Preparation, evaluation, and first clinical use of177Lu-labeled hydroxyapatite (HA) particles in the treatment of rheumatoid arthritis: utility of cold kits for convenient dose formulation at hospital radiopharmacy

The Use of Microspheres for Cancer Embolization Therapy: Recent Advancements and Prospective

Embolization therapy involving biomaterials has improved the therapeutic strategy for most liver cancer treatments. Developing biomaterials as embolic agents has significantly improved patients' survival rates. Various embolic agents are present in liquid agents, foam, particulates, and particles. Some of the most applied embolic agents are microparticles, such as microspheres (3D micrometer-sized spherical particles). Microspheres with added functionalities are currently being developed for effective therapeutic embolization. Their excellent properties of high surface area and capacity for being loaded with radionuclides and alternate active or therapeutic agents provide an additional advantage to overcome limitations from traditional cancer treatments. Microspheres (non-radioactive and radioactive) have been widely used and explored for localized cancer treatment. Non-radioactive microspheres exhibit improved clinical performance as drug delivery vehicles in chemotherapy due to their controlled and sustained drug release to the target site. They offer better flow properties and are beneficial for the ease of delivery via injection procedures. In addition, radioactive microspheres have also been exploited for use as an embolic platform in internal radiotherapy as an alternative to cancer treatment. This short review summarizes the progressive development of non-radioactive and radioactive embolic microspheres, emphasizing material characteristics. The use of embolic microspheres for various modalities of therapeutic arterial embolization and their impact on therapeutic performance are also discussed.

A Novel Hydroxyapatite/Vitamin B12 Nanoformula for Treatment of Bone Damage: Preparation, Characterization, and Anti-Arthritic, Anti-Inflammatory, and Antioxidant Activities in Chemically Induced Arthritic Rats

The usage of nanomaterials for rheumatoid arthritis (RA) treatment can improve bioavailability and enable selective targeting. The current study prepares and evaluates the in vivo biological effects of a novel hydroxyapatite/vitamin B₁₂ nanoformula in Complete Freund's adjuvant-induced arthritis in rats. The synthesized nanoformula was characterized using XRD, FTIR, BET analysis, HERTEM, SEM, particle size, and zeta potential. We synthesized pure HAP NPs with 71.01% loading weight percentages of Vit B12 and 49 mg/g loading capacity. Loading of vitamin B₁₂ on hydroxyapatite was modeled by Monte Carlo simulation. Anti-arthritic, anti-inflammatory, and antioxidant effects of the prepared nanoformula were assessed. Treated arthritic rats showed lower levels of RF and CRP, IL-1β, TNF-α, IL-17, and ADAMTS-5, but higher IL-4 and TIMP-3 levels. In addition, the prepared nanoformula increased GSH content and GST antioxidant activity while decreasing LPO levels. Furthermore, it reduced the expression of TGF-β mRNA. Histopathological examinations revealed an improvement in joint injuries through the reduction of inflammatory cell infiltration, cartilage deterioration, and bone damage caused by Complete Freund's adjuvant. These findings indicate that the anti-arthritic, antioxidant, and anti-inflammatory properties of the prepared nanoformula could be useful for the development of new anti-arthritic treatments.

Nano-hydroxyapatite as a delivery system: overview and advancements

Nano-hydroxyapatite is being investigated as vital components of implants and dental and tissue engineering devices. It is found as a bone replacement due to its non-toxicity and cytocompatibility with dental tissues and bone. The reality that nanocrystalline hydroxyapatite can be made of porous granules and scaffolds. Additionally, it has a massive loading potential indicating its use as a transporter for drugs or a regulated drug release mechanism in pharmaceutical research. This review aims to present existing nano-hydroxyapatite research developments as a drug carrier employed in bone tissue disorders locally and deliver poorly soluble drugs with reduced bioavailability. We have discussed the nano-hydroxyapatite role in the delivery of drugs (i.e. anti-resorptive, anti-cancer, and antibiotics), proteins, genetic material, and radionuclides.

