Thermal Analyses of Cyclodextrin Complexes

Evaluation of the In Vitro Stability of Stimuli-Sensitive Fatty Acid-Based Microparticles for the Treatment of Lung Cancer

The fatty acid-based microparticles containing iron oxide nanoparticles and paclitaxel (PAX) are a viable proposition for the treatment of lung cancer. The microparticles inhaled as a dry powder can be guided to selected locations using an external magnetic field, and when accumulated there, the active compound release can be triggered by local hyperthermia. However, this general strategy requires that the active compound is released from microparticles and can reach the targeted cells before microparticles are removed. Isothermal titration calorimetry was used to demonstrate that the components of microparticles were released and transferred to albumins and lipid bilayers. The morphology of the measured particulates was studied with scanning electron microscopy and dynamic light scattering. To determine the cytotoxicity of microparticles, cell culture studies were done. It has been shown that the transfer efficiency depends predominantly on the fatty acid composition of microparticles, which, together with the active ingredient, accumulate predominantly in membrane structures after being released from microparticles and before entering the cytoplasm. The release process is sufficient; hence, paclitaxel-loaded microparticles effectively suppressed the proliferation of A549 human lung epithelial cells of malignant origin (IC₅₀ values for both lauric acid-based and myristic/palmitic-based microparticles containing paclitaxel were below 0.375 μg/mL), while reference microparticles were noncytotoxic.

Fatty acid profile of Romanian's common bean (Phaseolus vulgaris L.) lipid fractions and their complexation ability by β-cyclodextrin

The goal of the present study was the evaluation of the fatty acid (FA) profile of lipid fraction from dry common beans (Phaseolus vulgaris L.) (CBO) harvested from North-East (NE) and South-West (SW) of Romania and to protect against thermal and oxidative degradation of the contained omega-3 and omega-6 polyunsaturated fatty acid (PUFA) glycerides by β-cyclodextrin (β-CD) nanoencapsulation, using kneading method. The most abundant FAs in the CBO samples were PUFAs, according to gas chromatography-mass spectrometry (GC-MS) analysis. Linoleic acid (methyl ester) was the main constituent, having relative concentrations of 43.4 (±1.95) % and 35.23 (±0.68) % for the lipid fractions separated from the common beans harvested from the NE and SW of Romania, respectively. Higher relative concentrations were obtained for the omega-3 α-linolenic acid methyl ester at values of 13.13 (±0.59) % and 15.72 (±0.30) % for NE and SW Romanian samples, respectively. The omega-3/omega-6 ratio consistently exceeds the lower limit value of 0.2, from where the PUFA glyceride mixture is valuable for the human health. This value was 0.32 (±0.02) for the NE samples and significantly higher for the CBO-SW samples, 0.51 (±0.01). These highly hydrophobic mixtures especially consisting of PUFA triglycerides provide β-CD complexes having higher thermal and oxidative stability. Kneading method allowed obtaining β-CD/CBO powder-like complexes with higher recovery yields of >70%. Thermal analyses of complexes revealed a lower content of hydration water (3.3–5.8% up to 110°C in thermogravimetry (TG) analysis and 154–347 J/g endothermal effect in differential scanning calorimetry (DSC) analysis) in comparison with the β-CD hydrate (12.1% and 479.5–480 J/g, respectively). These findings support the molecular inclusion process of FA moieties into the β-CD cavity. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analysis reveals the formation of the β-CD/CBO inclusion complexes by restricting the vibration and bending of some bonds from the host and guest molecules. Moreover, powder X-ray diffractometry (PXRD) analysis confirm the formation of the host-guest complexes by modifying the diffractograms for β-CD/CBO complexes in comparison with the β-CD and β-CD + CBO physical mixtures. A significant reduction of the level of crystallinity from 93.3 (±5.3) % for β-CD to 60–60.9% for the corresponding β-CD/CBO complexes have been determined. The encapsulation efficiency (EE), the profile of FAs, as well as the controlled release of the encapsulated oil have also been evaluated. The EE was >40% in all cases, the highest value being obtained for β-CD/CBO-SW complex. The SFA content increased, while the unsaturated FA glycerides had lower relative concentrations in the encapsulated CBO samples. It can be emphasized that the main omega-3 FA (namely α-linolenic acid glycerides) had close concentrations in the encapsulated and raw CBOs (13.13 (±0.59) % and 14.04 (±1.54) % for non-encapsulated and encapsulated CBO-NE samples, 15.72 (±0.30) % and 12.41 (±1.95) % for the corresponding CBO-SW samples, respectively). The overall unsaturated FA content significantly decreased after complexation (from 19.03–19.16% for the raw CBOs to 17.3–17.7% for encapsulated oils in the case of MUFAs, and from 55.7–58.8% to 35.13–43.36% for PUFAs). On the other hand, the omega-3/omega-6 ratio increased by β-CD nanoencapsulation to 0.51 (±0.07) and 0.76 (0.26) for β-CD/CBO-NE and β-CD/CBO-SW complexes, respectively. As a conclusion, the lipid fractions of the Romanian common beans are good candidates for β-CD complexation and they can be protected against thermal and oxidative degradation in common beans based food products such as functional foods or food supplements using natural CDs.

Tumor-Targeting NIRF NanoGUMBOS with Cyclodextrin-Enhanced Chemo/Photothermal Antitumor Activities

The near-infrared fluorescent (NIRF) dye, IR780, is recognized as a promising theranostic agent and has been widely investigated for imaging, chemotherapeutic, and phototherapeutic applications. However, its poor photostability and nonselective toxicities toward both cancer and normal cells limit its biological applications. Herein, we introduce the use of GUMBOS (a group of uniform materials based on organic salts) developed through counter-anion exchange with IR780 and subsequent nanomaterials (nanoGUMBOS) formed by complexation with cyclodextrin (CD) for enhanced chemo/photothermal therapy. Such CD-based nanoGUMBOS display improved aqueous stability, photostability, and photothermal effects relative to traditional IR780. The examination of in vitro cytotoxicity reveals that CD-based nanoGUMBOS are selectively toxic toward cancer cells and exhibit synergistically enhanced cytotoxicity toward cancer cells upon NIR laser irradiation. Additionally, in vivo NIRF imaging demonstrated selective accumulation of these nanoGUMBOS within the tumor site, indicating tumor-targeting properties. Further in vivo therapeutic study of these CD-based nanoGUMBOS suggests excellent chemo/photothermal antitumor effects. Using these studies, we herein demonstrate a promising strategy, via conversion of IR780 into nanoGUMBOS, that can be used for improved theranostic cancer treatment.