Dinesh Mishra

Systemic and mucosal immune response induced by transcutaneous immunization using Hepatitis B surface antigen-loaded modified liposomes

We have evaluated the efficiency of novel modified liposomes (ethosomes) for transcutaneous immunization (TCI) against Hepatitis B. Antigen-loaded ethosomes were prepared and characterized for shape, lamellarity, fluidity, size distribution, and entrapment efficiency. Spectral bio-imaging and flow cytometric studies showed efficient uptake of Hepatitis B surface antigen (HBsAg)-loaded ethosomes by murine dendritic cells (DCs) in vitro, reaching a peak by 180 min. Transcutaneous delivery potential of the antigen-loaded system using human cadaver skin demonstrated a much higher skin permeation of the antigen in comparison to conventional liposomes and soluble antigen preparation. Topically applied HBsAg-loaded ethosomes in experimental mice showed a robust systemic and mucosal humoral immune response compared to intramuscularly administered alum-adsorbed HBsAg suspension, topically applied plain HBsAg solution and hydroethanolic (25%) HBsAg solution. The ability of the antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes was demonstrated by BrdU assay and a predominantly TH1 type of immune response was observed by multiplex cytometric bead array analysis. HBsAg-loaded ethosomes are able to generate a protective immune response and their ability to traverse and target the immunological milieu of the skin may find a potential application in the development of a transcutaneous vaccine against Hepatitis B virus (HBV).

Enhanced Oromucosal Delivery of Progesterone Via Hexosomes

PurposeFormulation and characterization of progesterone loaded hexosomes employing a novel method for oromucosal delivery.MethodHexosomes were prepared employing a method in which ethanolic solution of lipid phase (monolein and oleic acid) was vortexed with aqueous phase (surfactant solution) and characterized for particle size, morphology and internal structure. FT-IR and confocal laser scanning microscopy (CLSM) were performed to investigate the possible mechanism and penetration pathway of hexosomes within the mucosa.ResultsHexosomes exhibited anisotropy, hexagonal shape and nanometric size (251.2u2009±u20091.8xa0nm). Internal structure confirmed by X-ray diffraction peaks with spacing ratio of √1:√3:√4 proved two-dimensional hexagonal arrangements. Entrapment efficiency of system was greater than 95%. In vitro release studies revealed an enhanced transmucosal flux (4.67u2009±u20090.14xa0μg cm−2 h−1) and decreased lag time (1.54xa0h) across albino rabbit mucosa. FT-IR and CLSM of treated mucosa shows lipid extraction phenomena as well as structural irregularities within intercellular lipids respectively. These irregularities can function as ‘virtual channels’ facilitating hexosome’s penetration.ConclusionDeveloped hexosomes formulation exhibited high entrapment efficiency, high permeability and better stability on storage, thus proposing itself a novel carrier for enhanced oromucosal delivery of progesterone.

Carbohydrate-conjugated multiwalled carbon nanotubes: development and characterization

UNLABELLEDnThis work presents a novel cascade of chemical functionalization of multiwalled carbon nanotubes (MWCNTs) through chemical modification by a carbohydrate, D-galactose. Galactose-conjugated or galactosylated MWCNTs were synthesized involving the sequential steps of carboxylation, acylation, amine modification, and finally, galactose conjugation. The modification of MWCNTs with galactose was investigated by elemental analysis, x-ray diffraction analysis, Fourier transform-infrared spectroscopy, Raman spectroscopy, and zeta potential measurements, at every sequential step of functionalization. Size and surface characteristics of chemically modified MWCNTs were monitored by transmission electron microscopy and scanning electron microscopy. That galactosylation improved the dispersibility of MWCNTs in aqueous solvents was confirmed by investigation of their dispersion characteristics at different pH values. Thus, the galactosylated MWCNTs as developed could be used for delivery of different bioactive(s) as well as active ligand (galactose)-based targeting to hepatic tissue.nnnFROM THE CLINICAL EDITORnThis work presents a novel cascade of functionalization of multiwalled carbon nanotubes (MWCNTs) through chemical modification by a carbohydrate. Galactosylation improves the dispersibility of MWCNTs in aqueous solvents. The galactosylated MWCNTs could be used for delivery of different bioactive(s) as well as active ligand-based targeting to hepatic tissue.

