FORMULATION AND EVALUATION OF MATRIX DIFFUSION CONTROLLED TRANSDERMAL DRUG DELIVERY SYSTEM OF GLIPIZIDE

Abstract: Context: There has been a tremendous increase in interest for transdermal drug delivery system for sustain release dosage form in chronic manageable diseased conditions like diabetes, hypertension etc to reduce the frequency of dosing. It reduces the risk of exposing the body to drug above maximum safe concentration in case of dosage form failure in comparison to oral sustained release drug delivery system. Aims: Transdermal patches of Glipizide were formulated to achieve sustain release pattern within the therapeutic range. Methods and Material: HPMC 5cps, HPMC 15cps, HPMC K-100M, Ethyl cellulose (EC), Eudragit RS 100 (ERS-100) and Polyvinylpyrrolidone (PVP) K30 were used as matrix forming polymer. Propylene glycol was used as penetration enhancer. Polyethylene glycol (PEG) 400 and n-dibultyl phthalate (n-DB) were used as plasticizer. Methanol and chloroform were used as solvents. Patches were prepared by solvent casting method. Results: Patches prepared, from each batch, gave release profile for over 10 hours. Conclusions: Prepared patches from HPMC 5 cps and ethyl cellulose exhibited good characteristics for sustained release action and other parameters evaluated

Microhardness studies on Bi-In single crystal

359-364Microhardness measurements (Vicker 's hardness number) and x- ray studies have been performed on , surface in trigonal plane (111) on single crystal specimens of pure Bi and Bi doped with 4 at. % of  In at room temperature. Vicker's hardness number of Bi -In system is less compared to pure Bi, otherwise a brittle metal, ductile by adding a small quantity of In, which will add to its metallurgical and industrial applications. Further, the Vicker 's hardness number is found to be constant along the surface of Bi-In system, implying presence of a uniform phase in it. This suggests that In makes complete solid solution with Bi. The size of atomic radius of In seems to favour substitutional solid solution, where the dopant atoms occupy the sites on the parent atoms and effectively alter the periodicity of  Bloch potential and modify the band structure of  Bi. Presence of any other phase is not revealed in x-ray diffraction pattern of the Bi- In system and this confirms that the lattice of the doped system is essentially that of bismuth. Cohen's analytical method of least squares refinement for cubic crystals is modified for a hexagonal lattice and employ to calculate the lattice parameters of Bi and Bi -In system . An expansion of the unit cell is reported on account of doping. Laue back –reflection photographs show that 3 -fold symmetry of pure bismuth lattice is retained after doping.</span

Microhardness and X-ray studies of single crystals of Bi doped with group IV elements, Pb and Ge

59-64Microhardness tests and X-ray studies performed on single crystals of pure Bi, Bi-Pb (3at.%) and Bi-Ge (2at.%) in trigonal direction [111] at room temperature reveal quite contrasting features for Pb and Ge as dopants, despite the fact that both of these belong to group IV of periodic table of elements. It is reported that Pb has a hardening effect on the bismuth lattice, whereas Ge has softening effect on bismuth lattice. This result may find many metallu rgical and industrial applications. The Vicker's hardness number increased to a value of 13.9 for Bi-Pb system, whereas it decreased to a value of 11.8 for Bi-Ge system, compared to a value of 12.4 for pure Bi. Microhardness tests and X-ray studies indicate Pb and Ge make predominantly a solid solution with bismuth by substituting for Bi atoms at various lattice sites with small discontinuous traces of second phase scattered over a uniform main phase. In Bi-Pb system this second phase is identified to be the ɛ phase comprising of Bi dissolved in Pb and in Bi-Ge system the second phase is identified to be the segregated Ge, rejected by the Bi lattice on account of limited solubility of Ge in Bi. XRD patterns reveal that the lattices of the doped systems are largely those of bismuth and volume fraction of second phase is negligibly small in both the systems. Cohen's method of least squares refinement for cubic system is modified for Bi lattice, indexed on hexagonal axis and a system of normal equations is set up for pure Bi and both the doped systems. These equations are subjected to least squares treatment to obtain lattice parameters, a and c, of pure Bi, Bi-Pb and Bi-Ge systems. It is reported while the unit cell of pure Bi expands, when Pb is added to it, it contracts when Ge is added to it. Laue back-reflection photographs taken along trigonal [111] direction show that 3-fold symmetry of pure bismuth lattice is retained after doping also

