Shailja Tiwari

Lectin anchored PLGA nanoparticles for oral mucosal immunization against hepatitis B

Present study aimed at exploring the potential of α-l-fucose specific, LTA (Lotus tetragonolobus from Winged or Asparagus pea) as a homing device for nanocarriers to target the M cell for elicitation of strong immune response. LTA grafted poly(lactic-co-glycolic acids) (PLGA) nanoparticles encapsulating hepatitis B surface antigen (HBsAg) was developed and characterized for shape, size, polydispersity index, zeta potential, and antigen loading efficiency. The peyer’s patch uptake was studied by using confocal laser scanning microscopy technique using dual staining technique. The immune stimulating potential was assessed by measuring anti-HBsAg titer in serum of balb/c mice. Induction of the mucosal immunity was assessed by estimating secretory immunoglobulin A level in the salivary, intestinal, and vaginal secretion and cytokine (interleukin-2 and interferon-γ) levels in the spleen homogenates. Furthermore, IgG1 and IgG2a isotype were determined to confirm the TH1/TH2 mixed immune response. The LTA anchored PLGA nanoparticles have demonstrated approximately four-fold increase in the degree of interaction with the bovine submaxillary mucin (BSM). The results demonstrated that LTA anchored PLGA nanoparticles elicited strong mucosal and systemic response and hence could be a promising carrier adjuvant for the M cell targeted oral mucosal immunization against Hepatitis B.

Evaluation of mucoadhesive PLGA microparticles for nasal immunization.

In this study, hepatitis B surface antigen (HBsAg) loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were prepared and coated with chitosan and trimethyl chitosan (TMC) to evaluate the effect of coating material for nasal vaccine delivery. The developed formulations were characterized for size, zeta potential, entrapment efficiency, and mucin adsorption ability. Plain PLGA microparticles demonstrated negative zeta potential. However, coated microparticles showed higher positive zeta potential. Results indicated that TMC microparticles demonstrated substantially higher mucin adsorption when compared to chitosan-coated microparticles and plain PLGA microparticles. The coated and uncoated microparticles showed deposition in nasal-associated lymphoid tissue under fluorescence microscopy. The coated and uncoated microparticles were then administered intranasally to mice. Immune-adjuvant effect was determined on the basis of specific antibody titer observed in serum and secretions using enzyme-linked immunosorbent assay. It was observed that coated particles showed a markedly increased anti-HBsAg titer as compared to plain PLGA microparticles, but the results were more pronounced with the TMC-coated PLGA microparticles.

Recent advances in mucosal delivery of vaccines: role of mucoadhesive/biodegradable polymeric carriers

Importance of the field: The mucosal delivery of vaccines provides the basis for induction of humoral, cellular and mucosal immune responses against infectious diseases. The delivery of antigens to and through mucosal barriers always remains challenging due to adverse physiological conditions (pH and enzymes) and biological barriers created by tight epithelial junctions restricting transportation of macromolecules. Mucoadhesive and biodegradable polymers offer numerous advantages in therapeutic delivery of proteins/antigens particularly through the mucosal route by protecting antigens from degradation, increasing concentration of antigen in the vicinity of mucosal tissue for better absorption, extending their residence time in the body and/or targeting them to sites of antigen uptake. Furthermore, antigen can be delivered more effectively to the antigen presenting cells by anchoring the ligand having affinity on the surface of carrier for the receptors present on the mucosal epithelial cells. Areas covered in this review: The present review covers various polymeric carriers, which allow the possibility of modification and manipulation of their properties, thereby, enhancing the effectiveness of mucosal vaccines. This article reviews the recent literature and patents in the field of vaccine delivery using mucoadhesive polymeric carriers. What the reader will gain: The reader will gain insights into various natural polymers, synthetic polymers and ligand derived polymeric carrier systems studied to enhance mucosal immunization. Take home message: Biodegradable polymeric carriers represent a promising approach for mucosal delivery of vaccine.

