hydroxyethylcellulose and carboxypolymethylene

It was the aim of this study to assess in vitro methods for the characterization of mucoadhesive hydrogels for their potential to predict the residence time on human buccal mucosa.. Mixtures of hydrogels comprising hydroxyethyl cellulose (HEC), sodium carboxymethyl cellulose (CMC), xanthan gum (XTGM), hyaluronic acid sodium salt (HA), sodium alginate (ALG), carbopol (CP) as well as polycarbophil (PCP) and porcine mucus were analysed for relative rheological synergism. Furthermore, hydrogels were characterized for their texture and mechanical properties. For the assessment of mucoadhesive strength of formulations tensile studies were performed on porcine buccal mucosa. To facilitate a direct comparability of data the residence time of stained hydrogels was determined ex vivo on porcine buccal mucosa and in the oral cavity of volunteers.. The extent of relative rheological synergism was in good agreement with data from in vivo residence time studies. Results of tensile studies were further effected by textural properties of hydrogels leading to a restricted correlation with data from the in vivo experiment. The resistance towards removal by artificial saliva flow ex vivo revealed the highest correlation to the in vivo experiment with increasing mucosal residence time in the rank order CP < HEC, HA, ALG, PCP < CMC < XTGM.. This overview of measurement principles to predict the residence time of hydrogels for buccal application in humans may be a potent tool for the development of semisolid intraoral formulations.

Topics: Acrylic Resins; Adhesives; Administration, Buccal; Adult; Alginates; Animals; Carboxymethylcellulose Sodium; Cellulose; Correlation of Data; Drug Compounding; Drug Delivery Systems; Humans; Hyaluronic Acid; Hydrogels; In Vitro Techniques; Mouth; Mouth Mucosa; Polysaccharides, Bacterial; Swine; Young Adult

The development of drugs that can be used as topical microbicides is currently recognized as a priority area of research.. A preclinical evaluation of the potential effectiveness of TMC120, a non-nucleoside reverse transcriptase inhibitor (NNRTI), as a topical microbicide to prevent vaginal HIV-1 transmission in a humanized severe combined immunodeficient (hu-SCID) mouse model.. Reconstituted mice received an intravaginal application of a TMC120-containing gel 20 min prior to a non-invasive vaginal challenge with cell-associated HIV. The possible cytotoxic effect of TMC120-containing-gel on lymphocytes was assessed and their in vivo migration was followed using fluorescently labelled human lymphocytes. Systemic infection was monitored by p24 antigen detection in culture supernatant from cocultured intraperitoneal cells using antigen capture enzyme-linked immunosorbent assay test and by the presence of integrated proviral HIV-1 DNA in DNA extracted from spleen cells. In vivo migration of labelled lymphocytes was examined by analysis of cells isolated from regional lymph nodes.. In this model, systemic infection was successfully inhibited by the presence of TMC120-containing gel at vaginal level. The in vivo migration of human lymphocytes from the vagina to regional lymph nodes, following the deposition of TMC120-containing gel, excluded the possibility that inhibition of systemic infection was a result of NNRTI toxicity.. Vaginal transmission of HIV was successfully prevented by the application of a gel formulation containing TMC120. This is the first evidence of the in vivo effectiveness of a microbicide preparation containing an NNRTI against cell-associated HIV.

Topics: Acrylic Resins; Administration, Intravaginal; Animals; Anti-Infective Agents; Cellulose; Female; Gels; HIV Infections; HIV-1; Lymphocytes; Mice; Mice, SCID; Polyvinyls; Reverse Transcriptase Inhibitors; Vagina; Viscosity

The combination of benzoyl peroxide and erythromycin is used for the local treatment of acne and available as a commercial preparation. Because of the stability problems of erythromycin an extempore preparation is required. The influence of storage temperature and non active ingredients on the stability of benzoyl peroxide and erythromycin in topical gel preparations for extempore compounding is described. A microbiological and an HPLC method were used to determine the erythromycin and the benzoyl peroxide concentrations, respectively. For a formulation compounded with hydroxyethylcellulose no stability problems were observed. For the formulation containing Carbopol 940, the levels of erythromycin varied over a wide range due to precipitation and aggregation of the drug during compounding.

Topics: Acrylic Resins; Administration, Topical; Anti-Bacterial Agents; Benzoyl Peroxide; Cellulose; Chemical Precipitation; Chemistry, Pharmaceutical; Chromatography, High Pressure Liquid; Drug Interactions; Drug Stability; Erythromycin; Excipients; Gels; Keratolytic Agents; Microbiological Techniques; Polyvinyls; Temperature