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Posts Tagged ‘Drug delivery’


Engineered Bacteria used as Trojan Horse for Cancer Immunotherapy

Reporter: Irina Robu, PhD

Researchers are using synthetic biology— design and construction of new biological entities such as enzymes, genetic circuits, and cells or the redesign of existing biological systems—is changing medicine leading to innovative solution in molecular-based therapeutics. To address the issue of designing therapies that can induce a potent, anti-tumor immune response researchers at Columbia Engineering and Columbia Irving Medical Center engineered a strain of non-pathogenic bacteria that can colonize tumors in mice. The non-pathogenic bacteria act as Trojan Horse that can lead to complete tumor regression in a mouse model of lymphoma. Their results are currently published in Nature Medicine.

The scientists led by Nicholas Arpaia, used their expertise in synthetic biology and immunology to engineer a strain of bacteria able to grow and multiply in the necrotic core of tumors. The non-pathogenic E. coli are programmed to self-destruct when the bacteria numbers reach a critical threshold, allowing for actual release of therapeutics and averting them from causing havoc somewhere else in the body. Afterward, a small portion of bacteria survive lysis and repopulate the population which allows repeated rounds of drug delivery inside treated tumors.

In the present study, the scientists release a nanobody that targets CD47 protein, which defends cancer cells from being eaten by distinctive immune cells. The mutual effects of bacteria, induced local inflammation within the tumor and the blockage of the CD47 leads to better ingestion and activation of T-cells within the treated tumors. The team deduced that the treatment with their engineered bacteria not only cleared the treated tumors but also reduced the incidence of tumor metastasis.

Before moving to clinical trials, the team is performing proof-of-concept tests, safety and toxicology studies of their immunotherapeutic bacteria in a rand of advanced solid tumor settings in mouse models. They have currently collaborated with Gary Schwartz, deputy director of the Herbert Irving Comprehensive Cancer and have underway a company to translate their promising technology to patients.

SOURCE

Sreyan Chowdhury, Samuel Castro, Courtney Coker, Taylor E. Hinchliffe, Nicholas Arpaia, Tal Danino. Programmable bacteria induce durable tumor regression and systemic antitumor immunity. Nature Medicine, 2019

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Nanoparticles Could Boost Effectiveness of Allergy Shots

Reporter : Irina Robu, PhD

Immunotherapy is a preventive treatment for allergic reactions to substances such as grass pollens, house dust mites and bee venom. The only existing therapy that treats their causes is allergen-specific immunotherapy or allergy shots which can cause severe side effects. For many people, allergies are a seasonal annoyance. But for others, exposure to a particular allergen can cause antagonistic reactions such as itching, breathing problems or even death. Allergy shots can diminish sensitivity by gradually ramping up exposure to the offending substance. Each allergy shot contains a tiny amount of the specific substance or substances that trigger your allergic reactions.

Holger Frey and colleagues report in Biomacromolecules the development of a potentially better allergy shot that uses nanocarriers to address these unwanted issues. In order to develop a safer, cause-based therapy scientist have developed nanoparticles that enclose an allergen and deliver it to specific cells. However, these nanocarriers degrade slowly, hindering the efficiency of the treatment.

Nanocarriers offer the following potential advantages: site-specific delivery of drugs, peptides, and genes, improved in-vitro and in-vivo stability and reduced side effect profile. However, nanoparticles are usually first picked up by the phagocytic cells of the immune system which may promote inflammatory disorders. In order to overcome the limitations, the researchers designed a novel type of nanocarrier created on the biocompatible molecule poly (ethylene glycol) that releases its cargo only in targeted immune cells.

This approach could be used not only for allergies but also can be used for other immunotherapies such as cancer and AIDS.

Source

https://www.eurekalert.org/pub_releases/2015-09/acs-ncb092215.php

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Reducing the Burden of Tuberculosis Treatment

Reporter: Irina Robu, PhD

Tuberculosis is one of the world’s deadliest infectious diseases, which requires six-month course of daily antibiotics. To help overcome that, a team of researchers led by MIT has devised a new way to deliver antibiotics, which they hope will make it easier to cure more patients and reduce health care costs. In their approach a coiled wire loaded with antibiotics is inserted into the patient’s stomach through a nasogastric tube. Once in the stomach, the device slowly releases antibiotics over one month, eliminating the need for patients to take pills every day.

