Kavit Raval

Nanoemulsion: Concepts, development and applications in drug delivery

ABSTRACT Nanoemulsions are biphasic dispersion of two immiscible liquids: either water in oil (W/O) or oil in water (O/W) droplets stabilized by an amphiphilic surfactant. These come across as ultrafine dispersions whose differential drug loading; viscoelastic as well as visual properties can cater to a wide range of functionalities including drug delivery. However there is still relatively narrow insight regarding development, manufacturing, fabrication and manipulation of nanoemulsions which primarily stems from the fact that conventional aspects of emulsion formation and stabilization only partially apply to nanoemulsions. This general deficiency sets up the premise for current review. We attempt to explore varying intricacies, excipients, manufacturing techniques and their underlying principles, production conditions, structural dynamics, prevalent destabilization mechanisms, and drug delivery applications of nanoemulsions to spike interest of those contemplating a foray in this field.

Bridging small interfering RNA with giant therapeutic outcomes using nanometric liposomes

The scope of RNAi based therapeutics is unquestionable. However, if we dissect the current trend of clinical trials for afore mentioned drug class, some stark trends appear: 1) naked siRNA only exerts influence in topical mode whilst systemic delivery requires a carrier and 2) even after two decades of extensive efforts, not even a single siRNA containing product is commercially available. It was therefore felt that a perspective simplifying the unique intricacies of working with a merger of siRNA and liposomes from a pharmaceutical viewpoint could draw the attention of a wider array of interested researchers. We begin from the beginning and attempt to conduit the gap between theoretical logic and experimental/actual constraints. This, in turn could stimulate the next generation of investigators, gearing them to tackle the conundrum, which is siRNA delivery.

Targeting tumor associated macrophages (TAMs) via nanocarriers

&NA; Recruitment of inflammatory cells to tumor has been well documented, with the most frequent inhabitants being macrophages termed as tumor associated macrophages, (TAMs). Their presence was thought to be an evidence of immune system initiating a fight response towards the tumor, i.e. immune surveillance. This is the case too initially, when TAMs majorly exhibit an M1 phenotype, but their continued presence in tumor microenvironment brings about their polarization to M2 phenotype, which not only participate in continued sustenance of existing tumor but also open up deleterious avenues for further progression and metastasis of cancer. Current perspective is built around this very premise and focuses specifically on TAMs and how they are being targeted by researchers working in annals of nanomedicine. To do so, we dwell into tumor microenvironment and focus on nanotechnology based drug delivery aspects which have either been already or can be potentially employed in the future to target tumor associated macrophages for improved immunoadjuvant therapy of cancer. Graphical abstract Figure. No caption available.

Nanosized complexation assemblies housed inside reverse micelles churn out monocytic delivery cores for bendamustine hydrochloride

Objective We explore a plausible method of targeting bendamustine hydrochloride (BM) to circulatory monocytes by exploiting their intrinsic endocytic/phagocytic capability. Methods We do so by complexation of sodium alginate and chitosan inside dioctyl sulfo succinate sodium (AOT) reverse micelles to form bendamustine hydrochloride loaded nanoparticles (CANPs). Dynamic light scattering, electrophoretic mobility and UV spectroscopy were used to detail intra‐micellar complexation dynamics and to prove that drug was co‐captured during interaction of carbohydrate polymers. A fluorescent conjugate of drug (RBM) was used to trace its intracellular fate after its loading into nanoparticles. Results CANPs were sized below 150 nm, had 75% drug entrapment and negative zeta potential (−30 mV). Confocal microscopy demonstrated that developed chitosan alginate nanoparticles had the unique capability to carry BM specifically to its site of action. Quantitative and mechanism based cell uptake studies revealed that monocytes had voracious capacity to internalize CANPs via simultaneous scavenger receptor based endocytic and phagocytic mechanism. Comparative in vitro pharmacokinetic studies revealed obtainment of significantly greater intracellular drug levels when cells were treated with CANPs. This caused reduction in IC50 (22.5 ± 2.1 &mgr;g/mL), enhancement in G2M cell cycle arrest, greater intracellular reactive oxygen species generation, and increased apopotic potential of bendamustine hydrochloride in THP‐1 cells. Conclusion Selective monocytic targeting of bendamustine hydrochloride using carbohydrate constructs can prove advantageous in case of leukemic disorders displaying overabundance of such cells. Graphical abstract No caption available.

