Magnetic Drug Targeting: Preclinical in Vivo Studies, Mathematical Modeling, and Extrapolation to Humans.

A sound theoretical rationale for the design of a magnetic nanocarrier capable of magnetic capture in vivo after intravenous administration could help elucidate the parameters necessary for in vivo magnetic tumor targeting. In this work, we utilized our long-circulating polymeric magnetic nanocarriers, encapsulating increasing amounts of superparamagnetic iron oxide nanoparticles (SPIONs) in a biocompatible oil carrier, to study the effects of SPION loading and of applied magnetic field strength on magnetic tumor targeting in CT26 tumor-bearing mice. Under controlled conditions, the in vivo magnetic targeting was quantified and found to be directly proportional to SPION loading and magnetic field strength. Highest SPION loading, however, resulted in a reduced blood circulation time and a plateauing of the magnetic targeting. Mathematical modeling was undertaken to compute the in vivo magnetic, viscoelastic, convective, and diffusive forces acting on the nanocapsules (NCs) in accordance with the Nacev-Shapiro construct, and this was then used to extrapolate to the expected behavior in humans. The model predicted that in the latter case, the NCs and magnetic forces applied here would have been sufficient to achieve successful targeting in humans. Lastly, an in vivo murine tumor growth delay study was performed using docetaxel (DTX)-encapsulated NCs. Magnetic targeting was found to offer enhanced therapeutic efficacy and improve mice survival compared to passive targeting at drug doses of ca. 5-8 mg of DTX/kg. This is, to our knowledge, the first study that truly bridges the gap between preclinical experiments and clinical translation in the field of magnetic drug targeting.

Passively Targeted Curcumin-Loaded PEGylated PLGA Nanocapsules for Colon Cancer Therapy In Vivo.

Clinical applications of curcumin for the treatment of cancer and other chronic diseases have been mainly hindered by its short biological half-life and poor water solubility. Nanotechnology-based drug delivery systems have the potential to enhance the efficacy of poorly soluble drugs for systemic delivery. This study proposes the use of poly(lactic-co-glycolic acid) (PLGA)-based polymeric oil-cored nanocapsules (NCs) for curcumin loading and delivery to colon cancer in mice after systemic injection. Formulations of different oil compositions are prepared and characterized for their curcumin loading, physico-chemical properties, and shelf-life stability. The results indicate that castor oil-cored PLGA-based NC achieves high drug loading efficiency (≈18% w(drug)/w(polymer)%) compared to previously reported NCs. Curcumin-loaded NCs internalize more efficiently in CT26 cells than the free drug, and exert therapeutic activity in vitro, leading to apoptosis and blocking the cell cycle. In addition, the formulated NC exhibits an extended blood circulation profile compared to the non-PEGylated NC, and accumulates in the subcutaneous CT26-tumors in mice, after systemic administration. The results are confirmed by optical and single photon emission computed tomography/computed tomography (SPECT/CT) imaging. In vivo growth delay studies are performed, and significantly smaller tumor volumes are achieved compared to empty NC injected animals. This study shows the great potential of the formulated NC for treating colon cancer.

Magnetically Decorated Multi-Walled Carbon Nanotubes as Dual MRI and SPECT Contrast Agents.

Carbon nanotubes (CNTs) have been proposed as one of the most promising nanomaterials to be used in biomedicine for their applications in drug/gene delivery as well as biomedical imaging. The present study developed radio-labeled iron oxide decorated multi-walled CNTs (MWNT) as dual magnetic resonance (MR) and single photon emission computed tomography (SPECT) imaging agents. Hybrids containing different amounts of iron oxide were synthesized by in situ generation. Physicochemical characterisations revealed the presence of superparamagnetic iron oxide nanoparticles (SPION) granted the magnetic properties of the hybrids. Further comprehensive examinations including high resolution transmission electron microscopy (HRTEM), fast Fourier transform simulations (FFT), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) assured the conformation of prepared SPION as γ-Fe2O3. High r2 relaxivities were obtained in both phantom and in vivo MRI compared to the clinically approved SPION Endorem®. The hybrids were successfully radio-labeled with technetium-99m through a functionalized bisphosphonate and enabled SPECT/CT imaging and γ-scintigraphy to quantitatively analyze the biodistribution in mice. No abnormality was found by histological examination and the presence of SPION and MWNT were identified by Perls stain and Neutral Red stain, respectively. TEM images of liver and spleen tissues showed the co-localization of SPION and MWNT within the same intracellular vesicles, indicating the in vivo stability of the hybrids after intravenous injection. The results demonstrated the capability of the present SPION-MWNT hybrids as dual MRI and SPECT contrast agents for in vivo use.

