Studies on liposome formulations for intra-articular delivery of clodronate

Synthesis of ionizable lipopolymers using split-Ugi reaction for pulmonary delivery of various size RNAs and gene editing

We present an efficient approach for synthesizing cationic poly(ethylene imine) derivatives using the multicomponent split-Ugi reaction to rapidly create a library of complex functional ionizable lipopolymers. We synthesized a diverse library of 155 polymers, formulated them into polyplexes to establish structure-activity relationships crucial for endosomal escape and efficient transfection. After discovering a lead structure, lipopolymer-lipid hybrid nanoparticles are introduced to preferentially deliver to and elicit effective mRNA transfection in lung endothelium and immune cells, including T cells with low in vivo toxicity. The lipopolymer-lipid hybrid nanoparticles showed 300-fold improvement in systemic mRNA delivery to the lung compared to in vivo -JetPEI ® . Lipopolymer-lipid hybrid nanoparticles demonstrated efficient delivery of mRNA-based therapeutics for treatment of two different disease models. Lewis Lung cancer progression was significantly delayed after treatment with loaded IL-12 mRNA in U155@lipids after repeated i.v. administration. Systemic delivery of human CFTR (hCFTR) mRNA resulted in production of functional form of CFTR protein in the lungs. The functionality of hCFTR protein was confirmed by restoration of CFTR- mediated chloride secretion in conductive airway epithelia in CFTR knockout mice after nasal instillation of hCFTR mRNA loaded U155@lipids. We further showed that, U155@lipids nanoparticles can deliver complex CRISPR-Cas9 based RNA cargo to the lung, achieving 5.6 ± 2.4 % gene editing in lung tissue. Moreover, we demonstrated successful PD-1 gene knockout of T cells in vivo . Our results highlight a versatile delivery platform for systemic delivering of mRNA of various sizes for gene therapy for a variety of therapeutics.

Impact of Tumor Barriers on Nanoparticle Delivery to Macrophages

The delivery of therapeutic nanoparticles to target cells is critical to their effectiveness. Here we quantified the impact of biological barriers on the delivery of nanoparticles to macrophages in two different tissues. We compared the delivery of gold nanoparticles to macrophages in the liver versus those in the tumor. We found that nanoparticle delivery to macrophages in the tumor was 75% less than to macrophages in the liver due to structural barriers. The tumor-associated macrophages took up more nanoparticles than Kupffer cells in the absence of barriers. Our results highlight the impact of biological barriers on nanoparticle delivery to cellular targets.

The Rationale for the Intra-Articular Administration of Clodronate in Osteoarthritis

BACKGROUND

Several pharmacological therapeutic approaches have been proposed to manage osteoarthritis (OA), including intra-articular (IA) injections. Although the discovery of clodronate, a bisphosphonate, dates back to the 1960s and the effects of its IA administration have been investigated for decades in animal models, mechanisms of action of this drug are not quite clear, particularly in OA. This scoping review is an overview of the biological as well as the clinical role of clodronic acid in OA.

METHOD

A scoping review based on the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model was performed to characterize the mechanisms of action of IA clodronate in OA and to evaluate its efficacy from a clinical point of view.

RESULTS

Several effects of clodronate have been observed in animal models of OA, including depletion of synovial lining cells that results in reduced production of chemokines (IL-1, TNF- α), growth factors (TGF-β, BMP 2/4), and metalloproteases (MMP 2/3/9); prevention of cartilage damage, synovial hyperplasia, and proteoglycans loss; reduction in joint inflammation, joint swelling, and osteophyte formation. From a clinical perspective, patients with knee OA treated with IA clodronate experienced improvements in pain and joint mobility.

CONCLUSION

Clodronate appears to have different mechanisms of action interfering with the pathogenic processes contributing to OA development and progression. This intervention demonstrated positive effects for patients affected by knee OA.

Liposome-encapsulated fish oil protein-tagged gold nanoparticles for intra-articular therapy in osteoarthritis

AIM

To provide multilayered combination therapies encompassing nanoparticles and organic peptides and to assess their efficacy in the treatment of arthritis.

MATERIALS & METHODS

Fish oil protein (FP) was isolated from fish oil glands and tagged with spherical gold nanoparticles (GNPs). Tagged GNPs were encapsulated in DPPC liposomes (FP-GNP-DPPC) and characterized.

