Slawomir Kazmierski

Recent progress in solid-state NMR studies of drugs confined within drug delivery systems.

Recent progress in the application of solid-state NMR (SS NMR) spectroscopy in structural studies of active pharmaceutical ingredients (APIs) embedded in different drug carriers is detailed. This article is divided into sections. The first part reports short characterization of the nanoparticles and microparticles that can be used as drug delivery systems (DDSs). The second part shows the applicability of SS NMR to study non-steroidal anti-inflammatory drugs (NSAIDs). In this section, problems related to API-DDS interactions, morphology, local molecular dynamics, nature of inter- or intramolecular connections, and pore filling are reviewed for different drug carriers (e.g. mesoporous silica nanoparticles (MSNs), cyclodextrins, polymeric matrices and others). The third and fourth sections detail the recent applications of SS NMR for searching for antibiotics and anticancer drugs confined in zeolites, MSNs, amorphous calcium phosphate and other carriers.

Chapter Two - Recent Progress in the Solid-State NMR Studies of Short Peptides: Techniques, Structure and Dynamics

In this chapter, progress in the solid-state NMR studies of short peptides published during the last 10 years is reviewed. The chapter is divided into sections. After the preface, Section 2 presents a comprehensive introduction to the modern NMR techniques which are used in structural studies of peptides. Techniques employing fast magic-angle spinning with sample rotation over 40 kHz are highlighted. Two-dimensional homo- and heteronuclear correlation experiments with inverse detection (based on J and dipolar interactions) are discussed for spin I = 1/2 nuclei as well as for quadrupolar nuclei (I > 1/2). Section 3 reviews methodologies which are employed to analysis of molecular dynamics of peptides in the solid state. Tools for inspection of local molecular motions in different time scales such as measurements of relaxation times, chemical shift anisotropies, line-shape analysis of static spectra and heteronuclear dipolar couplings obtained by means of recoupling sequences are shortly discussed. Section 4 is devoted to problem of polymorphism and solvatomorphism. Special attention is paid to NMR study of hydrates and their solid-state transformations. In Section 5, the complementarity of theoretical (GIPAW, GIAO, ONIOM) and NMR methods in structural analysis of peptides in the solid state is reviewed. The attention is paid to the assignment problem, refinement of crystal and molecular structure for disordered peptides and correlations between theoretical and experimental shielding parameters for systems which are under fast exchange regime.

Chlorambucil labelled with the phenosafranin scaffold as a new chemotherapeutic for imaging and cancer treatment

Here we report the first of the phenosafranin-chlorambucil conjugate as a new type of a chemotherapeutic agent suitable for dual detection methods (spectrophotometric and fluorescence) in imaging systems and cancer treatment. The synthetic cationic dye (3,7-diamino-5-phenylphenazinium chloride) is used as a fluorescent light-triggered scaffold that acts as a carrier for an anti-cancer drug. The chlorambucil was attached covalently via amide bonds to the bifunctional fluorophore, which facilitates tracking with visible light. Our studies revealed that the new photosensitive compound exhibits improved intrinsic activity in vitro in HeLa cells culture experiments; thus it could be a potential anti-cancer candidate in theranostic drug-delivery systems. In light of the urgent need for in vivo monitoring of the biodistribution of anti-cancer drugs, this strategy for the synthesis of innovative conjugates based on the phenosafranin backbone offers a promising possibility for drug control in anti-cancer therapy and diagnosis. This aspect makes the phenosafranin-chlorambucil conjugate unique among currently available biomarkers.

Diffusion-controllable biomineralization conducted in situ in hydrogels based on reversibly cross-linked hyperbranched polyglycidol

We present biocompatible hydrogel systems suitable for biomineralization processes based on hyperbranched polyglycidol cross-linked with acrylamide copolymer bearing carbonyl-coordinated boronic acid. At neutral pH, diol functional groups of HbPGL react with boronic acid of polyacrylamide to generate 3D network in water by the formation of boronic ester cross-links. The dynamic associative/dissociative characteristics of the cross-links makes the network reversible. The presented hydrogels display self-healing properties and are injectable, facilitating gap filing of bone tissue. The 1H HR MAS DOSY NMR studies reveal that acrylamide copolymer plays the role of the network framework, whereas HbPGL macromolecules, due to their compact structure, move between reactive sites of the copolymer. The influence of the copolymer macromolecules entanglements and overall polymer concentrations on macromolecules mobility and stress relaxation processes is investigated. The process of hydrogel biomineralization results from hydrolysis of 1-naphthyl phosphate calcium salt catalyzed by encapsulation in hydrogel alkaline phosphatase. The environment of the hydrogel is entirely neutral toward the enzyme. However, the activity of alkaline phosphatase encapsulated within the hydrogel structure is diffusion-limited. In this article, based on the detailed characteristics of three model hydrogel systems, we demonstrate the influence of the hydrogel permeability on the encapsulated enzyme activity and calcium phosphate formation rate. The 1H HR MAS DOSY NMR is used to monitor diffusion low-molecular weight compound within hydrogels, whereas 31P HR MAS NMR facilitates monitoring of the progress of biomineralization in situ within hydrogels. The results show a direct correlation between low molecular diffusivity in hydrogels and network dynamics. We demonstrate that the morphology of in situ-generated calcium phosphate within three model HbPGL/poly(AM-ran-APBA) hydrogels of different low molecular permeability varies substantially from sparsely deployed large, well-defined crystals to an even distribution within the polymers polycrystalline continuous network.