Plasmid DNA ionisable lipid nanoparticles as non-inert carriers and potent immune activators for cancer immunotherapy.

Immunotherapy is currently a standard of care in the treatment of many malignancies. However, predictable side effects caused by systemic administration of highly immunostimulatory molecules have been a serious concern within this field. Intratumoural expression or silencing of immunogenic and immunoinhibitory molecules using nucleic acid-based approaches such as plasmid DNA (pDNA) and small interfering RNA (siRNA), respectively, could represent a next generation of cancer immunotherapy. Here, we employed lipid nanoparticles (LNPs) to deliver either non-specific pDNA and siRNA, or constructs targeting two prominent immunotherapeutic targets OX40L and indoleamine 2,3-dioxygenase-1 (IDO), to tumours in vivo. In the B16F10 mouse model, intratumoural delivery of LNP-formulated non-specific pDNA and siRNA led to strong local immune activation and tumour growth inhibition even at low doses due to the pDNA immunogenic nature. Replacement of these non-specific constructs by pOX40L and siIDO resulted in more prominent immune activation as evidenced by increased immune cell infiltration in tumours and tumour-draining lymph nodes. Consistently, pOX40L alone or in combination with siIDO could prolong overall survival, resulting in complete tumour regression and the formation of immunological memory in tumour rechallenge models. Our results suggest that intratumoural administration of LNP-formulated pDNA and siRNA offers a promising approach for cancer immunotherapy.

Cellular uptake and in vivo distribution of mesenchymal-stem-cell-derived extracellular vesicles are protein corona dependent.

Extracellular vesicles (EVs) derived from mesenchymal stem cells are promising nanotherapeutics in liver diseases due to their regenerative and immunomodulatory properties. Nevertheless, a concern has been raised regarding the rapid clearance of exogenous EVs by phagocytic cells. Here we explore the impact of protein corona on EVs derived from two culturing conditions in which specific proteins acquired from media were simultaneously adsorbed on the EV surface. Additionally, by incubating EVs with serum, simulating protein corona formation upon systemic delivery, further resolved protein corona-EV complex patterns were investigated. Our findings reveal the potential influences of corona composition on EVs under in vitro conditions and their in vivo kinetics. Our data suggest that bound albumin creates an EV signature that can retarget EVs from hepatic macrophages. This results in markedly improved cellular uptake by hepatocytes, liver sinusoidal endothelial cells and hepatic stellate cells. This phenomenon can be applied as a camouflage strategy by precoating EVs with albumin to fabricate the albumin-enriched protein corona-EV complex, enhancing non-phagocytic uptake in the liver. This work addresses a critical challenge facing intravenously administered EVs for liver therapy by tailoring the protein corona-EV complex for liver cell targeting and immune evasion.

Ammonium and guanidinium dendron-carbon nanotubes by amidation and click chemistry and their use for siRNA delivery.

A series of multi-walled carbon nanotube (MWCNT) conjugates is described, functionalized with different dendrons bearing positive charges at their termini (i.e. ammonium or guanidinium groups). The dendrimeric units are anchored to the nanotube scaffolds using two orthogonal synthetic approaches, amidation and click reactions. The final nanohybrids are characterized by complementary analytical techniques, while their ability to interact with siRNA is investigated by means of agarose gel electrophoresis. The demonstration of the cell uptake capacity, the low cytotoxicity, and the ability of these cationic conjugates to silence cytotoxic genes suggests them to be promising carriers for genetic material.

Anti-tumor antibody isotype response can be modified with locally administered immunoadjuvants.

