Time-of-flight secondary ion mass spectrometry study on the distribution of alendronate sodium in drug-loaded ultra-high molecular weight polyethylene

Luminescent Alendronic Acid-Conjugated Micellar Nanostructures for Potential Application in the Bone-Targeted Delivery of Cholecalciferol

Vitamin D, an essential micronutrient crucial for skeletal integrity and various non-skeletal physiological functions, exhibits limited bioavailability and stability in vivo. This study is focused on the development of polyethylene glycol (PEG)-grafted phospholipid micellar nanostructures co-encapsulating vitamin D3 and conjugated with alendronic acid, aimed at active bone targeting. Furthermore, these nanostructures are rendered optically traceable in the UV-visible region of the electromagnetic spectrum via the simultaneous encapsulation of vitamin D3 with carbon dots, a newly emerging class of fluorescents, biocompatible nanoparticles characterized by their resistance to photobleaching and environmental friendliness, which hold promise for future in vitro bioimaging studies. A systematic investigation is conducted to optimize experimental parameters for the preparation of micellar nanostructures with an average hydrodynamic diameter below 200 nm, ensuring colloidal stability in physiological media while preserving the optical luminescent properties of the encapsulated carbon dots. Comprehensive chemical-physical characterization of these micellar nanostructures is performed employing optical and morphological techniques. Furthermore, their binding affinity for the principal inorganic constituent of bone tissue is assessed through a binding assay with hydroxyapatite nanoparticles, indicating significant potential for active bone-targeting. These formulated nanostructures hold promise for novel therapeutic interventions to address skeletal-related complications in cancer affected patients in the future.

A Comparative Study of Ultrasmall Calcium Carbonate Nanoparticles for Targeting and Imaging Atherosclerotic Plaque

Atherosclerosis is a complex disease that can lead to life-threatening events, such as myocardial infarction and ischemic stroke. Despite the severity of this disease, diagnosing plaque vulnerability remains challenging due to the lack of effective diagnostic tools. Conventional diagnostic protocols lack specificity and fail to predict the type of atherosclerotic lesion and the risk of plaque rupture. To address this issue, technologies are emerging, such as noninvasive medical imaging of atherosclerotic plaque with customized nanotechnological solutions. Modulating the biological interactions and contrast of nanoparticles in various imaging techniques, including magnetic resonance imaging, is possible through the careful design of their physicochemical properties. However, few examples of comparative studies between nanoparticles targeting different hallmarks of atherosclerosis exist to provide information about the plaque development stage. Our work demonstrates that Gd (III)-doped amorphous calcium carbonate nanoparticles are an effective tool for these comparative studies due to their high magnetic resonance contrast and physicochemical properties. In an animal model of atherosclerosis, we compare the imaging performance of three types of nanoparticles: bare amorphous calcium carbonate and those functionalized with the ligands alendronate (for microcalcification targeting) and trimannose (for inflammation targeting). Our study provides useful insights into ligand-mediated targeted imaging of atherosclerosis through a combination of in vivo imaging, ex vivo tissue analysis, and in vitro targeting experiments.

Formulation and Evaluation of Niosomal Alendronate Sodium Encapsulated in Polymeric Microneedles: In Vitro Studies, Stability Study and Cytotoxicity Study

The aim of this study is to design and evaluate a transdermal delivery system for alendronate sodium (ALS) loaded with nanocarrier to improve its permeability and prolong its release. This is due to its low bioavailability, potential gastrointestinal side effects, and the special administration needed for the oral dosage form of ALS. When using the ether injection method, various niosomal formulations were produced. Size of the particles, polydispersity index (PDI), surface charge (ZP), drug entrapment efficiency (EE), and in vitro release were used to characterize the resulting niosomes. The size of niosomes ranged between 99.6 ± 0.9 and 464.3 ± 67.6 nm, and ZP was from −27.6 to −42.27 mV. The niosomal formulation was then loaded to aqueous polymer solution of 30% polyvinyl pyrrolidone (PVP) (MN-1), 30% PVP with 15% poly(vinyl alcohol) (PVA) (2:1) (MN-2), and 30% PVP with 15% PVA (1:1) (MN-3). The cumulative amount of ALS (Q) was in the following order: MN-1 > MN-2 > MN-3. All formulations in this study were stable at room temperature over two months, in terms of moisture content and drug content. In conclusion, a transdermal delivery of ALS niosomes combined in microneedles (MNs) was successfully prepared to provide sustained release of ALS.

Biofunctionalization of titanium surfaces with alendronate and albumin modulates osteoblast performance

BACKGROUND

Biofunctionalization of titanium surfaces can improve host responses, especially considering the time for osteointegration and patient recovery. This prompted us to modify titanium surfaces with alendronate and albumin and to investigate the behavior of osteoblasts on these surfaces.

METHODS

The biofunctionalization of titanium surfaces was characterized using classical physicochemical approaches and later used to challenge pre-osteoblast cells up to 24 h. Then their viability and molecular behavior were investigated using mitochondrial dehydrogenase activity and RTq-PCR technologies, respectively. Potential stimulus of extracellular remodeling was also investigated by zymography.