The device is a thin, elastic wire made of nitinol that can change its shape based on temperature. The researchers can string up to 600 “pills” of various antibiotics along the wire, and the drugs are packaged in polymers whose composition can be adjusted to control the rate of drug release once the device go in the stomach. The wire is distributed to the patient’s stomach via a tube inserted through the nose, which is used regularly in hospitals for delivering medications and nutrients. When the wire reaches the higher temperatures of the stomach, it forms a coil, which stops it from passing further through the digestive system. The researchers then tested the device in pigs and found that this device could release different antibiotics at a constant rate for 28 days. Once all of the drugs are delivered, the device is recovered through the nasogastric tube using a magnet that can attract the coil.

Giovanni Traverso and Robert Langer have been working on a variety of pills and capsules that can remain in the stomach and slowly release medication after being swallowed. This type of drug delivery, can expand treatment to several chronic diseases that require daily doses of medication. One capsule that shows promise appears to be for delivering small amounts of drugs to treat HIV and malaria. After being swallowed, the capsule’s outer coating disintegrates, allowing six arms to expand, helping the device to lodge in the stomach. This device can carry about 300 milligrams of drugs which is enough for a week’s worth of HIV treatment but it falls short of the payload of 3 grams of antibiotics every day needed to treat tuberculosis.

The researchers in addition to David Collins, an economist analyzed the potential economic impact of this type of treatment. He determined that if  the treatment is applied in India, costs could be reduced by about $8,000 per patient. I think that such an approach can be helpful for longer regimens required for the treatment of extensively drug-resistant TB and even hepatitis C and this approach can be an vital milestone toward addressing this problem.

 SOURCE

http://news.mit.edu/2019/stomach-device-antibiotics-tuberculosis-0313?utm_source=&utm_medium=&utm_campaign=&hootPostID=a4ebcfad3e9982776b3c1883db19141c

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Walking DNA Nanorobot

Reporter: Irina Robu, PhD

New research from California Institute of Technology headed by Anupama Thubagere and Lulu Qian built robots from DNA and programmed them to sort and deliver molecules to a specified location. These robots can potentially transform the drug delivery field to how body fights infections to how microscopic measurements are made. The dominant premise of DNA robots is that rather than creating molecular devices from scratch, we can use the power of molecular machinery by building microscopic-size robots and send them to places that are then impossible to reach, such as a cell or a hard-to-reach cancerous tumor. These robots demonstrated the ability to perform simple tasks, however this latest effort ramped up a path by programming DNA robots to perform a cargo‐sorting task and possibly many other tasks.

Each robot was built from a single-stranded DNA molecule of just 53 nucleotides equipped with “legs” for walking and “arms” for picking up objects. The robot are 20 nanometers tall and their walking strides measures six nanometers long, where one nanometer is a billionth of a meter. For the cargo, the researchers used two types of molecules, each being a distinct single-stranded piece of DNA. For the tests, the researchers placed the cargo onto a random location along the surface of a two-dimensional origami DNA test platform. The walking DNA robots moved in parallel along this surface, hunting for their cargo.

To see if a robot successfully picked up and dropped off the right cargo at the right location, the researchers used two fluorescent dyes to differentiate the molecules.

The researchers guess that each DNA robot took around 300 steps to complete its task, or roughly ten times more than in previous efforts. Though, more work is needed to figure out how these DNA robots perform under different environmental conditions. This new study suggests a worthwhile methodology for scientists to continue pursuing.

SOURCE

http://science.sciencemag.org/content/357/6356/eaan6558

 

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Targeting amyloidopathy

Larry H. Bernstein, MD, FCAP

LPBI

 

Targeting a rare amyloidotic disease through rationally designed polymer conjugates

Inmaculada Conejos–Sánchez, Isabel Cardoso, Maria J. Saraiva, María J.Vicent
Journal of Controlled Release 178 (2014), 95–100
Saraiva et al. discovered in 2006 a RAGE-based peptide sequence capable of preventing transthyretin (TTR) aggregate-induced cytotoxicity, hallmark of initial stages of an inherited rare amyloidosis known as Familial Amyloidotic Polyneuropathy (FAP). To allow clinical progression of this peptidic sequence as FAP treatment, a family of polymer conjugates has been designed, synthesised and fully characterised. This approach fulfills the strategies defined in the Polymer Therapeutics area as an exhaustive physico-chemical characterisation fitting activity output towards a novel molecular target that is described here. RAGE peptide acts extracellularly, therefore, nointracellular drug delivery was necessary. PEG was selected as carrier and polymer–drug linker optimisation was then carried out by means of biodegradable (disulphide) and non-biodegradable (amide) covalent bonds. Conjugate size in solution, stability under invitro and in vivo scenarios and TTR binding affinity through surface plasmon resonance (SPR) was also performed with all synthesised conjugates. In their in vitro evaluation by monitoring the activation of caspase-3 in Schwann cells, peptide derivatives demonstrated retention of peptide activity reducing TTR aggregates (TTRagg) cytotoxicity upon conjugation and a greater plasma stability than the parent free peptide. The results also confirmed that a more stable polymer–peptide linker (amide) is required to secure therapeutic efficiency.