Hydroxyapatite and Titanium Dioxide Nanoparticles: Radiolabelling and In Vitro Stability of Prospective Theranostic Nanocarriers for 223Ra and 99mTc

Hydroxyapatite and titanium dioxide are widely used materials in a broad spectrum of branches. Due to their appropriate properties such as a large specific surface area, radiation stability or relatively low toxicity, they could be potentially used as nanocarriers for medicinal radionuclides for diagnostics and therapy. Two radiolabelling strategies of both nanomaterials were carried out by 99mTc for diagnostic purposes and by 223Ra for therapeutic purposes. The first one was the radionuclide sorption on ready-made nanoparticles and the second one was direct radionuclide incorporation into the structure of the nanoparticles. Achieved labelling yields were higher than 94% in all cases. Afterwards, in vitro stability tests were carried out in several solutions: physiological saline, bovine blood plasma, bovine blood serum, 1% and 5% human albumin solutions. In vitro stability studies were performed as short-term (59 h for 223Ra and 31 h for 99mTc) and long-term experiments (five half-lives of 223Ra, approx. 55 days). Both radiolabelled nanoparticles with 99mTc have shown similar released activities (about 20%) in all solutions. The best results were obtained for 223Ra radiolabelled titanium dioxide nanoparticles, where overall released activities were under 6% for 59 h study in all matrices and under 3% for 55 days in a long-term perspective.

Design and development of bioinspired calcium phosphate nanoparticles of MTX: pharmacodynamic and pharmacokinetic evaluation

The aim of this investigation is the management of rheumatoid arthritis (RA) by developing methotrexate-loaded calcium phosphate nanoparticles (MTX-CAP-NP) and to evaluate pharmacokinetic and pharmacodynamic behavior in adjuvant induced arthritis model. The nanoparticles were synthesized by wet precipitation method and optimized by Box-Behnken experimental design. MTX-CAP-NPs were characterized by TEM, FTIR, DSC and XRD studies. The particle size, zeta potential and entrapment efficiency of the optimized nanoparticles were found to be 204.90 ± 64 nm, -11.58 ± 4.80 mV, and 88.33 ± 3.74%, respectively. TEM, FTIR, DSC and XRD studies revealed that the developed nanoparticles were nearly spherical in shape and the crystalline structure of CAP-NP was not changed after MTX loading. The pharmacokinetic studies revealed that MTX-CAP-NP enhanced bioavailability of MTX by 2.6-fold when compared to marketed formulation (FOLITRAX-10). Under pharmacodynamic evaluation, arthritic assessment, radiography and histopathology studies revealed that CAP has ability to regenerate cartilage and bone therefore, together with MTX, MTX-CAP-NPs have shown significant reduction in disease progression. The overall work demonstrated that the developed nanodelivery system was well tolerated and more effective than the marketed formulation.

Barium titanate microparticles as potential carrier platform for lanthanide radionuclides for their use in the treatment of arthritis

Since the inception of radiation synovectomy, a host of radioactive colloids and microparticles incorporating suitable therapeutic radionuclides have been proposed for the treatment of arthritis. The present article reports the synthesis and evaluation of barium titanate microparticles as an innovative and effective carrier platform for lanthanide radionuclides in the preparation of therapeutic agents for treatment of arthritis. The material was synthesized by mechanochemical route and characterized by X-ray diffraction, scanning electron microscopy, surface area, and particle size distribution analyses. Loading of lanthanide radionuclides (¹⁶⁶ Ho, ¹⁵³ Sm, ¹⁷⁷ Lu, and ¹⁶⁹ Er) on the microparticles was achieved in high yield (> 95%) resulting in the formulation of loaded particulates with excellent radiochemical purities (> 99%). Radiolanthanide-loaded microparticles exhibited excellent in vitro stability in human serum. In vitro diethylene triamine pentaacetic acid challenge study indicated fairly strong chemical association of lanthanides with barium titanate microparticles. Long-term biodistribution studies carried out after administration of ¹⁷⁷ Lu-loaded microparticles into one of the knee joints of normal Wistar rats revealed near-complete retention of the formulation (> 96% of the administered radioactivity) within the joint cavity even 14 days post-administration. The excellent localization of the loaded microparticles was further confirmed by sequential whole-body radio-luminescence imaging studies carried out using ¹⁶⁶ Ho-loaded microparticles.

