Pullulan based oral thin film formulation of zolmitriptan: Development and optimization using factorial design.

The goal of study was to formulate and characterize pullulan based oral thin film (OTF) of zolmitriptan by solvent casting method. Based on preliminary trials, glass, PEG 400 and sucralose were selected as casting surface, water-miscible plasticizer and sweetener for OTF, respectively. A 32 factorial design was used to study the effect of amount of PEG 400 (X1) and sucralose (X2) as independent variables on tensile strength (Y1), elasticity (Y2), % in-vitro drug release in phosphate buffer of pH 6.8 at 5min (Q5min, Y3) and overall taste of OTF (Y4) as responses. OTF of batch F4 (PEG 400, 200mg; sucralose, 12mg) was identified as an optimized batch showing in-vitro, in-vivo disintegration time 20.70 and 21.58s, respectively; 95.53% Q5min; satisfactory thickness, strength, % elongation, ease of handling, smooth mouthfeel, excellent overall taste; even distribution of all ingredients in pullulan OTF (SEM study); and stable film at specified conditions concluding that pullulan, PEG 400 and sucralose are used in combination to make palatable, stable OTF of zolmitriptan.

Histomorphological Spectrum of Duodenal Pathology in Functional Dyspepsia Patients.

INTRODUCTION: Functional Dyspepsia (FD) is one of the most common causes of gastrointestinal symptoms aetiology of which is poorly understood. AIM: To study duodenal histomorphological features and their relationship with Helicobacter pylori (H Pylori) infection in patients of FD. MATERIALS AND METHODS: This case control study included 50 cases of FD patients selected according to Rome III criteria and 30 age and sex matched controls. These were subjected to oesophago-gastro-duodenoscopy, rapid urease test for detection of H. pylori on gastric antral biopsy and duodenal biopsy from second part of duodenum for histopathological evaluation by light microscopy. Ten antral urease positive cases of FD with highest Intraepithelial Lymphocyte Count (IEL) were subjected to Immunohistochemistry (IHC). RESULTS: Duodenal inflammation was an invariable feature noted in FD. Morphological spectrum consisted of increased IEL in 72%, increased duodenal eosinophils in 92%, presence of focal villous atrophy in 16%, lymphoid aggregates, colonic metaplasia, and duodenal H. pylori infection in 4% each. Gastric H. pylori positivity was noted in 48% cases of FD. Increased duodenal IEL count and duodenal eosinophilia was noted in 75%, 87.5% such cases. Same was noted respectively, with 61.5% and 95.15% cases with gastric H. pylori negativity. In cases of FD, duodenal IEL and eosinophil count in lamina propria showed statistically significant rise when compared with control and had positive correlation with gastric H pylori infection. On IHC, increased expression of CD 8 was noted in duodenal IEL and lymphocytes in lamina propria as compared to CD4. CONCLUSION: Our study provided some insight in pathogenesis of FD and role of H. pylori in its aetiology.

Development and optimization of modified release IPN macromolecules of oxcarbazepine using natural polymers.

The study shows development and optimization of modified release interpenetrating polymer network (IPN) macromolecules (beads) of oxcarbazepine using sodium alginate-egg albumin prepared by ionotropic gelation method and CaCl2 as a cross-linker. Independent variables were identified based on preliminary study of investigation. The effect of amount of both polymers on drug entrapment efficiency (DEE,%), bead size (µm) and cumulative drug release at 8 h (Q8h, %) were optimized using 3(2) factorial design. The DEE, average size and Q8h were found in the range of 65.08-91.02%, 976-1084 µm and 73.50-94.06% respectively. The beads were also characterized by FTIR, DSC, SEM and XRD. The experiential responses were coincided well with predicted values obtained by Design-Expert(®) 8.0.6.1 software. The swelling of beads were influenced by the pH of a release medium. The in vitro drug release from IPN beads exhibited sustained release Hixson-Crowell pattern with anomalous non-Fickian diffusion mechanism concluding that the developed sodium alginate-egg albumin IPN composite beads are suitable for sustained delivery of oxcarbazepine for desired period.

Azurin-like protein blocks invasion of Toxoplasma gondii through potential interactions with parasite surface antigen SAG1.

Some pathogenic bacteria produce factors that have evolved a capacity to neutralize competing microbes. The cupredoxin family protein azurin, produced by Pseudomonas aeruginosa, exhibits a remarkable ability to impede invasion of a number of diverse intracellular pathogens, including the human AIDS virus human immunodeficiency virus type 1 and the protozoan parasite Plasmodium falciparum (which causes malaria). Here we report that azurin and an azurin-like protein (Laz) from gonococci/meningococci have activity against Toxoplasma, an apicomplexan parasite that causes opportunistic infection in immunocompromised individuals. We demonstrate that the mechanism of action for Laz involves interfering with the ability of Toxoplasma to adhere to host cells. Computer structural analysis reveals that azurin shares structural features with the predominant surface antigen SAG1, which is known to play an important role in parasite attachment. Interestingly, azurin also has structural similarities to a monoclonal antibody to SAG1. Surface plasmon resonance binding studies validate that SAG1 interacts strongly with Laz and, to lesser extent, azurin. Moreover, Toxoplasma mutants lacking SAG1 are not as susceptible to the growth-inhibitory effects of Laz. Collectively, our data show that Toxoplasma adhesion can be significantly impaired by Laz, and to some extent by azurin, via interactions with SAG1. These observations indicate that Laz can serve as an important tool in the study of host-pathogen interactions and is worthy of further study for development into potential therapeutic agents.