RESULTS & CONCLUSION

FP increased the hydrophilicity of GNP, while encapsulation of FP-GNP within liposomes increased the hydrophobicity. In vitro release studies of FP-GNP-DPPC exhibited sustained release of FP in simulated synovial fluid. FP-GNP-DPPC injected into intra-articular joints of rats displayed anti-osteoarthritic effects in osteoarthritic rat model. This is the first study to report the anti-osteoarthritic activity of FP and DPPC encapsulated FP-GNP liposomes.

Chitosan-clodronate nanoparticles loaded in poloxamer gel for intra-articular administration

This work was based on the study of an intra-articular delivery system constituted by a poloxamer gel vehiculating clodronate in chitosan nanoparticles. This system has been conceived to obtain a specific and controlled release of clodronate in the joints to reduce the arthritis rheumatoid degenerative effect. Clodronate (CLO) is a first-generation bisphosphonate with anti-inflammatory properties, inhibiting the cytokine and NO secretion from macrophages, therefore causing apoptosis in these cells. This is related to its ability to be metabolized by cells and converted into a cytotoxic intermediate as a non-hydrolysable analogue of ATP. Chitosan (CHI) was used to develop nanosystems, by ionotropic gelation induced by clodronate itself. A fractional factorial experimental design allowed us to obtain nanoparticles, the diameter of which ranged from 200 to 300nm. Glutaraldehyde was used to increase nanoparticle stability and modify the drug release profile. The zeta potential value of crosslinked nanopaparticles was 21.0mV±1.3, while drug loading was 31.0%±5.4 w/w; nanoparticle yield was 18.2%±1.8 w/w, the encapsulation efficiency was 48.8%±9.9 w/w. Nanoparticles were homogenously loaded in a poloxamer sol, and the drug delivery system is produced in-situ after local administration, when sol become gel at physiological temperature. The properties of poloxamer gels containing CHI-CLO nanoparticles, such as viscosity, gelation temperature and drug release properties, were evaluated. In vitro studies were conducted to evaluate the effects of these nanoparticles on a human monocytic cell line (THP1). The results showed that this drug delivery system is more efficient, with respect to the free drug, to counteract the inflammatory process characteristic of several degenerative diseases.

Effect of particle size on the biodistribution of nano- and microparticles following intra-articular injection in mice

Intra-articular (IA) injection of extended drug release forms based on biodegradable microparticles holds promise for the treatment of joint diseases. However, the fate of microparticles following intra-articular injection is controversial and has not been thoroughly investigated. The aim of this work was therefore to evaluate the biodistribution of fluorescent poly(lactic acid) particles of different sizes after IA injection in arthritic or healthy mice. Regardless of the inflammatory status of the joint, 300 nm-nanoparticles leaked from the joint. Due to inflammation and related increase of vascular permeability, 3 μm-microparticles that were retained in the non-inflamed synovial membrane leaked from the inflamed joint. Complete retention of 10 μm-microparticles was observed independently of the joint inflammatory status. Embedding particles in a hyaluronic acid gel prolonged the retention of the formulations only in inflamed joints. Depending on particle's size, formulations were preferentially eliminated by blood vessels or lymphatic pathways. Poly(lactic acid) particles of 3 μm were biocompatible and retained in knee joints at least for 6 weeks. This work highlights the need to deliver hyaluronic acid-embedded particles of at least 3 μm to guarantee their retention in inflamed joints. These results will contribute to the rational design of long-lasting formulations to treat acute and chronic joint diseases.

Liposome technology for cardiovascular disease treatment and diagnosis

INTRODUCTION

Over the past several decades, liposomes have been used in a variety of applications, from delivery vehicles to cell membrane models. In terms of pharmaceutical use, they can offer control over the release of active agents encapsulated into their lipid bilayer or aqueous core, while providing protection from degradation in the body. In addition, liposomes are versatile carriers, because targeting moieties can be conjugated on the surface to enhance delivery efficiency. It is for these reasons that liposomes have been applied as carriers for a multitude of drugs and genetic material, and as contrast agents, aimed to treat and diagnose cardiovascular diseases.

