Dual drug-loaded nanotherapeutics can play an important role against the drug resistance and side effects of the single drugs. Doxorubicin and sorafenib were efficiently co-encapsulated by tailor-made poly([R,S]-3-hydroxybutyrate) (PHB) using an emulsion–solvent evaporation method. Subsequent poly(ethylene glycol) (PEG) conjugation onto nanoparticles was applied to make the nanocarriers stealth and to improve their drug release characteristics. Monodisperse PHB–sorafenib–doxorubicin nanoparticles had an average size of 199.3 nm, which was increased to 250.5 nm after PEGylation. The nanoparticle yield and encapsulation efficiencies of drugs decreased slightly in consequence of PEG conjugation. The drug release of the doxorubicin was beneficial, since it was liberated faster in a tumor-specific acidic environment than in blood plasma. The PEG attachment decelerated the release of both the doxorubicin and the sorafenib, however, the release of the latter drug remained still significantly faster with increased initial burst compared to doxorubicin. Nevertheless, the PEG–PHB copolymer showed more beneficial drug release kinetics in vitro in comparison with our recently developed PEGylated poly(lactic-co-glycolic acid) nanoparticles loaded with the same drugs.

The bioavailability of the antihypertensive drug valsartan can be enhanced by various microencapsulation methods. In the present investigation, valsartan-loaded polymeric nanoparticles were manufactured from Eudragit^® RLPO using an emulsion–solvent evaporation method. Polyvinyl alcohol (PVA) was found to be a suitable stabilizer for the nanoparticles, resulting in a monodisperse colloid system ranging in size between 148 nm and 162 nm. Additionally, a high encapsulation efficiency (96.4%) was observed. However, due to the quaternary ammonium groups of Eudragit^® RLPO, the stabilization of the dispersion could be achieved in the absence of PVA as well. The nanoparticles were reduced in size (by 22%) and exhibited similar encapsulation efficiencies (96.4%). This more cost-effective and sustainable production method reduces the use of excipients and their expected emission into the environment. The drug release from valsartan-loaded nanoparticles was evaluated in a two-stage biorelevant dissolution set-up, leading to the rapid dissolution of valsartan in a simulated intestinal medium. In silico simulations using a model validated previously indicate a potential dose reduction of 60–70% compared to existing drug products. This further reduces the expected emission of the ecotoxic compound into the environment.

Valsartan is an antihypertensive drug used primarily orally, however, due to its hydrophobic nature it has got low bio-availability thus requiring higher dosage/frequency and causing more side effects. The aim of our work was to prepare valsartan-loaded nanoparticles by using ethyl cellulose and poly(methyl methacrylate) polymers which can be administered orally and to investigate the preparation conditions and their significance as potential drug carriers for valsartan delivery by in vitro release studies. Ethyl cellulose and poly(methyl methacrylate) polymers were used for the preparation of nanoparticles by single emulsion-solvent evaporation technique. The formation of drug-loaded nanoparticles was designed by experimental design for size and encapsulation efficiency, in addition the prepared nanosuspensions were nano spray dried in order to gain a powder form that is easy to handle and store. Both of the nano spray dried formulations had an amorphous structure in contrast to the pure drug according to differential scanning calorimetry and X-ray diffraction analysis, which can be advantageous in drug absorption. The originally processed ethyl cellulose-valsartan nanoparticles increased the solubility of the drug in the model intestinal medium, while poly(methyl methacrylate)-valsartan nanoparticles enabled substantially prolonged drug release. The release kinetics of both types of nanoparticles could be described by the Weibull model.

Salt hydrates are low-cost, readily available PCMs (phase change materials). As a core material for encapsulation the salt agglomerates can be prepared by spherical agglomeration, a well-known method to produce drug loaded microspheres in the pharmaceutical industry, but not used for PCM formulation. The two basic mechanisms in spherical crystallization are spherical agglomeration (SA) and the quasi emulsion solvent diffusion (QESD) processes. The spherical agglomerates of aluminium potassium sulfate dodecahydrate (potash alum dodecahydrate), a highly water soluble material, were produced by spherical crystallization technique in four different solvent systems. In water (good solvent)–ethanol–dichloromethane (poor solvent) ternary solvent system the agglomeration takes place by the SA mechanism. In water–ethanol–n-hexane, water–ethanol and water–isopropyl alcohol solvent systems spherical particles were produced by the QESD method. Both procedures were proved to be feasible for the preparation of spherical salt hydrate particles as core material for microencapsulation. This method gives important basis to produce phase change materials from suitable salt hydrates. The potash alum content in the spherical agglomerates was analysed by conductivity and thermogravimetric measurements and their composition by XRD. Volume weighted mean diameters (D(4,3)) of the microparticles were 66 μm, 79 μm, 89 μm, and 684 μm formed in water–ethanol–n-hexane, water–ethanol, water–isopropyl alcohol, and water–ethanol–dichloromethane solvent system, respectively. Potash alum dodecahydrate is a double salt. Due to its different solubility in the four different solvent systems it crystallized out not only as potash alum, but also in other salt forms. The enthalpy changes of spherical agglomerates produced from different solvent systems were increased proportionally with potash alum contents.

Octyl laurate phase change material (PCM) was microencapsulated by calcium alginate for eco-friendly low temperature energy storage. The PCM microcapsules were prepared by repeated interfacial coacervation followed by crosslinking method. In order to enhance the antibacterial properties of the as prepared capsules, the calcium alginate shell was functionalized by Ag nanoparticles. Calcium alginate-octyl laurate microcapsules possessed high latent heat of fusion values (130.8 and 128.6 J g⁻¹ on melting and cooling, respectively) which did not significantly change when Ag nanoparticles were entrapped in the shell (127.5 and 125.2 J g⁻¹ for melting and freezing enthalpy changes). Based on these values 71.0 and 69.0% maximal PCM content in the microcapsules were determined by the differential scanning calorimetry method. Both of the Ag-loaded and unloaded calcium alginate-octyl laurate PCM capsules maintained the high heat storing capacity after 250 warming and cooling cycles, which proved they did not suffer from leakage after the accelerated thermal test.

Anthocyanidins, the aglycons of anthocyanins, are known, beyond their function in plants, also as compounds with a wide range of biological and pharmacological activities, including cytostatic effect against various cancer cells. The nature and position of the substituents in the flavylium cation is essential for such biological properties, as well as the equilibrium between the multistate of the different chemical species that are generated by the flavylium cation, including quinoidal base, hemiketal, and cis- and trans-chalcones. In this work, eight new flavylium derivatives were synthesized, characterized for confirmation of the structure by FT-IR and 2D-NMR, and investigated in vitro as possible cytostatic compounds against HCT116 and HepG2 cancer cells. The most active two compounds were explored for their halochromic properties that can influence the biological activity and subjected to molecular encapsulation in β-cyclodextrin derivatives in order to increase their solubility in water and bioavailability. The anticancer effect was influenced by the position (6-, 7-, or 8-) of the methoxy group in the β-ring of the methoxy-4′-hydroxy-3′-methoxyflavylium cation, while the study of the halochromic properties revealed the important role played by the chalcone species of the pH-dependent multistate in both the uncomplexed and inclusion complex forms of these anthocyanidins.