Drug-eluting stents have proven to be effective in reducing the risk of late restenosis. In order to achieve a controlled and prolonged release of the antiproliferative agent, current drug-eluting stents utilise various biodegradable as well as non-erodible polymeric blends to coat the stent surface and to serve as drug carriers. The utilisation of polymeric compounds in current drug-eluting stents may eventually limit their performance as well as their clinical applicability due to the potential induction of undesirable local reactions. The development of alternative, polymer-free drug carriers has the potential to overcome some of the limitations of current drug-eluting stent formulations. Moreover, improvements in drug carriers may also result in an expansion of the technological possibilities for other intravascular drug delivery systems, such as metal-free or even implant-free solutions. This article describes the structure and the preclinical validation profile of a novel phospholipid encapsulated sirolimus nanocarrier, used as a coating in two formulations: a coronary stent-plus-balloon system and a stand-alone balloon catheter. The nanoparticles provided a stable, even and homogenous coating to the devices in both formulations. Dose-finding studies allowed the most appropriate identification of the best nanoparticle structure associated with an extremely efficient transfer of drug to all layers of the vessel wall, achieving high tissue concentrations that persisted days after the application, with low systemic drug leaks.

High-performance polymers based on aromatic rings are desirable not only because of the high primary bond strengths, but also because their rigid (stiff) polymer chains offer increased resistance to deformation and thermal softening. The choice of s-triazine nucleus is based on its high thermal stability derived from its molecular symmetry and aromaticity. It is well known that s-triazine is heat resistant. Modification of monomer structures by introduction of aromatic pendent groups or heterocyclic rings into the polymer backbone provides good solubility and thermal stability. A new set of polyamides with —CO—NH— groups were synthesized by the Yamazaki’s phosphorylation reaction 2-(morpholino)-4,6-bis (6-napthoxy-2-carboxy)-s-triazine with various aromatic diamines. The polyamides had inherent viscosities in the range 0.549—0.685 dL g-1 in dimethylformamide at room temperature (30 °C) and density 1.135—1.208 g cm - 3 . All the polyamides showed good thermal stability and most of them were readily soluble at room temperature in polar solvents such as N,N-dimethylacetamide, 1-methyl-2-pyrrolidone and dimethylformamide. Polyamides were synthesized successfully with the favourable properties of higher thermal stability along-with good processibility.

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Background: Magic Touch TM is a sirolimus-based nano-carrier eluting balloon. This study aimed to find the excipient:drug ratio with the greatest capacity to inhibit neointimal proliferation 28 days after the use of this balloon and following bare-metal stenting in porcine coronary arteries. Methods: Fourteen domestic pigs who received coronary bare-metal stent implants followed by dilation (60 seconds) using balloons with excipient:sirolimus ratios of 1:1, 0.5:1, 0.25:1, and 1:0 or a control balloon were evaluated. After 28 days, neointimal hyperplasia was assessed by optical coherence tomography and histopathology. Results: The rate of neointimal hyperplasia as assessed by optical coherence tomography and histomorphometry was 32.2% and 35.

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