AREAS COVERED

This review details advancements in liposome technology used in the field of cardiovascular medicine. In particular, the application of liposomes to cardiovascular disease treatment and diagnosis, with a focus on delivering drugs, genetic material and improving cardiovascular imaging, will be explored. Advances in targeting liposomes to the vasculature will also be detailed.

EXPERT OPINION

Liposomes may provide the means to deliver drugs and other pharmaceutical agents for cardiovascular applications; however, there is still a vast amount of research and clinical trials that must be performed before a formulation is brought to market. Advancements in targeting abilities within the body, as well as the introduction of theranostic liposomes, capable of both delivering treating and imaging cardiac diseases, may be expected in the future of this burgeoning field.

Micro- and Nano-Carrier Mediated Intra-Articular Drug Delivery Systems for the Treatment of Osteoarthritis

The objective of this paper is to provide readers with current developments of intra-articular drug delivery systems. In recent years, although the search for a clinically successful ideal carrier is ongoing, sustained-release systems, such as polymeric micro- and nanoparticles, liposomes, and hydrogels, are being extensively studied for intra-articular drug delivery purposes. The advantages associated with long-acting preparations include a longer effect of the drug in the action site and a reduced risk of infection due to numerous injections consequently. This paper discusses the recent developments in the field of intra-articular sustained-release delivery systems for the treatment of osteoarthritis.

Efficacy of chitosan microspheres for controlled intra-articular delivery of celecoxib in inflamed joints

The use of polymeric carriers in formulations of therapeutic drug delivery systems has gained widespread application, due to their advantage of being biodegradable and biocompatible. In this study, we aimed to prepare celecoxib-loaded chitosan microspheres for intra-articular administration and to compare the retention of the celecoxib solution and chitosan microspheres in the joint cavity. The microspheres were characterized for entrapment efficiency, particle size and surface morphology by scanning electron microscopy. In-vitro drug release studies of microspheres revealed that the microspheres are able to control the release of celecoxib over a period of 96 h. Biodistribution studies of celecoxib and chitosan microspheres were performed by radiolabelling with 99mTc and injecting intra-articularly in rats. The study indicated that following intra-articular administration the distribution of the drug to the organs, like liver and spleen, is very rapid compared with that of the microspheres. Compared with the drug solution, a 10-fold increase in the concentration of the drug in the joint was observed 24 h post intra-articular injection (P < 0.005) when drug was encapsulated in microspheres.

Interaction of cationic drugs with liposomes

Interactions between cationic drugs and anionic liposomes were studied by measuring binding of drugs and the effect of binding on liposome permeability. The measurements were analyzed in the context of a continuum model based on electrostatic interactions and a Langmuir isotherm. Experiments and modeling indicate that, although electrostatic interactions are important, the fraction of drug sequestered in the double-layer is negligible. The majority of drug enters the bilayer with the charged regions interacting with the charged lipid head groups and the lipophilic regions associated with the bilayer. The partitioning of the drug can be described by a Langmuir isotherm with the electrostatic interactions increasing the sublayer concentration of the drug. The binding isotherms are similar for all tricyclic antidepressants (TCA). Bupivacaine (BUP) binds significantly less compared to TCA because its structure is such that the charged region has minimal interactions with the lipid heads once the BUP molecule partitions inside the bilayer. Conversely, the TCAs are linear with distinct hydrophilic and lipophilic regions, allowing the lipophilic regions to lie inside the bilayer and the hydrophilic regions to protrude out. This conformation maximizes the permeability of the bilayer, leading to an increased release of a hydrophilic fluorescent dye from liposomes.

Intra-articular depot formulation principles: role in the management of postoperative pain and arthritic disorders

The joint cavity constitutes a discrete anatomical compartment that allows for local drug action after intra-articular injection. Drug delivery systems providing local prolonged drug action are warranted in the management of postoperative pain and not least arthritic disorders such as osteoarthritis. The present review surveys various themes related to the accomplishment of the correct timing of the events leading to optimal drug action in the joint space over a desired time period. This includes a brief account on (patho)physiological conditions and novel potential drug targets (and their location within the synovial space). Particular emphasis is paid to (i) the potential feasibility of various depot formulation principles for the intra-articular route of administration including their manufacture, drug release characteristics and in vivo fate, and (ii) how release, mass transfer and equilibrium processes may affect the intra-articular residence time and concentration of the active species at the ultimate receptor site.

