Evaluation of Fluoride Release in Chitosan-Modified Glass Ionomer Cements.

OBJECTIVE: This study assessed the influence of chitosan nanoparticles on the fluoride-releasing ability of 4 glass ionomer cement (GIC) through an in vitro analysis. METHODS: Four types of GIC (type II light cure universal restorative, type II universal restorative, GC Fuji VII, and type IX) were modified with nanochitosan particles; 10% chitosan was added to the glass ionomer liquid. Six specimens for each of the 4 groups were created, using expendable Teflon moulds. Discs of each type of GIC (n = 6) were immersed in deionised water at various time intervals. Electrodes selective for fluoride ions were employed to analyse the amount of released fluoride at 1, 7, 14, 21, and 28 days. RESULTS: Chitosan-modified GICs showed greater fluoride release than conventional GICs at all time points. All samples showed an initial high release of fluoride that tapered off with time. The total amount of fluoride released increased from the 1st day to the 28th day on adding chitosan to all the 4 types of GIC. Amongst those, type IX high-strength posterior extra with chitosan released a considerably higher quantity of fluoride at all time intervals. CONCLUSIONS: In all the experimental groups, adding chitosan to the glass ionomer liquid had an accelerating effect on its fluoride-releasing property.

Biosynthesis of Gold and Silver Nanoparticles Using Extracts of Callus Cultures of Pumpkin (Cucurbita maxima).

The potential of callus cultures and field-grown organs of pumpkin (Cucurbita maxima) for the biosynthesis of nanoparticles of the noble metals gold and silver has been investigated. Biosynthesis of AuNPs (gold nanoparticles) and AgNPs (silver nanoparticles) was obtained with flowers of C. maxima but not with pulp and seeds. With callus cultures established in MS-based medium the biogenesis of both AuNPs and AgNPs could be obtained. At 65 °C the biogenesis of AuNPs and AgNPs by callus extracts was enhanced. The AuNPs and AgNPs have been characterized by UV-visible spectroscopy, TEM, DLS and XRD. Well-dispersed nanoparticles, which exhibited a remarkable diversity in size and shape, could be visualized by TEM. Gold nanoparticles were found to be of various shapes, viz., rods, triangles, star-shaped particles, spheres, hexagons, bipyramids, discoid particles, nanotrapezoids, prisms, cuboids. Silver nanoparticles were also of diverse shapes, viz., discoid, spherical, elliptical, triangle-like, belt-like, rod-shaped forms and cuboids. EDX analysis indicated that the AuNPs and AgNPs had a high degree of purity. The surface charges of the generated AuNPs and AgNPs were highly negative as indicated by zeta potential measurements. The AuNPs and AgNPs exhibited remarkable stability in solution for more than four months. FTIR studies indicated that biomolecules in the callus extracts were associated with the biosynthesis and stabilisation of the nanoparticles. The synthesized AgNPs could catalyse degradation of methylene blue and exhibited anti-bacterial activity against E. coli DH5α. There is no earlier report of the biosynthesis of nanoparticles by this plant species. Callus cultures of Cucurbita maxima are effective alternative resources of biomass for synthesis of nanoparticles.

Biogenic synthesis of gold and silver nanoparticles by seed plants.

Nanoparticles have an enormous range of biomedical and environmental applications and can be used for development of various nanodevices for diagnostics and drug delivery. Biogenic production of nanoparticles, that is of silver and gold, by seed plants, especially flowering plants, has evoked considerable interest in the last decade. Different organs of plants as well as callus cultures have been used for the production of these metal nanoparticles. It is possible to regulate the geometry of the nanoparticles by modifying the experimental parameters. In many cases the phytosynthesized gold and silver nanoparticles have been demonstrated to be potentially useful for treatment of various diseases. The production of gold and silver nanoparticles by diverse species of seed plants and their biological activity are discussed in this article.

Design, evaluation and in vitro - in vivo correlation of glibenclamide buccoadhesive films.

BACKGROUND: Glibenclamide (G) is a popular anti-diabetic drug, belonging to the class of sulfonylurea. The drug is widely used for treating type II diabetes but it undergoes first-pass effect. A novel aspiration in treatment of diabetes, to provide greater therapeutic effect, bypass first pass effect and to improve patient compliance upon administering buccal drug delivery of Glibenclamide (G) have not been tested literally. Hence, the present study was designed to develop the buccal mucoadhesive films of glibenclamide by solvent casting technique; that is by using different polymers such as Hydroxy Propyl Methyl Cellulose 15 cps (HPMC), carbopol (CP), and poly vinyl pyrrolidone. Propylene glycol, which served the purpose of plasticizer as well as penetration enhancer and the backing membrane used was aluminium foil. MATERIALS AND METHODS: The films were subjected to physicochemical parameters, in-vitro drug release and ex vivo bucco adhesive strength. RESULTS: The satisfactory results were obtained in all prepared formulation and based on the results G14 [HPMC (150 mg) + CP(20 mg) + PVP (30 mg)] was the best one compared to others. The drug release of all formulation follows zero order kinetics by diffusion mechanism of non-fickian diffusion type. Ex vivo, buccal permeation studies by using sheep buccal mucosa and finally stability studies by using human saliva were carried out for the optimized formulation G14.Good correlation was observed between in-vitro and in vivo correlation, thus revealing the ability of the formulation to reproduce the in-vitro release pattern through the in vivo. CONCLUSION: Glibenclamide muck-adhesive buccal films could be promising one as they, increase bioavailability by bypassing the first pass effect, minimize the dose, reduces the side effects, and improve patient compliance and also glibenclamide might be a right and suitable candidate for oral controlled drug delivery via buccoadhesive films.

Formulation and evaluation of bucco-adhesive tablets of sumatriptan succinate.

BACKGROUND: A novel aspiration in treatment of migraine, to provide greater therapeutic effect, overcome the side effects by complex therapeutic regimen and to improve patient compliance upon administering bucco-adhesive tablet formulations of sumatriptan succinate which have not been tested literally. MATERIALS AND METHODS: This study was designed to develop a bucco-adhesive tablet containing sumatriptan succinate using blends of different bio-adhesive polymeric combinations such as hydroxy propyl methyl cellulose K4M, sodium carboxy methyl cellulose, and Carbopol 934P with a backing layer of ethyl cellulose by a direct compression technique. Tablets were subjected to physico-chemical parameters, swelling index, surface pH, ex vivo bioadhesive force, in vitro drug release, ex vivo drug permeation, and stability in saliva. RESULTS: Good results were obtained in all the evaluated parameters. The drug release of all formulation follows zero-order kinetics by a diffusion mechanism type. Stability studies in human saliva, ex vivo buccal permeation studies by using sheep and porcine buccal mucosa were carried out for the optimized formulation (S4 CP:HPMC 3:1). CONCLUSION: The developed buccal drug delivery system containing sumatriptan succinate might be the alternative routes available to bypass the first pass metabolism and might be a milestone in the therapy of migraine and among all formulations S4 shows good controlled release results correlated with ex vivo permeation studies.