In situ vaccination with immunostimulatory compounds is a demonstrated means to treat tumors preclinically. While these therapeutic effects have been attributed to the actions of T cells or innate immune activation, characterisation of the humoral immune response is seldom performed. This study aims to identify whether the injection of immunoadjuvants, Addavax (Adda) and cytosine-phosphorothioate-guanine oligodeoxynucleotide (CpG), intratumorally can influence the antibody response. Specifically, whether intratumoral injection of immunoadjuvants can alter the tumor-specific antibody target, titre and isotype. Following this, the study aimed to investigate whether serum obtained from in situ vaccinated mice could neutralise circulating tumor cells. Serum was obtained from mice bearing B16F10-OVA-Luc-GFP tumors treated with immunoadjuvants. Antibody targets' titre and isotype were assessed by indirect ELISA. The ability of serum to neutralise circulating cancer cells was evaluated in a B16F10 pseudo-metastatic model. It was observed that tumor-bearing mice mount a specific anti-tumor antibody response. Antibody titre and target were unaffected by in situ vaccination with immunoadjuvants; however, a higher amount of IgG2c was produced in mice receiving Adda plus CpG. Serum from in situ vaccinated mice was unable to neutralise circulating B16F10 cells. Thus, this study has demonstrated that anti-tumor antibody isotype may be modified using in situ vaccination; however, this alone is not sufficient to neutralise circulating cancer cells.

Evaluation of a DoE based approach for comprehensive modelling of the effect of lipid nanoparticle composition on nucleic acid delivery.

Therapeutic nucleic acids (TNAs) comprise an alternative to conventional drugs for cancer therapy. Recently, stable nucleic acid lipid particles (SNALPs) have been explored to deliver TNA efficiently and safely both in vitro and in vivo. Small interfering RNA (siRNA) and messenger RNA (mRNA) based drugs have been suggested for a wide range of pathologies, and their respective lipid nanoparticle (LNP) formulations have been optimised using a Design of Experiments (DoE) approach. However, it is uncertain as to whether data obtained from DoE using simple experimental outputs can be used to generate a general heuristic for delivery of diverse TNA both in vitro and in vivo. Using plasmid DNA (pDNA), for which limited DoE optimisation has been performed, and siRNA to represent the two extremities of the TNA spectrum in terms of size and biological requirements, we performed a comparative DoE for both molecules and assessed the predictive qualities of the model both in vitro and in vivo. By producing a minimum run of 24 SNALP formulations with different lipid compositions incorporating either pDNA or siRNA, DoE models were successfully established for predicting the effect of individual lipid composition on particle size, TNA encapsulation and transfection both in vitro and in vivo. The results showed that the particle size, and in vitro and in vivo transfection efficiency of both pDNA and siRNA SNALP formulations were affected by lipid compositions. The encapsulation efficiency of pDNA SNALPs but not siRNA SNALPs was affected by the lipid composition. Notably, the optimal lipid compositions of SNALPs for pDNA/siRNA delivery were not identical. Furthermore, in vitro transfection efficiency could not be used to predict promising LNP candidates in vivo. The DoE approach described in this study may provide a method for comprehensive optimisation of LNPs for various applications. The model and optimal formulation described in this study can serve as a foundation from which to develop other novel NA containing LNPs for multiple applications such as NA based vaccines, cancer immunotherapies and other TNA therapies.

Intranasal administration of edaravone nanoparticles improves its stability and brain bioavailability.

The clinical application of EDV, a potent antioxidant drug approved for amyotrophic lateral sclerosis (ALS), is limited by its short biological half-life and poor water solubility necessitating hospitalization during intravenous infusion. Nanotechnology-based drug delivery constitutes a powerful tool through inferring drug stability and targeted drug delivery improving drug bioavailability at the diseased site. Nose-to-brain drug delivery offers direct access to the brain bypassing the blood brain barrier and reducing systemic biodistribution. In this study, we designed EDV-loaded poly(lactic-co-glycolic acid) (PLGA)-based polymeric nanoparticles (NP-EDV) for intranasal administration. NPs were formulated by the nanoprecipitation method. Morphology, EDV loading, physicochemical properties, shelf-life stability, in vitro release and pharmacokinetic assessment in mice were conducted. EDV was efficiently loaded into ∼90 nm NPs, stable up to 30 days of storage, at ∼3% drug loading. NP-EDV reduced H2O2-induced oxidative stress toxicity in mouse microglial cell line BV-2. Optical imaging and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) showed that intranasal delivery of NP-EDV offered higher and more sustained brain uptake of EDV compared to intravenous administration. This study is the first of its kind to develop an ALS drug in a nanoparticulate formulation for nose-to-brain delivery raising hope to ALS patients where currently treatment options are limited to two clinically approved drugs only.