Polymer therapeutics are well established as successful first generation nanomedicines for treatment of infectious diseases and cancer[1]. Polymer–protein, drug and aptamer conjugates are innovative chemical entities capable of improving bioactive compound properties and thus increasing efficacy and decreasing toxicity[2,3]. Design of second generation of conjugates is now focussing on improved polymer structures, polymer–based combination therapy and novel molecular targets with great potential to further progress the clinical importance of these unique technologies [4]. Novel conjugates for the treatment of neuropathological disorders are proposed in this study. Amyloidosis is well known in the form of Alzheimer’s and Parkinson’s disease, but the target disease here is a rarer pathological disorder named familial amyloid polyneuropathy (FAP). FAPs constitute an important group of inherited amyloidosis diseases, and one of the most commonFAPs is caused by a mutated protein called transthyretin (TTR), which forms amyloid deposits, mainly in the peripheral nervous system [5]. The aggregation cascade of this mutated protein, produces a TTR aggregate (TTRagg) able to trigger neurodegeneration through engagement with the receptor-for-advanced-glycation-end-products (RAGE) which is present on peripheral neurons. RAGE signalling has been defined to be involved in many human pathologies such as Alzhehimer’s disease, diabetes and ageing, among others. This receptor is also up-regulated in tissues fromFAP patients [6]. The secreted RAGE form, named soluble RAGE (sRAGE), acts as a decoy to trap ligands and prevent interaction with cell surface receptors. sRAGE was shown to have important inhibitory effects in several cell cultures and transgenic mouse models, in which it prevented or reversed full-length RAGE signalling.

Saraiva et al. [7] discovered a specific peptidic sequence (named RAGE peptide) that is able to suppress TTRagg-induced cytotoxicity in cell culture. A reduced version of that peptide was proved to maintain the activity and the affinity of the initial peptide. The final peptide (compound A) contains 6 amino acids and responds to the sequence (from N to C terminus): YVRVRY. Although this provides an opportunity to design novel therapeutics for FAP treatment, peptide therapeutics themselves display well known challenges for in vivo use, e.g. low stability, poor pharmacokinetics and potential immunogenicity. Moreover the RAGE peptide demonstrates low solubility in plasma limiting its potential for i.v.administration.

……

Herein, novel specific nanoconjugates for the treatment of amyloidosis, and in particular familial amyloidotic polyneuropathy are reported. Apart from the research reported by Prof Arima et al. [22] using a hepatocyte-targeted FAP siRNA complex with lactosylated dendrimer (G3)/α-cyclodextrin(Lac-α-CDE(G3)), no other type of polymer therapeutic has been reported up to now for the treatment of this chronic degenerative family of diseases. Our rational design started from an active biomolecule of peptidic nature (RAGE peptide) that recognises the TTR prefibrillar aggregates responsible to promote cell death in FAPpatients [7]. The clinical progress of this promising inhibitor was masked by the well-known limitations of peptides, such as low solubility, low stability and possible immunogenicity. PEGylation through various linking strategies was successfully accomplished here as a solution for the named drawbacks, using a systematic approach to maintain peptide activity and receptor binding specificity. The data relating toTTR binding affinity, conjugate linker stability and the conjugate size distribution in solution of PEG– RAGE peptide conjugates indicate that the conjugates containing amide linkers have the greatest potential for further development as FAP inhibitors. Moreover, this novel conjugate has promising possibilities as a FAP therapeutic to be used alone in the early stages of the disease or as part of rationally designed combination therapy [23,24]. Preliminary in vivo studies (biodistribution) are shown in the supporting information demonstrating the enhanced plasma stability of the peptide upon conjugation (Fig.5S) , showing nospecific accumulation in any organ and renal excretion. More exhaustive in vivo experiments are currently ongoing with selected conjugates.

