamine, and Tween were included as excipients for stability and patient-friendly characteristics. Strawberry flavor was also used in gel formulation to enhance sensory appeal. Acyclovir (antiviral), chlorhexidine (antimicrobial), and clove oil as a multifunctional additive. Formulations were evaluated for physicochemical properties, viscosity, spreadability, mucoadhesive strength, drug content, swelling index, microbial contamination, and storage stability. A mucosal irritation test was also performed to assess safety and tolerability of the formulas upon application. Results: Gel formulation F5 exhibited optimal viscosity, spreadability, and mucoadhesive strength among the gel group and was flavored with strawberry for enhanced acceptability. Emulgel formulations F10 and F11 showed superior viscosity and muco-adhesion, along with better spreadability. Drug content was consistently high: Acyclovir was 99.5% for F5 (Acyclovir), 99.8% for F10 and F11 (Acyclovir), and 98.7% and 99.05% for F10 and F11 (Chlorhexidine), respectively. Microbial testing confirmed the sterility of key formulations (F5, F10, and F11), and all maintained physical and chemical stability over time. Sensory evaluation revealed improved taste and patient acceptability in clove oil and flavored formulations. Conclusion: The optimized Oral Emulgel formulation, containing a combination of Acyclovir, Chlorhexidine, and clove oil, represents a promising and effective approach for managing oral herpes. It offers dual antiviral and antimicrobial activity, enhanced muco-adhesion, and improved sensory qualities, including taste and texture. The inclusion of a tri-polymer base significantly contributes to the rheological performance and stability of the formulation. These attributes support better patient comfort, compliance, and therapeutic outcomes while minimizing systemic side effects and irritation common in oral drug delivery. It was concluded that the best gel Formulations F5 and Emulgel F11 were found to be optimal viscosity, spreadability, percent of drug content were 99.5%, 99.05%, and mucoadhesive strength among the Acyclovir gels formulations NDDS and a combination of Acyclovir and Chlorhexidine Emulgels formulations NDDS respectively. Formulation scientist from his experience and knowledge have to significantly in the preformulation study stage and is an important factor in the ADDS (Advanced Drug Delivery Systems) product development process.

Keywords: Acyclovir, Antiviral, Chlorhexidine, Antimicrobial, NDDS, Formulation, Excipients, Development, Gel, Emulgels.