Glioblastoma: Current Status, Emerging Targets, and Recent Advances.

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

Development and characterization of spray-dried porous nanoaggregates for pulmonary delivery of anti-tubercular drugs.

Tuberculosis, MTB or tubercle bacillus (TB) is a lethal, infectious disease mainly caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. In this study, guar gum-based porous nanoaggregates were formulated by precipitation technique with two frontline antitubercular drugs, i.e. isoniazid and rifampicin. The formulations were optimized on the basis of various evaluation parameters such as morphology, density, entrapment efficiency and in vitro drug release. The optimized formulations were administered by inhalable route to Wistar rats for the evaluation of drugs in different organs (lungs, liver and kidneys). High drug encapsulation efficiency was achieved in guar gum porous nanoaggregates, ranging from 50% to 60%. A single pulmonary dose resulted in therapeutic drug concentrations of 30%-50% in the lungs and in other organs (less than 5%) for 24 h. From this study, we can conclude that delivering drugs through pulmonary route is advantageous for local action in lungs. Furthermore, the formulation showed sustained drug release pattern, which could be beneficial for reducing the drug dose or frequency of dosing, thus helpful in improving patient compliance.

Development and characterization of niosomal gel for topical delivery of benzoyl peroxide.

Benzoyl peroxide (BPO) is generally considered as first line treatment against acne. Low water solubility and formation of larger clusters and limited skin permeation upon topical application necessitates the application of high amount of drug for desired action which leads to induction of skin irritation. In the present study, we developed BPO-loaded niosomal formulation to improve its permeation through skin. The niosomes were further loaded in the carbopol gel to improve contact time. The results of the skin permeation study, skin retention study revealed that niosomes can effectively improve the drug permeation through skin. Application of niosomal gel significantly reduced the bacterial load after a treatment of four days. This reduction in bacterial load was further resulted in a significant reduction in the inflammation with minimal skin irritation compared with plain drug and the plain niosomal formulation.

Development and characterization of guar gum nanoparticles for oral immunization against tuberculosis.

The main aim of this study was to develop an effective carrier system containing Ag85A-loaded guar gum nanoparticles for oral vaccination against tuberculosis. Nanoparticles were prepared by Nanoprecipitation method. The developed particles with mean diameter 895.5 ± 14.73 nm and high antigen entrapment seem to be optimum for oral vaccine delivery. The acid protection assay, Peyer's patch uptake study and in-vitro antigen study confirmed that the developed formulations can protect the antigen from harsh gastric environment and can safely deliver the antigen to the intestinal region. In vivo studies data indicated that the developed nanocarriers can induce a strong mucosal as well as systemic immune response. Therefore, the experimental evidence suggests that guar-gum nanoparticle findings indicated that the guar gum nanoparticles can be utilized for safe and effective vaccine delivery via oral route.

Development of probiotic-based immunoparticles for pulmonary immunization against Hepatitis B.

OBJECTIVES: The present study was oriented towards the development of pulmonary vaccine for Hepatitis B using probiotic biomass as an adjuvant. METHODS: The antigen was spray dried in presence of heat treated, formalin treated and live probiotic biomass. KEY FINDINGS: The results indicated that the biomass itself without any additional cryoprotectant is capable of protecting the structural integrity of the antigen. We were able to retain more than 80% of the antigenicity. The scanning electron microscopic images indicated that the formulation bearing live probiotic biomass have spherical size, while the formulations with heat and formalin treated biomass shows irregular shaped particles. The developed formulations were further evaluated for in-vivo immune response. Immunoglobulin G (IgG) titre results were found to be comparable with marketed (aluminium adsorbed) formulations while significantly higher secretory immunoglobulin A titre showed better mucosal immune response than marketed formulation. CONCLUSION: Therefore, the probiotic biomass can be utilized as a potential cryoprotectant as well as a potent immunomodulator.

Development of pH responsive novel emulsion adjuvant for oral immunization and in vivo evaluation.

The present work has been envisaged to develop a pH responsive multiple emulsion (W/O/W) adjuvant for successful antigen delivery via oral route. The formulation was prepared by double emulsion technique using squalene as oil phase and a combination of antigens and Quil A as internal aqueous phase. Squalene emulsion (O/W) adjuvants are well accepted for parenteral administration. Instead of using conventional surfactants, Quil A was incorporated in the internal aqueous compartment for the first time. The microscopic analysis confirmed the formation of the W/O/W multiple emulsions with globule diameter ranging from 7 to 12 µm. Considerably, addition of Quil A resulted in marked improvement in both in vitro stability and immune response. Furthermore, addition of pectin to the external aqueous phase resulted in improved in vitro stability. A formulation with gel like structure was formed when pectin was used as stabilizer and also accounted with a significant increase in viscosity (from 275.3 cP to 330.4 cP) in the simulated gastric fluid, which reverts back to 290.2 cP after exposure to simulated intestinal fluid. Induction of strong mucosal and systemic immune response suggested that the developed formulation could be useful for the delivery of multiple biomolecules via oral route.

Are the anatomical sites for vaccine administration selected judiciously?

Route of vaccine administration plays an important role in the development of immune response. Antigen administered via different anatomical sites interacts with diverse subsets of antigen presenting cells. Diverse population of antigen presenting cells directs a drastically different immune response. Initially, the recommended routes for vaccine administration were also selected on the basis of clinical trials conducted for the drug molecules. However, physicochemical and pharmaceutical behaviors of proteins (antigens) and chemical compounds are entirely different. Most of the commercial vaccines are injected in the arm or in the scapular region (deltoid muscle). Vaccine administered to these conventional anatomical sites has failed to induce desired immune response due to lack of optimum level of antigen presenting cells. In this review, we have discussed the importance of the selection of anatomical sites for vaccine administration. Mere selection of an optimum site for vaccine administration may drastically change the immune response of the current marketed formulations without any alteration in their existing production plans.