Spatiotemporal tracking of gold nanorods after intranasal administration for brain targeting.

Intranasal administration is becoming increasingly more attractive as a fast delivery route to the brain for therapeutics circumventing the blood-brain barrier (BBB). Gold nanorods (AuNRs) demonstrate unique optical and biological properties compared to other gold nanostructures due to their high aspect ratio. In this study, we investigated for the first time the brain region-specific distribution of AuNRs and their potential as a drug delivery platform for central nervous system (CNS) therapy following intranasal administration to mice using a battery of analytical and imaging techniques. AuNRs were functionalized with a fluorescent dye (Cyanine5, Cy5) or a metal chelator (diethylenetriaminepentaacetic dianhydride, DTPA anhydride) to complex with Indium-111 via a PEG spacer for optical and nuclear imaging, respectively. Direct quantification of gold was achieved by inductively coupled plasma mass spectrometry. Rapid AuNRs uptake in mice brains was observed within 10 min following intranasal administration which gradually reduced over time. This was confirmed by the 3 imaging/analytical techniques. Autoradiography of sagittal brain sections suggested entry to the brain via the olfactory bulb followed by diffusion to other brain regions within 1 h of administration. The presence of AuNR in glioblastoma (GBM) tumors following intranasal administration was also proven which opens doors for AuNRs applications, as nose-to-brain drug delivery carriers, for treatment of a range of CNS diseases.

PSMA-targeted NIR probes for image-guided detection of prostate cancer.

Tumour-targeted near-infrared (NIR) optical imaging is an emerging tool for the detection of malignant tissues. This modality can be useful in both diagnosis and intraoperative visualisation, to help defining tumour margins and allow a more precise removal of all the cancerous mass during surgery. In this context, we have developed a series of NIR fluorescent probes that target the prostate-specific membrane antigen (PSMA), an established biomarker overexpressed in prostate cancer. Four new NIR imaging agents were prepared by conjugating the well-known urea-based PSMA targeting module to the NIR fluorophore Cy7.5, with linkers of 7, 10, 17 and 24 atoms. The affinity of each probe for PSMA was assessed through competitive binding and IC50 measurement in prostate cancer cells, using a previously reported PSMA-targeted NIR probe (i.e. PSMA-IRDye800CW) as reference. The NIR probe PSMA-Cy7.5_2 demonstrated a high affinity for PSMA (i.e. IC50 = 58.8 nM) and was further studied in mouse xenograft models of prostate cancer, to assess its ability to image PSMA positive tumour tissues. While PSMA-Cy7.5_2 out-performed PSMA-IRDye800CW in vitro, its tumour accumulation in vivo was not as evident. Further micellar aggregation studies indicated that the relatively higher hydrophobic property of PSMA-Cy7.5_2 may lower its bioavailability and tissue distribution following systemic injection, limiting its ability of targeting PSMA tumour in vivo. Nevertheless, the excellent binding capability of PSMA-Cy7.5_2 renders this probe a valid lead for further structural optimisation to develop imaging analogues with high affinity and specificity for PSMA, as required for effective NIR fluorescence-guided applications pre-clinically and clinically.

Combinatory Delivery of Etoposide and siCD47 in a Lipid Polymer Hybrid Delays Lung Tumor Growth in an Experimental Melanoma Lung Metastatic Model.

