Avi Domb

A. Basu and A.J. Domb. 2020. “Ion Exchange Nanoparticles for Ophthalmic Drug Delivery.” Bioconjugate Chemistry. Publisher's Version Abstract
We report here on ion-exchange polymeric nanoparticles from a linear copolymer of maleic anhydride methyl vinyl ether esterified with 30% octadecanol. The side chains for the polymer structure were optimized through metadynamics simulations, which revealed the use of octadecanol esters generates ideal free energy surfaces for drug encapsulation and release. Nanoparticles were synthesized using a solvent evaporation-precipitation method by mixing the polymer solution in acetone into water; upon acetone evaporation, a nanodispersion with an average particle size of ∼150 nm was obtained. Gentamicin sulfate, possessing five amino groups, was spontaneously entrapped in the nanocarrier by ionic interactions. Encapsulation efficiency increases significantly with the increase in pH and ionic strength. In vivo results demonstrate high gentamicin (GM) content in the enteric chamber (AUC 8207 ± 1334 (μg min)/mL) compared to 3% GM solution (AUC 2024 ± 438 (μg min)/mL). The formulation was also able to significantly extend the release of gentamicin when applied to rabbit cornea. These anionic nanoparticles can be used for extended-release of other cationic drugs. © 2020 American Chemical Society.}, funding_text 1=his work was supported by a grant from Teva Pharm. Industries, affiliated with the David Bloom Center for Pharmacy and The Alex Grass Center for Drug Design. A.B. would like to thank the planning and budget commission (PBC) of Israel for providing Postdoctoral Fellowships.
M. Haim Zada, A. Kumar, O. Elmalak, E. Markovitz, R. Icekson, and A.J. Domb. 2020. “In vitro and in vivo degradation behavior and the long-term performance of biodegradable PLCL balloon implants.” International journal of pharmaceutics, 574, Pp. 118870. Publisher's Version Abstract
Biodegradable poly(l-lactide-co-ε-caprolactone) (PLCL) are used to prepare inflatable balloon implants in treating rotator-cuff injuries and tissue separation. These balloon implants act as a temporary spacer for tissues, while reducing pain and allowing rehabilitation after surgery. It is essential to ensure that each balloon fulfill two requirements after implantation: (1) display a well-defined degradation profile, and (2) remain unaffected by premature rapture or leakage. Storage also affects the stability of a polymer-based implant. Since the balloons are implanted into humans, it is essential to understand their in vitro and in vivo degradation along with their physicochemical properties. It is unpredictable if balloon storage on their performance. Therefore, the in vitro and in vivo degradation behavior of PLCL balloons was examined during one year, and the information obtained was used to correlate reliability under prolonged storage conditions. We investigated changes in weight, melting temperature (Tm), molecular weight distribution (Mw, Mn and PDI), crystallinity (Χ), optical activity [α], and inherent viscosity (η) of the balloons during the entire degradation time. We also examined the molecular properties of the balloons under annealing and extreme temperature conditions, such as the combined effect of temperature and humidity that simulate various storage conditions. We have concluded that degradation of the PLCL balloons is slow, and they remain stable during the test period. Results reveal that the balloons retain their molecular properties under long-term storage, annealing, and extreme temperature conditions. The balloons did not show any variation from reference samples, and they exhibited a constant stability profile even after shelf-storage of more than 3 years. These findings can serve as a case study for evaluating various other biodegradable materials. Copyright © 2019 Elsevier B.V. All rights reserved.