 

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Medical Applications of Nano Magnetite

Author: Danut Dragoi, PhD

Nano magnetite refers to small crystals of Fe3O4 in nano-metric range that preserves some specific magnetic properties of the magnetite bulk crystal such as the magnetism at saturation, Curie temperature, coercive magnetic force, hysteresis loop, etc. A discussion of medical applications of nano-magnetic particles is shown in here.

Opportunities for magnetite nanoparticles to be effectively incorporated into environmental contaminant removal and cell separation ([1] Honda et al., 1998;[2] Ebner et al.,1999; [3] Rikers et al., 1998; [4] Navratil, 2003), magnetically guided-drug delivery (Roger et al., 1999), magnetocytolysis ([5] Roger et al., 1999), sealing agents (liquid O-rings) ([6] Enzel et al., 1999), dampening and cooling mechanisms in loudspeakers ([6] Enzel et al., 1999), and contrasting agents for magnetic resonance imaging (MRI) ([7] Schütt, 2004). Advancement of synthesis and stabilization procedures towards production of uniformly sized, dispersed (potentially embedded) magnetite nanoparticles has clearly inspired creative imagination and application in various fields. The following subsections address two topics, magnetic guided drug delivery and magnetic resonance tomography which  helps us  better understanding the capabilities offered by magnetite nanoparticles.

Magnetically Guided Drug Delivery

Ferrofluids containing encapsulated (with biologically compatible surface chemistries) magnetite nanoparticles, as described above, can be employed for drug delivery to specific locations. Exploitation of superparamagnetic magnetization of magnetite nanoparticles allows for “magnetic dragging” of internal (present in bloodstream or elsewhere) magnetite nanoparticles carrying DNA, enzymes, drugs to target-areas. Similarly, biological effectors, which are proteins (containing DNA specific to target cells) incorporated into encapsulated nanoparticle surface functionality, allow for target cell specificity. Once biological effector carrying magnetic nanoparticles bind to target-cells, the applied magnetic field is fluctuated (approximately 1 MHz) causing magnetocytolysis, or cell destruction, which eliminates target-cells. Similarly, after being dragged to target areas, magnetocytolysis of encapsulated nanoparticles can release drugs. Research towards these ends is currently being heavily investigated as potential for novel drug/cancer treatment abounds. ([5] Roger et al., 1999). Picture below shows schematically drug-loaded magnetic nanoparticles targeting for tumor therapy in which the magnetic nanoparticles are noninvasively moved toward the target.

Drug loaded NanoParicles

Image SOURCE:https://books.google.com/books?hl=en&lr=&id=oX32CwAAQBAJ&oi=fnd&pg=PA425&ots=1EDRtu7mDx&sig=fYjckTZEyXCkOBb4sjRAuWSR_U4#v=onepage&q&f=false

Magnetic Resonance Tomography

Magnetic Resonance Tomography (MRT) permits noninvasive visualization of cross-sectional images of the human body, tissues, and organs ([7] Schütt, 2004). The MRT technique provides better tissue resolution than traditional radiation based technologies; with addition of contrasting agents, this resolution can be further enhanced ([8] Shao et al., 2005). Magnetite nanoparticles (in ferrofluid form) are powerful contrasting agents due to their paramagnetic magnetization. Ferrofluid physico-morphosis under magnetic field Blaney 65 Human bloodstreams readily reject the nanoparticle colloidal solution, which quickly passes into the liver ([8] Shao et al., 2005). Consequently, ferrofluids have thus far only been useful in distinguishing between healthy and malignant liver cells. This limitation can be overcome through functionalization of magnetite nanoparticles with various ligands that allows for organ-specific transport; therefore, MRT imaging of various bodily organs can be possible. Furthermore, polymeric (i.e., polyethylene oxide – PEO) coating of functionalized magnetite particles permits ferrofluids longer bloodstream retention. ([7] Schütt, 2004) PEO coatings are applied through magnetite interaction with copolymer PEO-polypeptide; polypeptides interact with the positively charged magnetite surface and provide nanoparticle masking to allow longer bloodstream residence. These coated magnetite nanoparticles could also be employed as extremely efficient capsules for drug delivery systems, which are discussed by ([7] Schütt, 2004).