RESULTS

Our data indicates a differential behavior of cells responding to the surfaces, considering the activity of mitochondrial dehydrogenases. Molecularly, the differential expression of genes related with cell adhesion highlighted the importance of Integrin-β1, Fak, and Src. These 3 genes were significantly decreased in response to titanium surfaces modified with alendronate, but this behavior was reverted when alendronate was associated with albumin. Alendronate-modified surfaces promoted a significant increase on ECM remodeling, as well as culminating with greater gene activity related to the osteogenic phenotype (Runx2, Alp, Bsp).

CONCLUSION

Altogether, our study found interesting osteogenic behavior of cells in response to alendronate and albumin surfaces, which indicates the need for in vivo analyses to better consider these surfaces before clinical trials within the biomedical field.

Alendronate-Anionic Clay Nanohybrid for Enhanced Osteogenic Proliferation and Differentiation

BACKGROUND

Alendronate (AL), a drug for inhibiting osteoclast-mediated bone-resorption, was intercalated into an inorganic drug delivery nanovehicle, layered double hydroxide (LDH), to form a new nanohybrid, AL-LDH, with 1:1 heterostructure along the crystallographic C-axis. Based on the intercalation reaction strategy, the present AL-LDH drug delivery system (DDS) was realized with an enhanced drug efficacy of AL, which was confirmed by the improved proliferation and osteogenic differentiation of osteoblast-like cells (MG63).

METHODS

The AL-LDH nanohybrid was synthesized by conventional ion-exchange reaction and characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. Additionally, in vitro efficacy tests, such as cell proliferation and alkaline phosphatase (ALP) activity, were analyzed.

RESULTS

The AL was successfully intercalated into LDH via ion-exchange reaction, and thus prepared AL-LDH DDS was X-ray single phasic and chemically well defined. The accumulated AL content in MG63 cells treated with the AL-LDH DDS nanoparticles was determined to be 10.6-fold higher than that within those treated with the intact AL after incubation for 1 hour, suggesting that intercellular permeation of AL was facilitated thanks to the hybridization with drug delivery vehicle, LDH. Furthermore, both in vitro proliferation level and ALP activity of MG63 treated with the present hybrid drug, AL-LDH, were found to be much more enhanced than those treated with the intact AL. This is surely due to the fact that LDH could deliver AL drug very efficiently, although LDH itself does not show any effect on proliferation and osteogenic differentiation of MG63 cells.

CONCLUSION

The present AL-LDH could be considered as a promising DDS for improving efficacy of AL.

Synthesis and evaluation of alendronate-modified gelatin biopolymer as a novel osteotropic nanocarrier for gene therapy

AIM

To synthesize an osteotropic alendronate functionalized gelatin (ALN-gelatin) biopolymer for nanoparticle preparation and targeted delivery of DNA to osteoblasts for gene therapy applications.

MATERIALS & METHODS

Alendronate coupling to gelatin was confirmed using Fourier transform IR, (31)PNMR, x-ray diffraction (XRD) and differential scanning calorimetry. ALN-gelatin biopolymers prepared at various alendronate/gelatin ratios were utilized to prepare nanoparticles and were optimized in combination with DNA and gemini surfactant for transfecting both HEK-293 and MG-63 cell lines.

RESULTS

Gelatin functionalization was confirmed using the above methods. Uniform nanoparticles were obtained from a nanoprecipitation technique. ALN-gelatin/gemini/DNA complexes exhibited higher transfection efficiency in MG-63 osteosarcoma cell line compared with the positive control.

CONCLUSION

ALN-gelatin is a promising biopolymer for bone targeting of either small molecules or gene therapy applications.

Study on in vitro release and cell response to alendronate sodium-loaded ultrahigh molecular weight polyethylene loaded with alendronate sodium wear particles to treat the particles-induced osteolysis

The aim of this study is to investigate in vitro release and cell response to wear particles of ultrahigh molecular weight polyethylene loaded with alendronate sodium (UHMWPE-ALN), a potent bone resorption inhibitor. Wear particles of UHMWPE-ALN with different ALN contents (0.5 wt % or 1.0 wt %) and size ranges (<45 μm or 45-75 μm) were cocultured with macrophages (RAW264.7) and osteoblasts (MC3T3-E1), respectively. The in vitro ALN release was divided into three stages: an initial burst release, subsequent rapid release, and final slow release. The particle size and ALN content of UHMWPE-ALN wear particles affected the in vitro release mainly during initial burst and rapid release. Compared with the control cells, UHMWPE-ALN wear particles stimulated a significant elevation of tumor necrosis factor-alpha (TNF-α) release from macrophages but had no obvious effect on interleukin-6 release. However, this stimulation of TNF-α release could be reduced by ALN released from UHMWPE-ALN wear particles. The wear particle size had stronger effect of on the macrophages compared with the ALN concentration. After coculture with UHMWPE-ALN wear particles, osteoblast proliferation and alkaline phosphatase activities increased moderately with the increase in particle sizes and ALN concentrations. These results suggest that incorporation of ALN in UHMWPE-ALN may be an effective approach to prevent or reduce particles-induced osteolysis.