This study investigated the feasibility of lipid polymer hybrid nanoparticles (LPH) as a platform for the combinatorial delivery of small interfering RNA (siRNA) and etoposide (Eto). Different Eto loaded LPH formulations (LPH Eto ) are prepared. The optimized cationic LPH Eto  with a particle size of 109.66 ± 5.17 nm and Eto entrapment efficiency (EE %) of 80.33 ± 2.55 is used to incorporate siRNA targeting CD47 (siCD47), a do not eat me marker on the surface of cancer cells. The siRNA-encapsulating LPH (LPH siNEG-Eto ) has a particle size of 115.9 ± 4.11 nm and siRNA EE % of 63.54 ± 4.36 %. LPHs improved the cellular uptake of siRNA in a dose- and concentration-dependent manner. Enhanced cytotoxicity (3.8-fold higher than Eto solution) and high siRNA transfection efficiency (≈50 %) are obtained. An in vivo biodistribution study  showed a preferential uptake of the nanosystem into lung, liver, and spleen. In an experimental pseudo-metastatic B16F10 lung tumor model, a superior therapeutic outcome can be observed in mice treated with combinatory therapy. Immunological studies revealed elevated CD4+, CD8+ cells, and macrophages in the lung following combinatory treatment. The study suggests the potential of the current system for combinatory chemotherapy and immunotherapy for the treatment of lung cancer or lung metastasis.

Comparison between Fluorescence Imaging and Elemental Analysis to Determine Biodistribution of Inorganic Nanoparticles with Strong Light Absorption.

Black porous silicon nanoparticles (BPSi NPs) are known as highly efficient infrared light absorbers that are well-suitable for photothermal therapy (PTT) and photoacoustic imaging (PAI). PTT and PAI require a sufficient number of effectively light-absorbing NPs to be accumulated in tumor after intravenous administration. Herein, biodistribution of PEGylated BPSi NPs with different sizes (i.e., 140, 200, and 300 nm in diameter) is investigated after intravenous administration in mice. BPSi NPs were conjugated with fluorescent dyes Cy5.5 and Cy7.5 to track them in vitro and in vivo, respectively. Optical imaging with an in vivo imaging system (IVIS) was found to be an inadequate technique to assess the biodistribution of the dye-labeled BPSi NPs in vivo because the intrinsic strong absorbance of the BPSi NPs interfered fluorescence detection. This challenge was resolved via the use of inductively coupled plasma optical emission spectrometry to analyze ex vivo the silicon content in different tissues and tumors. The results indicated that most of the polyethylene glycol-coated BPSi NPs were found to accumulate in the liver and spleen after intravenous injection. The smallest 140 nm particles accumulated the most in tumors at an amount of 9.5 ± 3.4% of the injected dose (concentration of 0.18 ± 0.08 mg/mL), the amount known to produce sufficient heat for cancer PTT. Furthermore, the findings from the present study also suggest that techniques other than optical imaging should be considered to study the organ biodistribution of NPs with strong light absorbance properties.

An "eat me" combinatory nano-formulation for systemic immunotherapy of solid tumors.

Rational: Tumor immunogenic cell death (ICD), induced by certain chemotherapeutic drugs such as doxorubicin (Dox), is a form of apoptosis potentiating a protective immune response. One of the hallmarks of ICD is the translocation of calreticulin to the cell surface acting as an 'eat me' signal. This manuscript describes the development of a stable nucleic acid-lipid particles (SNALPs) formulation for the simultaneous delivery of ICD inducing drug (Dox) with small interfering RNA (siRNA) knocking down CD47 (siCD47), the dominant 'don't eat me' marker, for synergistic enhancement of ICD. Methods: SNALPs loaded with Dox or siCD47 either mono or combinatory platforms were prepared by ethanol injection method. The proposed systems were characterized for particle size, surface charge, entrapment efficiency and in vitro drug release. The ability of the SNALPs to preserve the siRNA integrity in presence of serum and RNAse were assessed over 48 h. The in vitro cellular uptake and gene silencing of the prepared SNALPs was assessed in CT26 cells. The immunological responses of the SNALPs were defined in vitro in terms of surface calreticulin expression and macrophage-mediated phagocytosis induction. In vivo therapeutic studies were performed in CT26 bearing mice where the therapeutic outcomes were expressed as tumor volume, expression of CD4 and CD8 as well as in vivo silencing. Results: The optimized SNALPs had a particle size 122 ±6 nm and an entrapment efficiency > 65% for both siRNA and Dox with improved serum stability. SNALPs were able to improve siRNA and Dox uptake in CT26 cells with enhanced cytotoxicity. siCD47 SNALPs were able to knockdown CD47 by approximately 70% with no interference from the presence of Dox. The siCD47 and Dox combination SNALPs were able to induce surface calreticulin expression leading to a synergistic effect on macrophage-mediated phagocytosis of treated cells. In a tumor challenge model, 50% of mice receiving siCD47 and Dox containing SNALPs were able to clear the tumor, while the remaining animals showed significantly lower tumor burden as compared to either monotreatment. Conclusion: Therefore, the combination of siCD47 and Dox in a particulate system showed potent anti-tumor activity which merits further investigation in future clinical studies.