Synergistic Effect of Phospholipid-Based Liposomes and Propylthiouracil on U-937 Cell Growth

Scientific evidence indicates that exogenous phospholipids in the form of liposomes can affect cell growth. Effects of liposomes on cell growth depend on several factors including composition of liposomes, lipid concentration, and type of cells studied. Because phagocytic cells such as monocytes and macrophages are natural targets of liposomes, intracellular delivery of drugs to modulate cellular activity of these cells is of interest. We explored the effects of phospholipid-based liposomes composed of soy bean phosphatidylcholine (PC) as the main lipid component on U-937 cell growth. Effects of charge-imposing lipids and cholesterol were also studied. In addition, we investigated whether phospholipid-based liposomes would exert any interaction on cell growth with propylthiouracil, a drug with known antiproliferative activity. We found that PC in the form of extruded liposomes had intrinsic antiproliferative activity on U-937 cells at concentrations of 200 microM and up without any appreciable cytotoxicity. Phosphatidylserine and phosphatidylglycerol, but not dicetlylphosphate, at 10 mol% increased growth retardation activity of PC liposomes. Cholesterol at 30 mol% did not have any effect on cell growth, except for liposomes composed of PC and phosphatidylserine, where growth retardation was negated in the presence of cholesterol. Synergistic effect on cell growth was seen with certain liposome compositions when 5.5 microg/mL of propylthiouracil was coincubated. The results of this study suggest that the effects of exogenous lipids on cell growth should be taken into consideration when PC-based liposomes are to be used as drug delivery systems, especially when the targets are cells with phagocytic activity.

Preparation of alendronate liposomes for enhanced stability and bioactivity: in vitro and in vivo characterization

Liposomes containing bisphosphonates have been shown to deplete circulating monocytes and reduce experimental restenosis. However, acceptable shelf life was not achieved, and the disruption extent and rate of the vesicles in the circulation has not been examined. Designing an optimal liposomal formulation in general, and for an anti-inflammatory effect in particular, requires careful consideration of the factors that contribute to their in vitro stability and integrity in the blood after injection. An improved liposomal alendronate formulation was prepared by a modified thin lipid film hydration technique followed by extrusion, resulting in relatively smaller size vesicles, narrow size distribution, and low drug to lipid ratio in comparison to the reverse phase evaporation method. In order to rule out premature leakage of the drug, the integrity of the vesicles was examined by means of size-exclusion chromatography in vitro and in vivo, with subsequent analysis of size, drug (fractions of encapsulated and free) and lipid concentrations. Vesicles were found to be stable in serum, with 15 +/- 3% leakage of the drug after 10 min in rabbit's circulation, and intact liposomes were detected in the circulation 24 h following administration. It is concluded that the new formulation results in increased stability (2.5 years) as determined by the insignificant changes in vesicle size, drug leakage, lipid and drug stability, in vitro bioactivity (macrophages inhibition), as well as in vivo in depleting circulating monocytes and inhibition of restenosis in rabbits. Our in vitro stability results regarding dilution in serum paralleled in vivo data. Thus, in vitro assessment may provide a valuable tool in assessing in vivo integrity of liposomal formulations.

The potential of liposomal drug delivery for the treatment of inflammatory arthritis

OBJECTIVE

To review the use of liposomes as a delivery agent in inflammatory arthritis.

METHODS

The literature on liposomes and liposomal drug delivery for the treatment of inflammatory arthritis was reviewed. A PubMed search of articles in the English-language journals from 1965 to 2007 was performed. The index words used were as follows: "rheumatoid arthritis," "liposomes," and "targeted delivery." Papers identified were reviewed, abstracted, and summarized.

RESULTS

Liposomes have the capacity to be used as delivery and targeting agents for the administration of antirheumatic drugs at lower doses with reduced toxicity. In other areas of medicine, the pace of progress has been rapid. In the case of infectious diseases and cancer, liposomal drug delivery has progressed and developed into commercially viable therapeutic options for the treatment of fungal infections (amphotericin B), or metastatic breast cancer and Kaposi sarcoma (doxorubicin, daunorubicin), respectively. In arthritis, the efficacy of prednisolone-loaded long-circulating liposomes is currently being evaluated in a phase II clinical trial. Liposome's application to arthritis is still in its infancy but appears promising as new patents are filed. With improvements in liposomal formulation and targeted synovial delivery, liposomes offer increased therapeutic activity and improvement in the risk-benefit ratio.

