A Clinical Trial: In Vivo Studies on Dexamethasone Sodium Phosphate Liposomes in the Treatment of Human Aphthous Stomatitis

Evolution of Drug Delivery Systems for Recurrent Aphthous Stomatitis

Recurrent aphthous stomatitis (RAS) is a disease marked by painful oral lesions on the buccal and labial mucosa or tongue. Drug delivery systems (DDS) for RAS include topical forms that manage wound healing, cover the ulcer, and relieve the associated pain. DDS targeting the oral mucosa face a major challenge, especially the short residence times in the mouth due to the effect of “saliva wash-out”, which continually removes the drug. The objective of this review is to study the development of preparation forms and delivery systems of various types and preparations that have been used for RAS management from 1965 until February 2020. There are 20 types of DDS for RAS which were discussed in 62 articles. The preparations were classified into 4 preparation forms: liquid, semi-solid, solid, and miscellaneous. In addition, the ultimate DDS for RAS preparations is the semi-solid forms (41.94%), which include 5 types of DDS are gel, paste, patch, cream, and ointment. This preparation was developed into new preparation form (11.29%), such as adhesive alginates, dentifrice, OraDisc, membranes, bioresorbable plates, pellicles, and gelosomes. Generally, the mucosal drug delivery system is the method of choice in RAS treatment because the ulcer is commonly located in the oral mucosa. In conclusion, these preparations are designed to improve drug delivery and drug activity for the treatment of RAS ulcers. Moreover, almost all of these DDS are topical preparations that use various types of mucoadhesive polymers to increase both residence time in the oral mucosa and pain relief in RAS treatment.

Gamma-irradiated liposome/noisome and lipogelosome/niogelosome formulations for the treatment of rheumatoid arthritis

Treatment of rheumatoid arthritis by intraarticular administration of anti-inflammatory drugs encapsulated in drug delivery systems, such as liposomes/niosomes and lipogelosomes/niogelosomes, prolongs the residence time of the drugs in the joint. It was therefore anticipated that liposome/niosome entrapment would enhance the efficacy of drugs in the inflammatory sides. Liposomes are good candidates for the local delivery of therapeutic agents, such as diclofenac sodium (DFNa), for intraarticular delivery. Drugs for parenteral delivery must be sterile, and radiation sterilization is a method recognized by pharmacopoeias to achieve sterility of drugs. However, irradiation might also affect the performance of drug delivery systems. One of the most critical points is irradiation dose, because certain undesirable chemical and physical changes may accompany with the treatment, especially with the traditionally applied dose of 25 kGy. The present study aims to determine the effects of gamma irradiation on DFNa-loaded liposomes/niosomes and lipogelosomes/niogelosomes for the treatment of rheumatoid arthritis.

The influence of liposomal formulation factors on the interactions between liposomes and hydroxyapatite

Liposomes may have potentials as a drug delivery system in the oral cavity; hence, the adsorption to, oral tissues may be of importance. The aim of this study was to find an optimal liposomal formulation with appropriate in vitro stability and which liposomal formulation parameters may be of importance for the interaction to tooth enamel surfaces. Charged liposomes were adsorbed in vitro onto hydroxyapatite (HA), used as a model substance for human dental enamel. For a systematic approach of lipid selection, statistical experimental design and multivariate analysis were conducted to interpret the data. The factors investigated were the type of charge (positive, negative), type of main phospholipid (egg-PC, DPPC, DMPC), type of charged lipid (diacyl-TAP, -ethylPC, -PA, -PG, -PS), the amount of charged component (2.5, 10mol%) and the inclusion of cholesterol in the lipid bilayer. The results indicated that positively charged liposomes expressed significantly higher adsorption levels than the negatively charged ones. The effect of incorporating cholesterol did not turn out to be significant. Both positive egg-PC and DPPC liposomes exhibited high adsorption levels; however egg-PC liposomes were unstable during storage. For positively charged liposomes, the factor "type of main lipid" was found to be of significance for the adsorption, whereas, for negatively charged liposomes, no such important factors were found. Based on the adsorption profile to HA and the in vitro stability in phosphate buffer, the most promising liposomal formulation to target for human enamel in this study was the positively charged DPPC liposomes with 10mol% charged lipid included. However, more experiments are needed to determine the optimum mol% of positively charged lipid for the adsorption onto HA.