Enhanced Delivery of Neuroactive Drugs via Nasal Delivery with a Self-Healing Supramolecular Gel.

This paper reports the use of a self-assembling hydrogel as a delivery vehicle for the Parkinson's disease drug l-DOPA. Based on a two-component combination of an l-glutamine amide derivative and benzaldehyde, this gel has very soft rheological properties and self-healing characteristics. It is demonstrated that the gel can be formulated to encapsulate l-DOPA. These drug-loaded gels are characterized, and rapid release of the drug is obtained from the gel network. This drug-loaded hydrogel has appropriate rheological characteristics to be amenable for injection. This system is therefore tested as a vehicle for nasal delivery of neurologically-active drugs-a drug delivery strategy that can potentially avoid first pass liver metabolism and bypass the blood-brain barrier, hence enhancing brain uptake. In vitro tests indicate that the gel has biocompatibility with respect to nasal epithelial cells. Furthermore, animal studies demonstrate that the nasal delivery of a gel loaded with 3 H-labeled l-DOPA out-performed a simple intranasal l-DOPA solution. This is attributed to longer residence times of the gel in the nasal cavity resulting in increased blood and brain concentrations. It is demonstrated that the likely routes of brain penetration of intranasally-delivered l-DOPA gel involve the trigeminal and olfactory nerves connecting to other brain regions.

Green synthesis of methoxy-poly(ethylene glycol)-block-poly(l-lactide-co-glycolide) copolymer using zinc proline as a biocompatible initiator for irinotecan delivery to colon cancer in vivo.

Poly(lactic-co-glycolic acid) (PLGA) is the most commonly described biocompatible copolymer used in biomedical applications. In this work, a green synthetic approach based on the biocompatible zinc proline complex, as an initiator for PLGA synthesis, is reported for the first time for the synthesis of methoxy-poly(ethylene glycol)-block-poly(l-lactic-co-glycolic acid) (mPEG-PLGA). mPEG-PLGA with controlled molecular weight and narrow polydispersity was synthesised. Its potential for delivery of irinotecan (Ir), a poorly water-soluble chemotherapeutic drug used for the treatment of colon and pancreatic cancer, was studied. Nanoparticles of controlled size (140-160 nm), surface charge (∼-10 mV), release properties and cytotoxicity against CT-26 (colon) and BxPC-3 (pancreatic) cancer cells, were prepared. Tumor accumulation was confirmed by optical imaging of fluorescently labelled nanoparticles. Unlike Tween® 80 coated NP-Ir, the Pluronic® F-127 coated NP-Ir exhibits significant tumor growth delay compared to untreated and blank formulation treated groups in the CT-26 subcutaneous tumor model, after 4 treatments of 30 mg irinotecan per kg dose. Overall, this proof-of-concept study demonstrates that the newly synthesized copolymer, via a green route, is proven to be nontoxic, requires fewer purification steps and has potential applications in drug delivery.

Evaluation of cell surface reactive immuno-adjuvant in combination with immunogenic cell death inducing drug for in situ chemo-immunotherapy.

Apoptotic cells and cell fragments, especially those produced as a result of immunogenic cell death (ICD), are known to be a potential source of cancer vaccine immunogen. However, due to variation between tumours and between individuals, methods to generate such preparations may require extensive ex vivo personalisation. To address this, we have utilised the concept of in situ vaccination whereby an ICD inducing drug is injected locally to generate immunogenic apoptotic fragments/cells. These fragments are then adjuvanted by a co-administered cell reactive CpG adjuvant. We first evaluate means of labelling tumour cells with CpG adjuvant, we then go on to demonstrate in vitro that labelling is preserved following apoptosis and, furthermore, that the apoptotic body-adjuvant complexes are readily transferred to macrophages. In in vivo studies we observe synergistic tumour growth delays and elevated levels of CD4+ and CD8+ cells in tumours receiving adjuvant drug combination. CD4+/CD8+ cells are likewise elevated in the tumour draining lymph node and activated to a greater extent than individual treatments. This study represents the first steps toward the evaluation of rationally formulated drug-adjuvant combinations for in situ chemo-immunotherapy.