Development and characterization of nano-fiber patch for the treatment of glaucoma.

In the present work polymeric nano-fiber patches was developed for the effective treatment of glaucoma using timolol maleate and dorzolamide hydrochloride as model drugs. The nano-fibers were prepared by electrospinning technique and were characterized on the basis of fiber diameter, morphology, entrapment efficiency, mucoadhesive strength, and drug release behavior, etc. Final formulations were inserted in the cul-de-sac of glaucoma induced rabbits and the efficacy of the formulation was evaluated. The results clearly indicated the potential of the developed formulation for occur drug delivery. There was a significant fall in the intraocular pressure compared to commercial eye drops.

Microfold-cell targeted surface engineered polymeric nanoparticles for oral immunization.

Present work was envisaged to develop novel M-cell targeted polymeric particles that are capable of protecting the antigen from harsh gastric conditions. Ulex europaeus agglutinin (UEA-1) lectin was anchored for selective delivery of antigen to gut-associated lymphoid tissue (GALT). In the present investigation, chitosan nanoparticles were prepared by ionic gelation followed by antigen (bovine serum albumin, BSA) adsorption. Developed nanoparticles were further coated by UEA-1 lectin conjugated alginate and characterized for size, shape, zeta-potential, entrapment efficiency, and in vitro release. The immunological response of the developed system were performed in Balb/c mice and compared with aluminium hydroxide gel-based conventional vaccine. Results indicated that immunization with UEA-1 lectin conjugated alginate-coated particles induces efficient systemic as well as mucosal immune responses against BSA compared to other formulations. Aluminium-based vaccine dominated throughout the study, while failed in case of mucosal antibody. Additionally, IgG1 and IgG2a isotypes were determined to confirm the TH1/TH2 mixed immune response. The developed formulation exhibited superior systemic response along with dominating mucosal immunity. These data demonstrate the potential of UEA-alginate-coated nanoparticles as effective delivery system via oral route.

Development of transmucosal patch using nanofibers.

In the present work we have attempted to develop a novel transmucosal patch of diclofenac sodium using electrospun polycaprolactone (PCL) nanofibers. PCL nanofibers were prepared by electrospinning techniques using different polymer concentrations. Nanofibers formulations were characterized by SEM, FTIR, drug loading, and in-vitro release study using Franz diffusion cell. Studies revealed the nanofibers fabricated from 13% PCL were fracture-free, non-beaded, and ultrafine with 120 nm diameter. Release studies demonstrated the sustained release behavior of PCL nanofibers. Nanofibers can be exploited for transmucosal drug delivery of NSAID with improved therapeutic efficacy.

Nanocrystallization of poorly water soluble drugs for parenteral administration.

Approximately 50% active substances discovered by combinatorial chemistry and high-throughput screening show poor solubility in water. Out of various available approaches "Nanoedege technology" (Combination of Precipitation and Homogenization) was selected. Amphotericin B (Amp B) was used as a model drug. Three different preparations of Amp B were produced by using three different surfactants Tween80, Pluronic F68, Soya Lecithin and assessed for their efficacy and stability. In this study the Amp B nanosuspension formulation, with the smaller particle size, can be effectively produced with the Nanoedge Method. The pharmacokinetic profiles of Amp B when given in the nanosuspension formulation were different compared to the corresponding raw drug.

Surface engineered nanoparticles for oral immunization.

A rationally designed oral vaccine should be successfully delivered to the intestinal mucosal immune cells, and induce both humoral and cellular counterparts of immunity along with the mucosal immune response. The aim of this study is to mimic these natural infections and excel the utility of a specific ligand for beta1 integrin (RGD peptide) to target M cells which seems to be the only portal for any particulate matter in GIT. The in vivo studies have shown higher antibody titre for alginate coated chitosan nanoparticles compared to plain chitosan nanoparticles. RGD peptide conjugated alginate coated chitosan nanoparticles proved to be the suitable carrier system for antigen delivery to gut associated lymphoid tissue. Based upon the release kinetics and strong systemic as well as mucosal immune response we can conclude that this cost effective carrier construct can be utilized for oral vaccination.

Development and characterization of oleic acid vesicles for the topical delivery of fluconazole.

Fatty acids have been widely used as adjuvant, vehicles in drug delivery viz penetration enhancers in topical delivery and in polymeric micelles to provide sustained release. However, the present investigation aims at exploring the potential of fatty acid vesicles for the topical delivery of fluconazole. Vesicles were prepared by film hydration method using oleic acid as a fatty acid principal component. Developed vesicles were characterized for size, size distribution, shape, in vitro release, pH dependent and storage stability, skin irritation study, and ex-vivo skin permeation. Penetration behavior of vesicles was further evaluated and elucidated using confocal microscopic study. Optical microscopy and TEM studies confirmed vesicular dispersion of fatty acid. The vesicles possessed higher entrapment efficiency (44.11%) with optimum vesicle size and homogeneity in regard to size distribution (PDI = 0.234 +/- 0.016) at 7:3 oleic acid-to-fluconazole ratio. In vitro drug release study suggested sustained release of drug from the vesicles. The release pattern followed Higuchian kinetics. The vesicles were fairly stable at refrigerated conditions. Ex-vivo skin permeation and confocal microscopic studies suggested that oleic acid vesicles penetrate the stratum corneum and retain the drug accumulated in the epidermal part of the skin. On the basis of sustained release behavior and skin retention it can be inferred that oleic acid vesicles can serve as a potential carrier for the topical localized delivery of bioactives.