Polysaccharide-coated liposomal formulations for dental targeting

Abstract

The efficacy of treatments of oral ailments is often challenged by a low residence time of the conventional pharmaceutical formulations in the oral cavity, which could be improved by using bioadhesive formulations. This in vitro study investigated charged liposomes, both uncoated and coated through electrostatic deposition with polysaccharides (chitosan, alginate and pectin), as bioadhesive systems for the oral cavity. First, formulations that provided liposomes fully coated with polysaccharide were selected. Thereafter, the stability of both the uncoated and the polysaccharide-coated liposomes was investigated in artificial saliva simulating pH, ionic strength, and ionic content of natural saliva. Additionally, adsorption to hydroxyapatite (model for tooth enamel) was tested. The surface charge was of high importance for both the stability in salivary environment and bioadhesion. In artificial saliva, the negatively charged liposomes were the most stable, and the stability of the positively charged liposomes was improved through coating with a negatively charged polysaccharide. On the contrary, the positively charged liposomes were the most bioadhesive, although a moderate adsorption was recorded for the negatively charged liposomes. Based on the present results, the negatively charged liposomes seem to be the most promising formulations used as a tooth adhesive nanosystem and could as such provide improved treatment of tooth ailments.

Micronutrients encapsulation in enhanced nanoliposomal carriers by a novel preparative technology

“…6 (for K2-loaded nanoliposomes). In general no aggregation among nanoliposomal structures (both uncoated and chitosan-coated) was observed, in agreement with the results obtained by, 39 demonstrating that negatively charged polysaccharide coated liposomes had more stability against aggregation.…”

Polymeric materials and films in dentistry: An overview

“…In fact, the use of charged liposomes, either uncoated or coated using electrostatic deposition with polysaccharides (alginate, chitosan and pectin), as bioadhesive systems for the oral cavity was investigated through an in vitro study ( Fig. 2 ) [23] . It was found that the liposome surface charge was highly important for their stability in saliva and for bioadhesion.…”

“…It was found that the liposome surface charge was highly important for their stability in saliva and for bioadhesion. The negatively charged liposomes were the most stable in artificial saliva, and the stability of the positively charged liposomes in the film was improved using a negatively charged polysaccharide [23] .

Fig.

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“…2 Pectin-coated liposomes that formed on tooth surfaces used as bioadhesive systems in the oral cavity. (Reproduced from Pistone et al [23] with permission from Elsevier). …”

Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

“…To increase the stability, both in vivo and in vitro, liposomes have been coated with polymers [10][11][12]. The polymers forming the coating may be attached to the liposomal surface by electrostatic deposition, e.g., chitosan [10,13,14], pectin [15,16], poly(N-isopropylacrylamide (PNIPAAM)-comethacrylic acid) [17], and alginate [18]. Charged polymer coatings have also been introduced for improving the mucoadhesive properties of the system [19][20][21] and for formulation of pH sensitive [22] and temperature sensitive delivery systems [23].…”