Development and characterization of novel carrier gel core liposomes based transmission blocking malaria vaccine

The aim of present work was to investigate the potential utility of novel carrier gel core liposomes for intramuscular delivery of transmission blocking malaria antigen Pfs25 and to evaluate the effect of co-administration of vaccine adjuvant CpGODN on immune enhancement of recombinant protein antigen Pfs25. In the present work we have prepared gel core liposomes containing core of biocompatible polymer poly acrylic acid in phospholipid bilayer by reverse phase evaporation method and characterized for various in vitro parameters. In process stability of the encapsulated antigen was evaluated by SDS-PAGE followed by western blotting. The immune stimulating ability was studied by measuring anti-Pfs25 antibody titer in serum of Balb/c mice following intramuscular administration of various formulations. A Significant and perdurable immune responses was obtained after intramuscular administration of gel core liposomes encapsulated Pfs25 as compared to Pfs25 loaded conventional liposomes. Moreover co-administration of CpGODN in liposomes (conventional and gel core) was found to further increase the immunogenicity of vaccine. The result indicates high potential of gel core liposomes for their use as a carrier adjuvant for intramuscular delivery of recombinant antigen Pfs25 based transmission blocking malaria vaccine.

Aquasomes—A Nanoparticulate Approach for the Delivery of Antigen

The development of compound that enhances immune responses to recombinant or synthetic epitopes is of considerable importance in vaccine research. Of the many different types of immunopotentiating compounds that have been researched, aquasomes are of considerable promise, because of their potency and adjuvanticity. Aquasomes were prepared by self-assembling of hydroxyapatite by co-precipitation method and thereafter preliminary coated with polyhydroxyl oligomers (cellobiose and trehalose) and subsequently adsorbed with bovine serum albumin (BSA) as a model antigen. The prepared systems were characterized for size, shape, antigen-loading efficiency, in vitro antigen stability, and in vivo performance. BSA-immobilized aquasomes were around 200 nm in diameter and spherical in shape and had approximately 20–30% BSA-loading efficiency. The immunological activity of the formulated aquasomes was compared with plain BSA and better results were observed. Studies also indicated that aquasome formulations could elicit combined T-helper 1 (Th1) and Th2 immune response.

Biodegradable Polymer Based Particulate Carrier(s) for the Delivery of Proteins and Peptides

Construction of safe and effective delivery systems for proteins and peptides is demand of current clinical practices. Biodegradable polymers based particulates carriers fulfill much of the requirement in this applicable field. Number of marketed products related to biodegradable polymers encapsulating proteins is increasing. However, it has not achieved its proper place since problems related to the protein processing and stabilization limits the scientific community. In this present review we have summarized various aspects related to the formulation and processing of biodegradable polymerized microparticles/ nanoparticles for delivery of therapeutic proteins and peptides. A brief introduction of biodegradable polymers has been incorporated for readers benefit. In addition, biodegradable polymers based carriers designed for vaccine delivery has been incorporated in detail. Functionalized biodegradable carrier(s) for site specific delivery of proteineous matter has also been discussed.

Cationic ligand appended nanoconstructs: A prospective strategy for brain targeting

The objective of present research was to evaluate the potential of engineered solid lipid nanoparticles (SLNs) as vectors to bypass the blood brain barrier. Anti-cancer agent, doxorubicin (DOX) loaded SLNs were prepared and conjugated with cationic bovine serum albumin (CBSA). The formation of CBSA tethered and plain SLNs were characterized by FTIR, NMR, and TEM analyses. Physicochemical parameters such as particle size/polydispersity index and zeta-potential were also determined. Cellular uptake studies on HNGC-1 cell lines depicted almost six times enhanced uptake of ligand conjugated SLNs as compared to plain DOX solution. Furthermore, CBSA conjugated formulation was more cytotoxic as compared to free drug or unconjugated SLNs. Transendothelial studies showed maximum transcytosis ability of CBSA conjugated SLNs across brain capillary endothelial cells. In vivo pharmacokinetic parameters and biodistribution pattern demonstrated efficiency of the system for spatial and temporal delivery of DOX to brain tissues. Lastly, hematological, nephrotoxic as well as hepatotoxic data suggested CBSA conjugated formulations to be less immunogenic compared to plain formulations.