A novel natural GRAS-grade enteric coating for pharmaceutical and nutraceutical products.

In this study, enteric coatings based exclusively on naturally occurring ingredients were reported. Alginate (Alg) and pectin (Pec) blends with or without naturally occurring glyceride, glycerol monostearate (GMS), were initially used to produce solvent-casted films. Incorporating GMS in the natural polymeric films significantly enhanced the acid-resistance properties in gastric medium. Theophylline tablets coated with Alg-Pec blends without GMS disintegrated shortly after incubation in gastric medium (pH 1.2), leading to a premature and complete release of theophylline. Interestingly, tablets coated with Alg-Pec blends that contain the natural glyceride (GMS) resisted the gastric environment for 2 h with minimal drug release (<5%) and disintegrated rapidly following introduction to the intestinal medium, allowing a fast and complete drug release. Furthermore, the coating system proved to be stable for six months under accelerated conditions. These findings are particularly appealing to nutraceutical industry as they provide the foundation to produce naturally-occurring GRAS based enteric coatings.

Surface engineered nanoliposomal platform for selective lymphatic uptake of asenapine maleate: In vitro and in vivo studies.

Asenapine maleate (ASPM) is an antipsychotic drug prescribed for the treatment of schizophrenia and bipolar disorder. ASPM possesses low oral bioavailability due to extensive hepatic metabolism. Therefore, RGD peptide conjugated liposomes loaded with ASPM were prepared to target Peyer's patches in the intestine which in-turn get access into intestinal lymphatic system thereby increasing the oral bioavailability of the drug. Liposomes were evaluated for size, zeta potential, differential scanning calorimetry (DSC), FTIR spectroscopy, X-ray diffraction (XRD), shape and morphology, in vitro drug release, cell line studies, everted intestinal uptake, pharmacodynamics, pharmacokinetics, tissue distribution, targetability and stability studies. In vitro drug release study showed the sustained release of drug from the formulations. Optimized liposomes (size <110 nm) showed greater permeability across the Caco2 + Raji B co-culture model in vitro and everted rat ileum ex vivo. Liposomes showed increase in bioavailability and high efficacy in reducing the L-DOPA-carbidopa induced locomotor count compared to plain drug. Liposomes also showed high concentration of drug in the brain after their oral administration. Imaging studies showed that RGD peptide conjugated liposomes were successful in targeting the Peyer's patches, both in vivo and ex vivo. The study successfully demonstrated the improved pharmacokinetics and efficacy profile of ASPM by using a ligand conjugated targeted liposomal system.

Engineering red-emitting multi-functional nanocapsules for magnetic tumour targeting and imaging.

In this work we describe the formulation and characterisation of red-emitting polymeric nanocapsules (NCs) incorporating superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic tumour targeting. The self-fluorescent oligomers were synthesised and chemically conjugated to PLGA which was confirmed by NMR spectroscopy, FT-IR spectroscopy and mass spectrometry. Hydrophobic SPIONs were synthesised through thermal decomposition and their magnetic and heating properties were assessed by SQUID magnetometry and calorimetric measurements, respectively. Magnetic nanocapsules (m-NCs) were prepared by a single emulsification/solvent evaporation method. Their in vitro cytotoxicity was examined in CT26 colon cancer cells. The formulated fluorescent m-NCs showed good stability and biocompatibility both in vitro and in vivo in CT 26 colon cancer models. Following intravenous injection, accumulation of m-NCs in tumours was observed by optical imaging. A higher iron content in the tumours exposed to a magnetic field, compared to the contralateral tumours without magnetic exposure in the same animal, further confirmed the magnetic tumour targeting in vivo. The overall results show that the engineered red-emitting m-NCs have great potential as multifunctional nanocarriers for multi-model bioimaging and magnetic-targeted drug delivery.