CONCLUSION

Recent research into synovial targets and improved liposomal formulations continues to improve our capacity to use liposomes for targeted delivery. With time, this approach has the potential to improve drug delivery and reduce systemic complications.

Celecoxib incorporated chitosan microspheres: in vitro and in vivo evaluation

Recently, considerable interest has been focussed on the use of biodegradable polymers for specialized applications such as controlled release of drug formulations; meanwhile, microsphere drug delivery systems using various kinds of biodegradable polymers have been studied extensively during the past two decades. In the present investigation, it was aimed to prepare microsphere formulations of celecoxib using a natural polymer, chitosan as a carrier for intra-articular administration to extend the retention of the drug in the knee joint. Microsphere formulations were evaluated in vitro for particle size, entrapment efficiency, surface morphology and in vitro drug release. For in vivo studies, (99m)Technetium- labeled glutathione was used as a radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. Evaluation of arthritic lesions post therapy in rats showed a significant difference (P < 0.005) in the group treated with celecoxib solution compared to the group treated with celecoxib loaded chitosan microspheres.

The molecular mechanism of action of the antiresorptive and antiinflammatory drug clodronate: evidence for the formation in vivo of a metabolite that inhibits bone resorption and causes osteoclast and macrophage apoptosis

OBJECTIVE

The primary aims of this study were to determine whether clodronate and liposome-encapsulated clodronate are metabolized to adenosine 5'-(beta,gamma-dichloromethylene) triphosphate (AppCCl2p) by osteoclasts and macrophages in vivo, and to determine whether intracellular accumulation of this metabolite accounts for the antiresorptive and antimacrophage effects of clodronate. To compare the mechanism of action of clodronate and alendronate, effects on protein prenylation in osteoclasts and macrophages in vivo were also assessed.

METHODS

High-performance liquid chroma-tography-mass spectrometry was used to determine whether rabbit osteoclasts (purified ex vivo with immunomagnetic beads) metabolize clodronate, and whether rat peritoneal macrophages metabolize liposome-encapsulated clodronate, following in vivo administration. The effects of clodronate and AppCCl2p on bone resorption, osteoclast number, and apoptosis in vitro were compared. Using an antibody to the unprenylated form of RaplA, effects on protein prenylation were assessed by Western blot analysis of osteoclast and peritoneal macrophage lysates from bisphosphonate-treated animals.

RESULTS

AppCCl2p could be detected in extracts from osteoclasts purified from clodronate-treated rabbits. Intracellular accumulation of AppCCl2p caused a reduction in the number of osteoclasts, increased osteoclast apoptosis, and inhibited bone resorption in vitro. These effects were indistinguishable from those of clodronate. Liposome-encapsulated clodronate was also metabolized to AppCCl2p by rat peritoneal macrophages in vivo. Liposome-encapsulated clodronate caused an increase in peritoneal macrophage apoptosis in ex vivo cultures that was indistinguishable from the increase in apoptosis caused by liposome-encapsulated AppCCl2p. Unlike alendronate, clodronate and its metabolite did not affect prenylation of the small GTPase RaplA in osteoclasts or macrophages in vivo.

CONCLUSION

These results provide the first direct evidence that the antiinflammatory and antiresorptive effects of clodronate on macrophages and osteoclasts in vivo occur via the intracellular formation of AppCCl2p.

Effects of low-dose, noncytotoxic, intraarticular liposomal clodronate on development of erosions and proteoglycan loss in established antigen-induced arthritis in rabbits

OBJECTIVE

To assess the clinical and histologic effects of an intraarticular application of low-dose (non-cytotoxic) liposomal clodronate in established antigen-induced monarthritis (AIA) in rabbits.