Cupredoxin-cancer interrelationship: azurin binding with EphB2, interference in EphB2 tyrosine phosphorylation, and inhibition of cancer growth.

Azurin is a member of a family of metalloproteins called cupredoxins. Although previously thought to be involved in electron transfer, azurin has recently been shown to preferentially enter cancer cells than normal cells and induce apoptosis in such cells. Azurin also demonstrates structural similarity to a ligand known as ephrinB2, which binds its cognate receptor tyrosine kinase EphB2 to initiate cell signaling. Eph/ephrin signaling is known to be involved in cancer progression. We now demonstrate that azurin binds to the EphB2-Fc receptor with high affinity. We have localized a C-terminal domain of azurin (Azu 96-113) that exhibits structural similarity to ephrinB2 at the G-H loop region known to be involved in receptor binding. A synthetic peptide (Azu 96-113) as well as a GST fusion derivative GST-Azu 88-113 interferes with the growth of various human cancer cells. In a prostate cancer cell line DU145 lacking functional EphB2, azurin or its GST-fusion derivatives had little cytotoxic effect. However, in DU145 cells expressing functional EphB2, azurin and GST-Azu 88-113 demonstrated significant cytotoxicity, whereas ephrinB2 promoted cell growth. Azurin inhibited the ephrinB2-mediated autophosphorlyation of the EphB2 tyrosine residue, thus interfering in upstream cell signaling and contributing to cancer cell growth inhibition.

Azurin, Plasmodium falciparum malaria and HIV/AIDS: inhibition of parasitic and viral growth by Azurin.

Azurin, a member of a family of copper-containing proteins involved in electron transfer called cupredoxins, demonstrates structural features similar to the variable domains of the immunoglobulin superfamily members. An azurin-like protein called Laz with an additional N-terminal 39 amino acid peptide known as H.8 epitope is present on the surface of gonnococci and meningococci. We demonstrate that azurin, Laz and H.8-azurin can bind to the C-terminal cleavage product MSP1-19 of merozoite surface protein 1 (MSP1) of the malarial parasite Plasmodium falciparum and significantly reduce parasitemia. Azurin and Laz also bound strongly to HIV-1 gp120. Interestingly, azurin could not only bind to gp120 but also to the dendritic cell-specific adhesion receptor DC-SIGN, mimicking the functionality of the intercellular adhesion molecule ICAM-3 with which it also binds avidly. Furthermore, these three proteins significantly suppressed HIV-1 growth in peripheral blood mononuclear cells and such suppression appeared to be occurring at an entry stage in the infection process. The presence of both antimalarial and antiretroviral activity in azurin, H.8-azurin and Laz makes these proteins, or peptides derived from them, potential therapeutic agents in the treatment of malaria, HIV-1 infections or coinfections with both P. falciparum and HIV-1.

Reversible photocontrol of peptide helix content: adjusting thermal stability of the cis state.

Cross-linking reagents based on an azobenzene core can be used to reversibly photoregulate secondary structure when introduced as intramolecular bridges in peptides and proteins. Photoisomerization of the azobenzene core in the trans to cis direction is triggered by photon absorption but isomerization from cis to trans occurs thermally as well as photochemically. The rate of the thermal process effectively determines the half-life of the cis form as well as the extent to which the trans form can be recovered. We designed and characterized a series of methanethiosulfonate (MTS)-bearing thiol-reactive azo-benzene-based cross-linkers. These cross-linkers are shown to permit photoregulation of helix content in a test peptide with half-lives for the cis conformation ranging from 11 s to 43 h at 25 degrees C. The cross-linkers described here thus broaden the range of reagents available for reversible photocontrol of peptide and protein conformation.

Photoinduced electron-transfer along alpha-helical and coiled-coil metallopeptides.

A peptide-based electron-transfer system has been designed in which the specific positions of redox-active metal complexes appended to either an alpha-helix, or an alpha-helical coiled-coil, can be reversed to test the effect of the helix dipole in controlling photoinduced electron-transfer rates. Two 30-residue apopeptides were prepared having the following sequences: (I) Ac-K-(IEALEGK)(ICALEGK)(IEALEHK)(IEALEGK)-G-amide, and (II) Ac-K-(IEALEGK)(IHALEGK)-(IEALECK)(IEALEGK)-G-amide. Each apopeptide was reacted first with [Ru(bpy)2(phen-ClAc)]2+, where bpy = 2,2'-bipyridine and phen-ClAc = 5-chloroacetamido-1,10-phenanthroline, to attach the ruthenium polypyridyl center to the cysteine side-chain of the polypeptide. The isolated products were then reacted with [Ru(NH3)5(H2O)]2+ to yield the binuclear electron-transfer metallopeptides ET-I and ET-II. In these systems, electron-transfer occurred from the photoexcited ruthenium polypyridyl donor to the pentammine ruthenium (III) acceptor such that the electron-transfer occurred toward the negative end of the helix dipole in ET-I, and toward the positive end in ET-II. Circular dichroism spectroscopy showed that both peptides exist as dimeric alpha-helical coiled-coils in 100 mM phosphate buffer at pH 7, and as monomeric alpha-helices in the lower dielectric solvents 2,2,2-trifluoroethanol, and a 1:1 (v/v) mixture of CH2Cl2 and 2,2,2-trifluoroethanol. The peptides were predominately (i.e., 65-72%) alpha-helical in these solvents. The emission lifetime behavior of ET-I was seen to be identical to that of ET-II in each of the three solvents: no evidence for directional electron-transfer rates was observed. Possible reasons for this behavior are discussed.