Development of Self-assembled Nanoceramic Carrier Construct(s) for Vaccine Delivery

Hydroxyapatite (HA) has been extensively investigated as scaffolds for tissue engineering, as drug delivery agents, as non-viral gene carriers, as prosthetic coatings, and composites. Recent studies in our laboratory demonstrated the immunoadjuvant properties of HA when administered with malarial merozoite surface protein-119 (MSP-119). HA nanoceramic carrier was prepared by co-precipitation method that comprises of sintering and spray-drying technique. Prepared systems were characterized for crystallinity, size, shape, and antigen loading efficiency. Small size and large surface area of prepared HA demonstrated good adsorption efficiency of immunogens. Prepared nanoceramic formulations also showed slower in vitro antigen release and slower biodegrability behavior, which may lead to a prolonged exposure to antigen-presenting cells and lymphocytes. Furthermore, addition of mannose in nanoceramic formulation may additionally lead to increased stability and immunological reactions. Immunization with MSP-119 in nanoceramic-based adjuvant systems induced a vigorous immunoglobulin G (IgG) response, with higher IgG2a than IgG1 titers. In addition considerable amount of IFN-g and IL-2 was observed in spleen cells of mice immunized with nanoceramic-based vaccines. On the contrary, mice immunized with MSP-119 alone or with alum did not exhibit a significant cytotoxic response. The antibody responses to vaccine co-administered with HA was a mixed Th1/Th2 compared to the Th2-biased response obtained with alum. The prepared HA nanoparticles exhibit physicochemical properties that appear promising to make them a suitable immunoadjuvant to be used as antigen carriers for immunopotentiation.

Gel core liposomes: An advanced carrier for improved vaccine delivery

Abstract Many sub-unit vaccines are successful in preventing the occurrence of disease, but their use is largely restrained due to low immunogenicity. Novel carrier-based vaccine could serve as a vaccine adjuvant to overcome low immunogenicity of sub-unit vaccines. The use of liposomes as a delivery system for antigen is well recognized but they are unstable and release of antigen from them cannot be controlled over a prolonged period of time. To overcome the limitation of liposomes, this study has developed gel core liposomes in which a core of polymer was incorporated inside the liposomal vesicles, which serve the function of skeleton and provide mechanical strength to vesicles. In the present investigation BSA-loaded gel core liposomes were prepared by reverse phase evaporation method and characterized for vesicles size, shape, entrapment efficiency, in vitro release and stability studies. The in vivo studies to evaluate antigen presenting potential of the gel-core liposomes was performed in Balb/c mice by measuring the immune response elicited by intramuscular administration of BSA-loaded gel core liposomes and compared with intramuscularly administered BSA-loaded conventional liposomes, alum adsorbed BSA and plain antigen. Results indicate that intramuscular immunization with gel core liposomes induces efficient systemic antibody responses against BSA as compared to other formulations. The gel core liposomal formulation provides good entrapment efficiency, enhanced in vitro stability, prolonged antigen release and effective immunoadjuvant property, justifying its potential for improved vaccine delivery.

Influence of various lipid core on characteristics of SLNs designed for topical delivery of fluconazole against cutaneous candidiasis

Dermal delivery of fluconazole (FLZ) is still a major limitation due to problems relating to control drug release and achieving therapeutic efficacy. Recently, solid lipid nanoparticles (SLNs) were explored for their potential of topical delivery, possible skin compartments targeting and controlled release in the skin strata. The retention and accumulation of drug in skin is affected by composition of SLNs. Hence, the aim of this study was to develop FLZ nanoparticles consisted of various lipid cores in order to optimize the drug retention in skin. SLNs were prepared by solvent diffusion method and characterized for various in vitro and in vivo parameters. The results indicate that the SLNs composed of compritol 888 ATO (CA) have highest drug encapsulation efficiency (75.7 ± 4.94%) with lower particle size (178.9 ± 3.8 nm). The in vitro release and skin permeation data suggest that drug release followed sustained fashion over 24 h. The antifungal activity shows that SLNs made up of CA lipid could noticeably improve the dermal localization. In conclusion, CA lipid based SLNs are represents a promising carrier means for the topical treatment of skin fungal infection as an alternative to the systemic delivery of FLZ.