Visual Outcome of Descemet Membrane Endothelial Keratoplasty during the Learning Curve in Initial Fifty Cases

This study was performed to evaluate the clinical outcomes of the first fifty patients who underwent Descemet membrane endothelial keratoplasty (DMEK) during the 3-month postoperative period and to describe the challenges encountered during the learning curve. In this retrospective study, we reviewed the charts of patients who underwent DMEK. All information regarding patient demographics, indication for surgery, preoperative and postoperative visual acuity at 3 months, donor age, and complications encountered intraoperatively and postoperatively was recorded. Donor endothelial cell count at the time of surgery and during the 3-month follow-up was noted. Data were analyzed using SPSS version 17. Fifty eyes of 49 patients were included in the study with majority being female patients (male : female = 2 : 3). Mean age of patients was 56.8 ± 11.4 years with the age range of 22–78 years. The common indications for DMEK were pseudophakic bullous keratopathy –57.1%, Fuchs endothelial dystrophy-34.7%, failed grafts-6.1% (Descemet stripping endothelial keratoplasty (DSEK) and failed penetrating keratoplasty), and others. Preoperative best spectacle-corrected visual acuity was 20/63 in 41.8% of the cases, and 93% had visual acuity of 20/200 or better. Donor size was 8 mm, and average donor endothelial cell count (ECC) was 2919 ± 253 cells/mm2. Average ECC at 3 months postoperatively was 1750 ± 664 cells/mm2, which showed a 40% decrease in ECC. The most common encountered complication was graft detachment, which occurred in 16% cases for which rebubbling was done. Regular follow-up and timely identification of graft detachment may prevent the need for retransplantation

Semimetal-semiconductor transition in Bi-In system

407-416Semimetal-semiconductor transition in Bi-doped with 4 at. % In single crystal is reported for the first time. Resistivity and Hall coefficient measurements performed on single crystalline sample of Bi-In (4at.%) system for an extensive range of temperature from 4.2-300 K, reveal semiconducting behaviour explicitly in the range 30-130 K. Electronic parameters, i.e. carrier concentration and Hall mobility are calculated for the entire temperature range of 4.2-300 K. The pair of light mass bands at Lc and Lv moves up relative to the Tv band resulting in the disappearance of the overlap between the Lc band and the Tv band and an energy gap of the order of 37.3 MeV is introduced between the light electron (Lc) and heavy hole (Tv) band. Further, the direct band gap between Lc and Lv bands is narrowed to a value of 10.9 MeV in comparison to pure bismuth. An impurity level is also reported on account of doping corresponding to activation energy of 4.1 MeV. Results from microhardness measurements and XRD studies of pure Bi and Bi-In (4 at. %) alloy reveal that In makes complete solid solution with Bi and gains effective entry into the lattice, altering the periodicity of Bloch Potential and modifying the band structure of Bi. This seems to be the reason that the transition from semimetal to semiconductor takes place in the Bi In alloy.</span

Fermentation Ability of Gut Microbiota of Wild Japanese Macaques in the Highland and Lowland Yakushima: In Vitro Fermentation Assay and Genetic Analyses

Wild Japanese macaques (Macaca fuscata Blyth) living in the highland and lowland areas of Yakushima are known to have different diets, with highland individuals consuming more leaves. We aim to clarify whether and how these differences in diet are also reflected by gut microbial composition and fermentation ability. Therefore, we conduct an in vitro fermentation assay using fresh feces from macaques as inoculum and dry leaf powder of Eurya japonica Thunb. as a substrate. Fermentation activity was higher for feces collected in the highland, as evidenced by higher gas and butyric acid production and lower pH. Genetic analysis indicated separation of highland and lowland in terms of both community structure and function of the gut microbiota. Comparison of feces and suspension after fermentation indicated that the community structure changed during fermentation, and the change was larger for lowland samples. Analysis of the 16S rRNA V3-V4 barcoding region of the gut microbiota showed that community structure was clearly clustered between the two areas. Furthermore, metagenomic analysis indicated separation by gene and pathway abundance patterns. Two pathways (glycogen biosynthesis I and D-galacturonate degradation I) were enriched in lowland samples, possibly related to the fruit-eating lifestyle in the lowland. Overall, we demonstrated that the more leaf-eating highland Japanese macaques harbor gut microbiota with higher leaf fermentation ability compared with the more fruit-eating lowland ones. Broad, non-specific taxonomic and functional gut microbiome differences suggest that this pattern may be driven by a complex interplay between many taxa and pathways rather than single functional traits