Macrophage-targeted chitosan anchored PLGA nanoparticles bearing doxorubicin and amphotericin B against visceral leishmaniasis

Novel chitosan-coated nanoparticles with a high payload of amphotericin B (AmB) and doxorubicin (Dox) were formulated employing a nanoprecipitation technique and evaluated for antileishmanial activity against Leishmania donovani. FTIR, DSC and TG-DTA analysis ensured the physicochemical compatibility of drugs and polymers. The chitosan-coated optimized nanoparticle formulation resulted in a mean particle size; 374.4 ± 4.8 nm, PDI; 0.227 ± 0.035 and zeta potential; (+) 32.9 ± 1.10 mV. The entrapment efficiency was determined to be 70.2 ± 4.76 and 93.86 ± 2.61% for AmB and Dox respectively. An in vitro drug release study demonstrated the release of 27.29 and 36.93% AmB and Dox, respectively after 24 h from chitosan-coated PLGA nanoparticles which is slower than the release obtained from uncoated PLGA nanoparticles of AmB and Dox (32.82 and 57.93% AmB and Dox respectively after 24 h). Stability studies confirmed no remarkable alterations in the physicochemical properties of nanoparticles. Cs-PLGA-ABDx was less hemotoxic (22.87 ± 0.487%) than PLGA-ABDx (36.71 ± 2.08%) and the ABDx suspension (97.04 ± 5.01%) at 42.78 μg mL−1 AmB and 80 μg mL−1 Dox. Cell uptake investigation showed the mean florescence intensity of chitosan-coated PLGA-FITC was 2.02 fold higher than uncoated PLGA-FITC nanoparticles. The cytotoxicity in J774A.1 cells revealed Cs-PLGA-ABDx was less cytotoxic compared to the ABDx suspension and PLGA-ABDx, whereas the IC50 of Cs-PLGA-ABDx against infected macrophages was significantly (p < 0.05) lower than PLGA-ABDx indicating the effectiveness of Cs-PLGA-ABDx. No significant increase in the biomedical markers AST, BUN and PC was observed in Cs-PLGA-ABDx treated groups at 1 and 3 mg kg−1 dose. These experimental findings put forward Cs-PLGA-ABDx to be a suitable alternative in the management of visceral leishmaniasis.

Click biotinylation of PLGA template for biotin receptor oriented delivery of doxorubicin hydrochloride in 4T1 cell induced breast cancer

PLGA was functionalized with PEG and biotin using click chemistry to generate a biotin receptor targeted copolymer (biotinylated-PEG-PLGA) which in turn was used to fabricate ultrafine nanoparticles (BPNP) of doxorubicin hydrochloride (DOX) for effective delivery in 4T1 cell induced breast cancer. However, adequate entrapment of a hydrophilic bioactive like DOX in a hydrophobic polymer system made of PLGA is not usually possible. We therefore modified a conventional W/O/W emulsion method by utilizing NH4Cl in the external phase to constrain DOX in dissolved polymer phase by suppressing DOXs inherent aqueous solubility as per common ion effect. This resulted in over 8-fold enhancement in entrapment efficiency of DOX inside BPNP, which otherwise is highly susceptible to leakage due to its relatively high aqueous solubility. TEM and DLS established BPNP to be sized below 100 nm, storage stability studies showed that BPNP were stable for one month at 4 °C, and in vitro release suggested significant control in drug release. Extensive in vitro and in vivo studies were conducted to propound anticancer and antiproliferative activity of BPNP. Plasma and tissue distribution study supplemented by pertinent in vivo fluorescence imaging mapped the exact fate of DOX contained inside BPNP once it was administered intravenously. A comparative safety profile via acute toxicity studies in mice was also generated to out rightly establish usefulness of BPNP. Results suggest that BPNP substantially enhance anticancer activity of DOX while simultaneously mitigating its toxic potential due to altered spatial and temporal presentation of drug and consequently deserve further allometric iteration.