Hydroxyapatite (HA) microparticles labeled with (32)P - A promising option in the radiation synovectomy for inflamed joints

In the present article we describe a systematic approach pursued for the synthesis of (32)P-labeled hydroxyapatite (HA) microparticles (1-10µm size range) using no carrier added (NCA) (32)P produced in a nuclear reactor and animal evaluation of its utility as an expected viable radiopharmaceutical for the treatment of pain intensive arthrosis. NCA (32)P was produced via the (32)S(n,p)(32)P route in nuclear reactor with high radionuclidic purity (99.95±0.01%, n=5). Phosphorus-32-labeled hydroxyapatite microparticles (1-10µm size range) were synthesized with high radiochemical purity (99.0±0.3% n=12) under optimized conditions and the formulation showed excellent in vitro stability in saline as well as in rat serum. Intra-articular administration of the radiolabeled particles in the knee joints of normal Wistar rats showed near-complete retention of activity within the synovial cavity upto 1 month post-administration. The radiochemical formulation thus demonstrated promising features as a radiopharmaceutical for treatment of arthritis with excellent logistic advantage for shipment to sites distant from the production facility thanks to the suitable nuclear decay properties of (32)P.

Radiolanthanide-loaded agglomerated Fe3O4 nanoparticles for possible use in the treatment of arthritis: formulation, characterization and evaluation in rats

This investigation reports the preparation of agglomerated Fe₃O₄ nanoparticles and evaluation of its utility as a viable carrier in the preparation of radiolanthanides as potential therapeutic agents for the treatment of arthritis. The material was synthesized by a chemical route and characterized by XRD, FT-IR, SEM, EDX and TEM analysis. The surface of agglomerated particle possessed ion pairs (-O^-:Na⁺) after dispersing particles in a NaHCO₃ solution at pH = 7 which is conducive for radiolanthanide (*Ln = ⁹⁰Y, ¹⁵³Sm, ¹⁶⁶Ho, ¹⁶⁹Er, ¹⁷⁷Lu) loading by replacement of Na⁺ ions with tripositive radiolanthanide ions. Radiolanthanide-loaded particulates exhibited excellent in vitro stability up to ∼3 half-lives of the respective lanthanide radionuclides when stored in normal saline at 37 °C. The radiochemical purities of the loaded particulates were found to be retained to the extent of >70% after 48 h of storage when challenged by a strong chelator DTPA present at a concentration as high as 5 mM, indicating fairly strong chemical association of lanthanides with agglomerated Fe₃O₄ nanoparticles. Biodistribution studies of ⁹⁰Y and ¹⁶⁶Ho-loaded particulates carried out after intra-articular injection into one of the knee joints of a normal Wistar rat revealed near-complete retention of the radioactive preparations (>98% of the administered radioactivity) within the joint cavity even after 72 h post injection. This was further confirmed by sequential whole-body radio-luminescence imaging. These experimental results are indicative of the potential use of radiolanthanide-loaded agglomerated Fe₃O₄ nanoparticles for the treatment of arthritis.

Production of (177)Lu for Targeted Radionuclide Therapy: Available Options

BACKGROUND

This review provides a comprehensive summary of the production of (177)Lu to meet expected future research and clinical demands. Availability of options represents the cornerstone for sustainable growth for the routine production of adequate activity levels of (177)Lu having the required quality for preparation of a variety of (177)Lu-labeled radiopharmaceuticals. The tremendous prospects associated with production of (177)Lu for use in targeted radionuclide therapy (TRT) dictate that a holistic consideration should evaluate all governing factors that determine its success.

METHODS

While both "direct" and "indirect" reactor production routes offer the possibility for sustainable (177)Lu availability, there are several issues and challenges that must be considered to realize the full potential of these production strategies.

RESULTS

This article presents a mini review on the latest developments, current status, key challenges and possibilities for the near future.

CONCLUSION

A broad understanding and discussion of the issues associated with (177)Lu production and processing approaches would not only ensure sustained growth and future expansion for the availability and use of (177)Lu-labeled radiopharmaceuticals, but also help future developments.