Comparative evaluation of hepatitis B surface antigen–loaded elastic liposomes and ethosomes for human dendritic cell uptake and immune response

UNLABELLEDnThe aim of the present study was to evaluate two vesicular carrier systems, ethosomes and elastic liposomes loaded with hepatitis B surface antigen, for in vitro qualitative and quantitative uptake by human dendritic cells (DCs) and ability to stimulate T lymphocytes. Quantitative uptake of antigen-loaded carriers was documented by flow cytometry, and internalization of the systems by the DCs was studied using spectral bioimaging. Ability of antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes and levels of TH1/TH2 cytokines were also examined using flow cytometry. Both vesicular carrier systems as antigen delivery modules and DCs as antigen-presenting cells were able to generate a protective immune response. However, ethosomes were found to have higher internalizing ability and immunogenicity in comparison with elastic liposomes. These properties of ethosomes coupled with their skin-navigating potential, make it an attractive vehicle for development of a transcutaneous vaccine against hepatitis B in preference to elastic liposomes.nnnFROM THE CLINICAL EDITORnTwo carrier systems for more potent vaccine administration - ethosomes and elastic liposomes loaded with hepatitis B surface antigen - are compared. Ethosomes demonstrated higher internalizing ability and immunogenicity. Due to their known skin-navigating potential, ethosomes may represent an attractive vehicle for development of a transcutaneous vaccine against hepatitis B.

Ethinylestradiol-loaded ultraflexible liposomes: pharmacokinetics and pharmacodynamics.

This study aimed to develop ultraflexible liposomes as an alternative to the oral route, which would enhance the bioavailability and reduce the toxicity of ethinylestradiol. Ultraflexible liposomes of ethinylestradiol using an optimized concentration of surfactants were prepared and characterized in vitro. The effect of surfactant type under non‐occlusive conditions on transdermal permeability was assessed. A histopathological study was performed to assess the action of ethinylestradiol on the uterus and ovaries. The pharmacokinetics of free ethinylestradiol (following single oral administration and one day of application to the skin), ultraflexible liposomal ethinylestradiol and non‐flexible liposomal ethinylestradiol were studied in female Sprague—Dawley rats. Insignificant differences in size between the ultraflexible liposomal formulations containing optimized concentrations of different surfactants were observed. Ultraflexible liposomes can penetrate through pores much smaller than their own diameter. The transdermal permeability of lipophilic surfactant was greater than that of hydrophilic surfactant. The release of ethinylestradiol from the proposed formulation through rat skin was found to be constant. The histopathological study showed that the ultraflexible liposomal transdermal drug delivery system for ethinylestradiol provided effective contraception by follicular cell lysis, depletion of zona granulosa and ova, and by increasing the uterine mucosal and endometrial proliferation. Encapsulation of ethinylestradiol in ultraflexible liposomes modified the pharmacodynamics and pharmacokinetics of the contraceptive agent, resulting in a marked improvement in bioavailability and optimized therapy.

Toxicological investigation of surface engineered fifth generation poly (propyleneimine) dendrimers in vivo

Dendrimers are three dimensional polymers, nanoscopic in size, most widely explored in the field of drug delivery in recent times. In order to establish these polymers as controlled and targeted drug delivery systems, they should be non-toxic, biocompatible and biodegradable. The purpose of the present study is to investigate the toxicological profile of fifth generation poly (propyleneimine) dendrimers (PPI) and some of its surface engineered derivatives. Functionalized PPI dendrimers (TPPI, MPPI and TuPPI) were synthesized to mask the primary amino groups responsible for the positive charge and associated toxicity. Each polymer is administered in three different doses: 2.5 mg/kg, 25 mg/kg and 250 mg/kg (i.e., low, intermediate and high dose) to Wister rats, and blood as well as tissue samples were collected after 24 h and 15 days. Decrease in RBC count and hemoglobin content after 24 h, in case of animals administered with PPI suggests hemolytic activity of PPI. Significant increase in SGOT, SGPT and LDH indicates that PPI causes severe damage to the membranes of the various tissues of the body, especially that of the liver leading to the leakage of these marker enzymes in blood. Sections of liver of animals administered with PPI showed signs of tissue degeneration after 24 h. No signs of toxicity were observed in case of animals administered with functionalized PPI. Neither PPI nor its surface engineered derivatives showed any signs of immunogenicity. It can be concluded that functionalization of dendrimers leads to drastic reduction of toxicity and increases biocompatibility.