Chitosan coated PluronicF127 micelles for effective delivery of Amphotericin B in experimental visceral leishmaniasis

The goal of study was to develop micellar formulation of Amphotericin B (AmB) to improve its antileishmanial efficacy. AmB loaded pluronic F127 (PF 127) micelles were developed and coated with chitosan (Cs-PF-AmB-M) to accord immunoadjuvant and macrophage targeting properties. Hemolysis and cytotoxicity studies demonstrated that Cs-PF-AmB-M was 7.93 fold (at 20μg/ml AmB concentration) and 9.35 fold less hemolytic and cytotoxic, respectively in comparison to AmB suspension. Flow cytometry studies indicated that Cs-PF-FITC-M was 21.97 fold higher internalized byJ774A.1 macrophage in comparison to PF-FITC-M.Cs-PF-AmB-M showed excellent in-vitro (1.82 fold in compared to AmB suspension) and in-vivo (75.84±7.91% parasitic inhibition) antileishmanial activity against macrophage resident intracellular promastigotes and Leishmania donovani infected Syrian hamsters, respectively. Chitosan coating stimulated a Th1 immune response mediating auxiliary immunotherapeutic action as judged by in-vitro and in-vivo cytokine and mRNA expression. Toxicity studies demonstrated normal blood urea nitrogen (BUN) and plasma creatinine (PC) level and no sign of abnormal histopathology upon intravenous administration of micellar formulations. Pharmacokinetic profiling and tissue distribution studies indicated that AmB was preferentially localized in macrophage harboring tissue instead of kidney, thereby circumventing the characteristic nephrotoxicity. Conclusively, Cs-PF-AmB-M could be a viable alternative for the current immuno and chemotherapy of visceral leishmaniasis (VL).

Doxorubicin Hydrochloride Loaded Zymosan-Polyethylenimine Biopolymeric Nanoparticles for Dual ‘Chemoimmunotherapeutic’ Intervention in Breast Cancer

ObjectiveTo utilize nanoparticles produced by condensation of zymosan (an immunotherapeutic polysaccharide) with pegylated polyethylenimine (PEG-PEI) for dual intervention in breast cancer by modulating tumor microenvironment and direct chemotherapy.MethodPositively charged PEG-PEI and negatively charged sulphated zymosan were utilized for electrostatic complexation of chemoimmunotherapeutic nanoparticles (ChiNPs). ChiNPs were loaded with doxorubicin hydrochloride (DOX) for improved delivery at tumor site and were tested for in-vivo tolerability. Biodistribution studies were conducted to showcase their effective accumulation in tumor hypoxic regions where tumor associated macrophages (TAMs) are preferentially recruited.ResultsChiNPs modulated TAMs differentiation resulting in decrement of CD206 positive population. This immunotherapeutic action was furnished by enhanced expression of Th1 specific cytokines. ChiNPs also facilitated an anti-angiogenetic effect which further reduces the possibility of tumor progression and metastasis.

Improved chemotherapy against breast cancer through immunotherapeutic activity of fucoidan decorated electrostatically assembled nanoparticles bearing doxorubicin

Immunotherapeutic nanoparticles (NPs) could be a viable option for delivering cytotoxic agents in a manner which suppresses their toxic manifestations. Doxorubicin (DOX) loaded NPs were prepared using fucoidan (FCD), an immunomodulatory polysaccharide and evaluated against cancer. FCD was electrostatically assembled with cationic polyethylenimine (PEI) through intermolecular electrostatic interactions to develop an immunomodulatory platform to deliver DOX. FCD NPs offered improved cytotoxicity (2.64 folds), cell cycle arrest in G1-S phase (34.65%) and apoptosis (66.12%) in tumor cells compared to free DOX. The enhanced apoptosis was due to raised mitochondrial depolarization (88.00%). In vivo anticancer activity in 4T1 induced tumor bearing BALB/c mice demonstrated a 2.95 folds enhanced efficacy of NPs. Importantly, NPs treatment generated an immunotherapeutic response indicated by gradual increment of the plasma IL-12 levels and reversed polarization of tumor associated macrophages (TAMs) towards M1 subtype. Furthermore, pharmacokinetic study suggested that NPs administration in tumor infested mice caused serum DOX levels to vary in a biphasic pattern, with twin peaks occurring at 1 h and 6 h which help in maintaining preferential drug localization in tumor. Developed NPs would be an excellent approach for improved immune-chemotherapy (in terms of efficacy, safety and immunocompetency) against cancer.