Sylva Holešová

Preparation of novel organovermiculites with antibacterial activity using chlorhexidine diacetate.

The novel antibacterial organovermiculites with different mass ratios of chlorhexidine diacetate (CA) were successfully prepared by ion exchange reactions. The resultant organovermiculites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal properties of prepared organovermiculites were investigated by simultaneous thermogravimetry (TG) and differential thermal analysis (DTA). The antibacterial activity of prepared organovermiculites against Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding minimum inhibitory concentration (MIC). Antibacterial studies showed that the organovermiculites strongly inhibited the growth of variety of microorganisms.

Carmellose Mucoadhesive Oral Films Containing Vermiculite/Chlorhexidine Nanocomposites as Innovative Biomaterials for Treatment of Oral Infections

Infectious stomatitis represents the most common oral cavity ailments. Current therapy is insufficiently effective because of the short residence time of topical liquid or semisolid medical formulations. An innovative application form based on bioadhesive polymers featuring prolonged residence time on the oral mucosa may be a solution to this challenge. This formulation consists of a mucoadhesive oral film with incorporated nanocomposite biomaterial that is able to release the drug directly at the target area. This study describes the unique approach of preparing mucoadhesive oral films from carmellose with incorporating a nanotechnologically modified clay mineral intercalated with chlorhexidine. The multivariate data analysis was employed to evaluate the influence of the formulation and process variables on the properties of the medical preparation. This evaluation was complemented by testing the antimicrobial and antimycotic activity of prepared films with the aim of finding the most suitable composition for clinical application. Generally, the best results were obtained with sample containing 20 mg of chlorhexidine diacetate carried by vermiculite, with carmellose in the form of nonwoven textile in its structure. In addition to its promising physicomechanical, chemical, and mucoadhesive properties, the formulation inhibited the growth of Staphylococcus and Candida; the effect was prolonged for tens of hours.

Antibacterial efficiency of vermiculite/chlorhexidine nanocomposites and results of the in vivo test of harmlessness of vermiculite

Clay minerals have been proposed as very useful materials for modulating drug delivery. These are the commonly used materials in pharmaceutical production both as inorganic carriers or active agents. We focused on the development of suitable long-acting material for local treatment of oral infection where clay minerals act as inorganic drug carriers. Organovermiculites with antibacterial activity were prepared by ion exchange reactions using different concentrations of chlorhexidine diacetate. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TGA). The antibacterial activity was evaluated by finding the minimum inhibitory concentration (MIC). All studied organoclays possessed good antibacterial activity after 24h exposure against Escherichia coli, Enterococcus faecalis and particularly against Staphylococcus aureus. Pseudomonas aeruginosa however proved very resistant as only the sample with the highest concentration of CA that successfully inhibited bacterial growth. Furthermore, clay mineral vermiculite was subjected to in vivo toxicological analysis and its influence on gastrointestinal tract during its oral application was investigated. Tissue samples from buccal mucosa, tongue, esophagus, stomach, terminal duodenum, small intestine, caecum, distal colon and liver were subjected to histological examination, both macroscopically and microscopically. Neither systemic nor local reactions were observed. Therefore the toxicity of vermiculite to a mammal model organism can be excluded.