References

[1] Honda H, Kawabe A, Shinkai M, and Kobayashi T (1998). Development of chitosan-conjugated magnetite for magnetic cell separation. Journal of Fermentation and Bioengineering 86, 191-196

[2] Ebner AD, Ritter JA, Ploehn HJ, Kochen RL, and Navratil JD (1999). New magnetic field-enhanced process for the treatment of aqueous wastes. Separation Science and Technology 34, 1277-1300

[3] Rikers RA, Voncken JHL, and Dalmijn WL (1998). Cr-polluted soil studied by high gradient magnetic separation and electron probe. Journal of Environmental Engineering 124, 1159-1164

[4] Navratil JD (2003). Adsorption and nanoscale magnetic separation of heavy metals from water. U.S. EPA workshop on managing arsenic risks to the environment: characterization of waste, chemistry, and treatment and disposal. Denver, CO

[5] Roger J, Pons JN, Massart R, Halbreich A, and Bacri JC (1999). Some biomedical applications of ferro fluids. Eur. Phys. J. AP 5, 321-325

[6] Enzel P, Adelman N, Beckman KJ, Campbell DJ, Ellis AB, Lisensky GC (1999). Preparation of an aqueous-based ferrofluid. J. Chem. Educ. 76, 943-948

[7] Schütt D (2004). Magnetite colloids for drug delivery and magnetic resonance imaging. Institute Angewandte Polymerforschung: thesis Selim MS, Cunningham LP, Srivastava R, Olson JM (1997). Preparation of nano-size magnetic gamma ferric oxide (γ-Fe2O3) and magnetite (Fe3O4) particles for toner and color imaging applications. Recent Progress in Toner Technologies, 108- 111

[8] Shao H, Lee H, Huang Y, Kwak BK, and Kim CO (2005). Synthesis of nano-size magnetite coated with chitosan for MRI contrast agent by sonochemistry. Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International, 461-462

https://books.google.com/books?hl=en&lr=&id=oX32CwAAQBAJ&oi=fnd&pg=PA425&ots=1EDRtu7mDx&sig=fYjckTZEyXCkOBb4sjRAuWSR_U4#v=onepage&q&f=false

 

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Novel Macromolecular IV to Oral Delivery Conversion Pathway: Anti-thrombolytic post-surgical – Catalent OptiGel Bio™ Technology

Reporter: Aviva Lev-Ari, PhD, RN

Case Study

OptiGel BioTechnology Enables IV to Oral Therapy Conversion

Executive Summary

An early-stage biotechnology company had developed a novel macromolecular intravenous (IV) therapy for an anti-thrombolytic post-surgical indication. While the therapy had shown complete absorption via IV, the dose form was not ideal due to a number of factors including manufacturing costs, compliance, and ease of use, as well as as well as the long term treatment requirements. This case study demonstrates how Catalent OptiGel Bio™ technology can provide a pathway for an IV to oral delivery conversion, resulting in enhanced therapies for patients.

The Challenges

Though soluble, the macromolecule presented a number of permeability challenges, which hindered delivery of an active therapeutic dose across the lumen of the small intestine to achieve the desired therapeutic effect.

*Salamat-Miller N et al. , Pharmaceutical Research, 2005, 22(2):245-254

By incorporating OptiGel Bio™ technology and our formulation expertise, an optimized oral therapy was developed combining permeation enhancement and targeted delivery.

physiochemical properties High molecular weight (>2500 Da)Strong negative charge*

Rigid, inflexible geometry*

targeted delivery Functional API must be delivered to the small intestine in order to achieve bioavailability
permeability Mucus layer physical barrierRandom and limited transcellular pathways

“Fence and gate” function of tight junctions

pharmacokinetic profile Oral delivery must reach exposure within therapeutic range

The Catalent Solution

enhanced permeability The first challenge to overcome in development was enhancing the permeability of the macromolecule. A stepwise screening approach utilizing both in vitro and in vivo models yielded lead formulation candidates for further evaluation.

The Catalent Solution

https://kapost-files-prod.s3.amazonaws.com/uploads/direct/1382388405-22-3748/274-01_CaseStudy_OptiGelBio.pdf

enhanced permeability The first challenge to overcome in development was enhancing the permeability of the macromolecule. A stepwise screening approach utilizing both in vitro and in vivo models yielded lead formulation candidates for further evaluation.

Conclusion

Using OptiGel Bio™ technology, we overcame the challenges traditionally associated with the oral delivery of macromolecules and enabled conversion from an IV to a more efficient, more convenient and less invasive oral dose form while maintaining an effective pK profile. Through a multi-step drug delivery screening process and our OptiGel Bio™ technology, we can enable enhanced therapies—resulting in better treatments and more value for innovators, healthcare professionals and patients.

SOURCE

https://kapost-files-prod.s3.amazonaws.com/uploads/direct/1382388405-22-3748/274-01_CaseStudy_OptiGelBio.pdf

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