Cellulose derivatives and natural gums as gelling agents for preparation of emulgel-based dosage forms: A brief review

Incorporation of an emulsion onto a gel base develops a drug delivery system with improved characteristics, known as emulgel, that can envelop both hydrophilic and lipophilic molecules, and therefore increase stability and penetration of topical formulations. Such a drug delivery system provides controlled drug release that has more patient compliance and higher therapeutic efficacy. Emulgel is prepared in three main stages, preparation of water-in-oil or oil-in-water emulsion, providing the gel base, and incorporation of prepared emulsion onto gel base with continuous stirring. Various materials such as different oils (e.g. sesame oil, balsam oil, and mineral oil), emulsifiers (e.g. Tween® and Span® as the non-ionic surfactant, polyvinyl alcohol), and gelling agents including cellulose derivatives such as hydroxypropyl methylcellulose (HPMC), hydroxyethylcellulose (HEC) and carboxymethyl cellulose (CMC) in different concentrations are used in emulgel preparation. The physical properties, particle size distribution, spreadability, permeation, and drug release rate are evaluated in their development and characterization. They are used in skin disorders and other diseases such as chronic anal fisher. Also, anti-acne, analgesic, and anti-inflammatory drugs have been formulated as emulgel delivery system and their effects have been studied. In this article, the subject is to review the characteristics, preparation methods, and therapeutic efficacy as well as the potential clinical use of emulgels.

Evaluation of antioxidant potential of Heliotropium bacciferum Forssk extract and wound healing activity of its topical formulation in rat

Wound healing is a dynamic process that occurs in the tissue under the skin. During this process, oxidative stress biomarkers are excessively produced, which finally lead to inflammation and cellular damage. In this study, efforts have been made to evaluate the antioxidant effect and wound healing activity topical formulation containing Heliotropium bacciferum Forssk extract. The in vitro antioxidant properties were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities and the ferric reducing antioxidant power (FRAP) assay. The herbal ointments (2.5% w/w and 5% w/w) were prepared from the hydroalcoholic extract of H. bacciferum Forssk and administrated on the induced wounds in Wistar rats. The chromatic assay, percentage of wound contraction, and histopathological studies were used for evaluating the wound healing activity. For the evaluation of reactive oxygen species (ROS), catalase (CAT) activity, superoxide dismutase (SOD), and glutathione (GSH) levels were examined. The DPPH method showed tremendous radical scavenging activities at the corresponding concentrations with EC₅₀ value of 80μg/mL. Topical application of the ointment (5% w/w) showed the highest wound contraction in comparison to the positive control (treated with CICALFATE™) and the control group (treated with normal saline). Similarly, the histological study of the group treated with the extract ointment (5% w/w) showed full collagen tissue deposition with a complete epidermal regeneration. The results of the assessment of GSH levels as well as CAT and SOD activities in the treated group (5% w/w) confirmed the scavenging property of the extract ointment. Our findings indicated the proper wound healing impact of the topical formulation of H. bacciferum Forssk due to its notable antioxidant capacity.