METHODS

AIA was monitored by assessments of joint swelling, C-reactive protein levels, and radiographic changes in 17 NZW rabbits for 8 weeks during the course of weekly intraarticular injections of liposomal clodronate (0.145 mg/injection, low dose) or "empty" liposomes. The contralateral knee was injected with liposome buffer alone as the control. End-point analyses included macroscopic joint examination, immuno- and TUNEL staining, Safranin O staining/microspectrophotometry, and tumor necrosis factor alpha (TNFalpha) convertase enzyme (TACE) inhibition assay.

RESULTS

Liposomal clodronate-treated rabbits showed a reduction and delay in joint swelling during the first 3 injections. Expression of matrix-bound (solubilized) TNFalpha, lining cell hyperplasia, and levels of RAM-11+ macrophages were low in the synovium of the liposomal clodronate treatment group, but the proportion of apoptotic lining cells was not affected. The radiologic score was low at the end of weeks 2 and 4, but at 8 weeks, no difference, compared with controls, was found in pannus formation or in the extent of joint erosion; also, joint swelling was higher than before initiation of treatment. Injections of liposomal clodronate prevented cartilage proteoglycan loss, which was significant in the superficial zone only. TACE activity was not inhibited by clodronate.

CONCLUSION

Liposomal clodronate had temporary antiinflammatory and antierosive effects on established AIA in rabbits. Over the long-term, the loss of cartilage proteoglycans was halted. This observed treatment effect may be related to the inhibition of TNFalpha production and processing in the synovium.

Rapid Screening Method for Osteoclast Differentiation in Vitro That Measures Tartrate-resistant Acid Phosphatase 5b Activity Secreted into the Culture Medium

Background: Osteoclasts secrete tartrate-resistant acid phosphatase (TRAP; EC 3.1.3.2) 5b into the circulation. We studied the release of TRAP 5b from osteoclasts using a mouse in vitro osteoclast differentiation assay.

Methods: We developed and characterized a polyclonal antiserum in rabbits, using purified human osteoclastic TRAP 5b as antigen. The antiserum was specific for TRAP in Western analysis of mouse osteoclast culture medium and was used to develop an immunoassay. We cultured mouse bone marrow-derived osteoclast precursor cells for 3–7 days with or without clodronate in the presence of vitamin D and analyzed the number of osteoclasts formed and the amount of TRAP 5b activity released into the culture medium.

Results: TRAP 5b activity was not secreted from osteoclast precursor cells. Addition of clodronate-containing liposomes decreased in a dose-dependent manner the number of osteoclasts and TRAP 5b activity released in 6-day cultures. The amount of TRAP 5b activity in the medium detected by the immunoassay correlated significantly with the number of osteoclasts formed (r = 0.94; P &lt;0.0001; n = 120).

Conclusions: The TRAP 5b immunoassay can be used to replace the laborious and time-consuming microscopic counting of osteoclasts in the osteoclast differentiation assay and to test the effects of potential therapeutic agents on osteoclast differentiation, enabling fast screening of large amounts of potential therapeutic agents.

Toxicity of gamma irradiated liposomes. 2. In vitro effects on cells in culture

In this study, the effects of liposome composition and gamma irradiation on their interactions with cell cultures were studied. The cytotoxicity test and the growth inhibition test clearly revealed toxic effects of liposomes composed of unsaturated phospholipids and gamma irradiation of these preparations enhanced their toxic effects. The murine fibroblast cell-line L 929 was less affected compared to the macrophage cell-line RAW 264 with a higher endocytic capacity. On the other hand, both gamma irradiated and non-irradiated liposomes composed of saturated phospholipids were non-toxic for the cells and irradiation did not affect their drug delivery properties. Hence, it seems that gamma irradiation is appropriate for sterilisation of these liposomes.

Characterization of ciprofloxacin liposomes: derivative ultraviolet spectrophotometric determinations

Neutral, (-) and (+) charged CF encapusulated liposome formulations prepared with EPC:Chol and DPPC:Chol lipids were investigated for their loading capacity, encapsulation % and release properties. CF amounts in the liposomes were estimated using derivative UV spectroscopy. Among the liposome formulations DPPC:Chol and EPC:Chol neutral formulations had a significantly higher loading capacity and slowest release rate compared with (-) and (+) charged liposomes. The derivative UV spectroscopy was found to be an easy and sensitive method for direct estimation of CF in liposomes.