Activated T cells are pathological in various autoimmune and inflammatory diseases including Psoriasis, and also in graft rejection and graft-versus-host-disease. In these pathological conditions, selective silencing of activated T cells through physiological receptors they express remains a clinical challenge. In our previous studies we found that activation of dopamine receptors (DRs) in resting human T cells activates these cells, and induces by itself many beneficial T cell functions. In this study, we found that normal human T cells express all types of DRs, and that expression of D1R, D4R and D5R increases profoundly after T cell receptor (TCR) activation. Interestingly, DR agonists shift the membrane potential (Vm) of both resting and activated human T cells, and induces instantaneous T cell depolarization within 15 seconds only. Thus, activation of DRs in T cells depolarize these immune cells, alike activation of DRs in neural cells. The skin of Psoriasis patients contains 20-fold more D1R+ T cells than healthy human skin. In line with that, 25-fold more D1R+ T cells are present in Psoriasis humanized mouse model. Highly selective D1-like receptor agonists, primarily Fenoldopam (Corlopam) – a D1-like receptor agonist and a drug used in hypertension, induced the following suppressive effects on activated T cells of Psoriasis patients: reduced chemotactic migration towards the chemokine SDF-1/CXCL12; reduced dramatically the secretion of eight cytokines: tumor necrosis factor-α, interferon-γ, interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-8 and IL-10; and reduced three T cell activation proteins/markers: CD69, CD28 and IL-2. Next, we invented a novel topical/dermal Fenoldopam formulation, allowing it to be spread on, and providing prolonged and regulated release in, diseased skin. Our novel topical/dermal Fenoldopam: reduced secretion of the eight cytokines by activated human T cells; reduced IL-1β and IL-6 secretion by human lipopolysaccharide-inflamed skin; eliminated preferentially >90% of live and large/proliferating human T cells. Together, our findings show for the first time that both resting and activated T cells are depolarized instantaneously via DRs, and that targeting D1-like receptors in activated T cells and inflamed human skin by Fenoldopam, in Psoriasis, and potentially in other T cell-mediated diseases, could be therapeutic. Validation in vivo is required. © 2019 John Wiley & Sons Ltd
U. Bulbake, A. Singh, A.J. Domb, and W. Khan. 2019. “Therapeutic macromolecular iron chelators.” Current Medicinal Chemistry, 26, 2, Pp. 323-334. Publisher's Version Abstract
Iron is a key element for every single living process. On a fundamental level, targeting iron is a valuable approach for the treatment of disorders caused by iron overload. Utilizing iron chelators as therapeutic agents has received expanding consideration in chelation therapy. Approved low molecular weight (MW) iron chelators to treat iron overload may experience short half-lives and toxicities prompting moderately high adverse effects. In recent years, polymeric/macromolecular iron chelators have received attention as therapeutic agents. Polymeric iron chelators show unique pharmaceutical properties that are different to their conventional small molecule counterparts. These polymeric iron chelators possess longer plasma half-lives and reduced toxicities, thus exhibiting a significant supplement to currently using low MW iron chelator therapy. In this review, we have briefly discussed polymeric iron chelators and factors to be considered when designing clinically valuable iron chelators. We have also discussed applications of polymeric iron chelators in the diseases caused by iron overload associated with transfusional hemosiderosis, neurodegenerative disorders, malaria and cancer. With this, research findings for new polymeric iron chelators are also covered. © 2019 Bentham Science Publishers.
N.Y. Steinman and A.J. Domb. 2019. “Injectable pasty biodegradable polyesters derived from castor oil and hydroxyl-acid lactones.” Journal of Pharmacology and Experimental Therapeutics, 370, 3, Pp. 736-741. Publisher's Version Abstract
Pasty polymers offer a platform for injectable implants for drug delivery. A library of biodegradable pasty polymers was synthesized by bulk ring-opening polymerization of lactide, glycolide, trimethylene carbonate, or caprolactone using castor oil or 12-hydroxy stearic acid as hydroxyl initiators and stannous octoate as the catalyst. Some of the polymers behaved as Newtonian liquids. Pasty polymers of poly(caprolactone) and poly(trimethylene carbonate) were stable under physiologic conditions for over 1 month in vitro, whereas polymers of poly(lactic-co-glycolic acid) degraded within 10 days. These pasty polymers offer a platform for pasty injectable biodegradable carriers for drugs and fillers. Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics.