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

Intra-articular targeting of nanomaterials for the treatment of osteoarthritis

Osteoarthritis is a prevalent and debilitating disease that involves pathological contributions from numerous joint tissues and cells. The joint is a challenging arena for drug delivery, since the joint has poor bioavailability for systemically administered drugs and experiences rapid clearance of therapeutics after intra-articular injection. Moreover, each tissue within the joint presents unique barriers to drug localization. In this review, the various applications of nanotechnology to overcome these drug delivery limitations are investigated. Nanomaterials have reliably shown improvements to retention profiles of drugs within the joint space relative to injected free drugs. Additionally, nanomaterials have been modified through active and passive targeting strategies to facilitate interactions with and localization within specific joint tissues such as cartilage and synovium. Last, the limitations of drawing cross-study comparisons, the implications of synovial fluid, and the potential importance of multi-modal therapeutic strategies are discussed. As emerging, cell-specific disease modifying osteoarthritis drugs continue to be developed, the need for targeted nanomaterial delivery will likely become critical for effective clinical translation of therapeutics for osteoarthritis. STATEMENT OF SIGNIFICANCE: Improving drug delivery to the joint is a pressing clinical need. Over 27 million Americans live with osteoarthritis, and this figure is continuously expanding. Numerous drugs have been investigated but have failed in clinical trials, likely related to poor bioavailability to target cells. This article comprehensively reviews the advances in nano-scale delivery vehicles designed to overcome the delivery barriers in the joint. This is the first review to analyze active and passive targeting strategies systematically for different target sites while also delineating between tissue homing and whole joint retention. By bringing together the lessons learned across numerous nano-scale platforms, researchers may be able to hone future nanomaterial designs, allowing emerging therapeutics to perform with clinically relevant efficacy and disease modifying potential.

Injectable biomaterials for delivery of interleukin-1 receptor antagonist: Toward improving its therapeutic effect

Interleukin-1 receptor antagonist (IL-1Ra) is a naturally occurring anti-inflammatory cytokine that inhibits IL-1 activity and has been proposed to treat a wide variety of systemic and local inflammatory pathologies for multiple decades. However, the short half-life and high concentration required to inhibit IL-1 activity has limited its use in clinical applications. Many strategies have been developed with the goal of improving the therapeutic efficacy of IL-1Ra for a variety of pathologies, including fusing IL-1Ra to protein/peptide/polymer partners, releasing IL-1Ra from injectable polymer or mineral particles, and release of IL-1Ra from injectable coacervates and gels. This literature review examines injectable biomaterials engineered to improve IL-1Ra delivery, both locally and systemically, to increase its efficacy and ease of use in clinic. STATEMENT OF SIGNIFICANCE: Interleukin-1 receptor antagonist (IL-1Ra) is a therapeutic protein with the potential to treat numerous inflammatory conditions and diseases. However, its short biological half-life and high therapeutic concentration may limit its utility in all but a few clinical scenarios. In this review, we present the biomaterial based delivery strategies which have been explored to deliver IL-1Ra to improve its efficacy and applicability to treat inflammation.

Bioactive factors for cartilage repair and regeneration: Improving delivery, retention, and activity

Articular cartilage is a remarkable tissue whose sophisticated composition and architecture allow it to withstand complex stresses within the joint. Once injured, cartilage lacks the capacity to self-repair, and injuries often progress to joint wide osteoarthritis (OA) resulting in debilitating pain and loss of mobility. Current palliative and surgical management provides short-term symptom relief, but almost always progresses to further deterioration in the long term. A number of bioactive factors, including drugs, corticosteroids, and growth factors, have been utilized in the clinic, in clinical trials, or in emerging research studies to alleviate the inflamed joint environment or to promote new cartilage tissue formation. However, these therapies remain limited in their duration and effectiveness. For this reason, current efforts are focused on improving the localization, retention, and activity of these bioactive factors. The purpose of this review is to highlight recent advances in drug delivery for the treatment of damaged or degenerated cartilage. First, we summarize material and modification techniques to improve the delivery of these factors to damaged tissue and enhance their retention and action within the joint environment. Second, we discuss recent studies using novel methods to promote new cartilage formation via biofactor delivery, that have potential for improving future long-term clinical outcomes. Lastly, we review the emerging field of orthobiologics, using delivered and endogenous cells as drug-delivering "factories" to preserve and restore joint health. Enhancing drug delivery systems can improve both restorative and regenerative treatments for damaged cartilage. STATEMENT OF SIGNIFICANCE: Articular cartilage is a remarkable and sophisticated tissue that tolerates complex stresses within the joint. When injured, cartilage cannot self-repair, and these injuries often progress to joint-wide osteoarthritis, causing patients debilitating pain and loss of mobility. Current palliative and surgical treatments only provide short-term symptomatic relief and are limited with regards to efficiency and efficacy. Bioactive factors, such as drugs and growth factors, can improve outcomes to either stabilize the degenerated environment or regenerate replacement tissue. This review highlights recent advances and novel techniques to enhance the delivery, localization, retention, and activity of these factors, providing an overview of the cartilage drug delivery field that can guide future research in restorative and regenerative treatments for damaged cartilage.

Cartilage penetrating cationic peptide carriers for applications in drug delivery to avascular negatively charged tissues

Drug delivery to avascular, negatively charged tissues like cartilage remains a challenge. The constant turnover of synovial fluid results in short residence time of administered drugs in the joint space and the dense negatively charged matrix of cartilage hinders their diffusive transport. Drugs are, therefore, unable to reach their cell and matrix targets in sufficient doses, and fail to elicit relevant biological response, which has led to unsuccessful clinical trials. The high negative fixed charge density (FCD) of cartilage, however, can be used to convert cartilage from a barrier to drug entry into a depot by making drugs positively charged. Here we design cartilage penetrating and binding cationic peptide carriers (CPCs) with varying net charge, spatial distribution and hydrophobicity to deliver large-sized therapeutics and investigate their electro-diffusive transport in healthy and arthritic cartilage. We showed that CPC uptake increased with increasing net charge up to +14 but dropped as charge increased further due to stronger binding interactions that hindered CPC penetrability and uptake showing that weak-reversible binding is key to enable their penetration through full tissue thickness. Even after 90% GAG depletion, while CPC +14 uptake reduced by over 50% but still had a significantly high value of 148× showing that intra-tissue long-range charge-based binding is further stabilized by short-range H-bond and hydrophobic interactions. The work presents an approach for rational design of cationic carriers based on tissue FCD and properties of macromolecules to be delivered. These design rules can be extended to drug delivery for other avascular, negatively charged tissues. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) remains an untreatable disease partly due to short joint residence time of drugs and a lack of delivery methods that can effectively target the dense, avascular, highly negatively charged cartilage tissue. In this study, we designed cartilage penetrating and binding cationic peptide carriers (CPCs) that, due to their optimal charge provide adequate electrical driving force to rapidly transport OA drugs into cartilage and reach their cell and matrix targets in therapeutic doses before drugs exit the joint space. This way cartilage is converted from being a barrier to drug entry into a drug depot that can provide sustained drug release for several weeks. This study also investigates synergistic effects of short-range H-bond and hydrophobic interactions in combination with long-range electrostatic interactions on intra-cartilage solute transport. The work provides rules for rational design of cartilage penetrating charge-based carriers depending on the net charge of tissue (normal versus arthritic), macromolecule to be delivered and whether the application is in drug delivery or tissue imaging.

The effects of intra-articular injection of ibuprofen on knee joint cartilage and synovium in rats

OBJECTIVE

The aim of this animal study was to investigate the short and long-term local histomorphologic effects and the utility of intra-articular application of ibuprofen.

METHODS

Forty-six Wistar Albino rats were used in the study. The rats were randomized into 5 groups of 8 and a sham group of 6. The 40 rats in the study groups were anaesthetised with 60 mg/kg of ketamine, then 0.25 ml ibuprofen (25 mg) was injected to the right knee joint of each rat (ibuprofen group) and 0.25 ml 0.9% saline to the left knee joint as the control group. To the 6 rats in the sham group, only puncture was applied to both knee joints. The rats in each of the 5 study groups were sacrificed on days 1, 2, 7, 14 and 21 respectively. The histomorphologic changes were graded on a 6-point scale regarding inflammation of the synovia, cartilage tissue, and subchondral bone. Inflammation scores were compared using the Mann Whitney U-test and comparisons of the sacrifice day and drug used were evaluated with the Kruskal Wallis test. The p values below 0.05 were considered as significant.

RESULTS

Statistically significant difference was found between the ibuprofen injected knees (10/40) and the saline injected (0/40) and sham knees (0/12) in respect of hematoma positivity (p = 0.002). Significantly higher inflammation scores were found in ibuprofen injected knees on the 1st, 2nd, 7th and 14th days compared to controls and sham (p < 0.05). Inflammation scores were similar in ibuprofen injected knees with and without hematoma (p > 0.05). Inflammation of the ibuprofen injected group was most severe on day one and the severity of inflammation reduced gradually throughout the 3 weeks.

CONCLUSION

Our results show that intra-articular injection of ibuprofen can cause intra-articular hematoma. It also leads to transient inflammation of the synovia that is more severe in the early period, which gradually recovers.

Human disorders associated with inflammation and the evolving role of natural products to overcome

Inflammation is a biological function which triggered after the mechanical tissue disruption or from the responses by the incidence of physical, chemical or biological negotiator in body. These responses are essential act provided by the immune system during infection and tissue injury to maintain normal tissue homeostasis. Inflammation is a quite complicated process at molecular level with the involvement of several proinflammatory expressions. Several health problems are associated with prolonged inflammation, which effects nearly all major to minor diseases. The molecular and epidemiological studies jagged that the inflammation is closely associated with several disorders with their specific targets. It would be great achievement for human health around the world to overcome on inflammation. Mostly used anti-inflammatory drugs are at high risk of side effects and also expensive. Hence, the plant-based formulations gained a wide acceptance by the public and medical experts to treat it. Due to extensive dispersal, chemical diversity and systematically established biological potentials of natural products have induced renewed awareness as a gifted source for medications. However, today's urgent need to search for cheaper, more potent and safe anti-inflammatory medications to overcome on current situation. The goal of this review to compile an update on inflammation, associated diseases, molecular targets, inflammatory mediators and role of natural products. The entire text concise the involvement of various cytokines in pathogenesis of various human disorders. This assignment discussed about 321 natural products with their promising anti-inflammatory potential discovered during January 2009 to December 2018 with 262 citations.

Mechanically-Activated Microcapsules for 'On-Demand' Drug Delivery in Dynamically Loaded Musculoskeletal Tissues

Delivery of biofactors in a precise and controlled fashion remains a clinical challenge. Stimuli-responsive delivery systems can facilitate 'on-demand' release of therapeutics in response to a variety of physiologic triggering mechanisms (e.g. pH, temperature). However, few systems to date have taken advantage of mechanical inputs from the microenvironment to initiate drug release. Here, we developed mechanically-activated microcapsules (MAMCs) that are designed to deliver therapeutics in an on-demand fashion in response to the mechanically loaded environment of regenerating musculoskeletal tissues, with the ultimate goal of furthering tissue repair. To establish a suite of microcapsules with different thresholds for mechano-activation, we first manipulated MAMC physical dimensions and composition, and evaluated their mechano-response under both direct 2D compression and in 3D matrices mimicking the extracellular matrix properties and dynamic loading environment of regenerating tissue. To demonstrate the feasibility of this delivery system, we used an engineered cartilage model to test the efficacy of mechanically-instigated release of TGF-β3 on the chondrogenesis of mesenchymal stem cells. These data establish a novel platform by which to tune the release of therapeutics and/or regenerative factors based on the physiologic dynamic mechanical loading environment, and will find widespread application in the repair and regeneration of numerous musculoskeletal tissues.

Hyperosmolar Potassium (K+) Treatment Suppresses Osteoarthritic Chondrocyte Catabolic and Inflammatory Protein Production in a 3-Dimensional In Vitro Model

OBJECTIVE

The main goal of this study was to provide a proof-of-concept demonstrating that hyperosmolar K⁺ solutions can limit production of catabolic and inflammatory mediators in human osteoarthritic chondrocytes (OACs).

METHODS

A 3-dimensional in vitro model with poly(ethylene glycol) diacrylate (PEGDA) hydrogels was used. Catabolic and pro-inflammatory protein production from encapsulated OACs was assessed following culture for 1 or 7 days in the presence or absence of 80 mM K⁺ gluconate, 80 mM sodium (Na⁺) gluconate, or 160 mM sucrose, each added to culture media (final osmolarity ~490 mOsm).

RESULTS

Relative to untreated controls, OACs treated with hyperosmolar (80 mM Na⁺ gluconate or 160 mM sucrose) solutions produced lower levels of catabolic and inflammatory mediators in a marker- and time-dependent manner (i.e., MMP-9 after 1 day; MCP-1 after 7 days ( P ≤ 0.015)). In contrast, OAC treatment with 80 mM K⁺ gluconate reduced catabolic and inflammatory mediators to a greater extent (both the number of markers and degree of suppression) relative to untreated, Na⁺ gluconate, or sucrose controls (i.e., MMP-3, -9, -13, TIMP-1, MCP-1, and IL-8 after 1 day; MMP-1, -3, -9, -13, TIMP-1, MCP-1, and IL-8 after 7 days ( P ≤ 0.029).

CONCLUSIONS

Hyperosmolar K⁺ solutions are capable of attenuating protein production of catabolic and inflammatory OA markers, providing the proof-of-concept needed for further development of a K⁺-based intra-articular injection for OA treatment. Moreover, K⁺ performed significantly better than Na⁺- or sucrose-based solutions, supporting the application of K⁺ toward improving irrigation solutions for joint surgery.

Intra-articular treatment options for knee osteoarthritis

Intra-articular drug delivery has a number of advantages over systemic administration; however, for the past 20 years, intra-articular treatment options for the management of knee osteoarthritis (OA) have been limited to analgesics, glucocorticoids, hyaluronic acid (HA) and a small number of unproven alternative therapies. Although HA and glucocorticoids can provide clinically meaningful benefits to an appreciable number of patients, emerging evidence indicates that the apparent effectiveness of these treatments is largely a result of other factors, including the placebo effect. Biologic drugs that target inflammatory processes are used to manage rheumatoid arthritis, but have not translated well into use in OA. A lack of high-level evidence and methodological limitations hinder our understanding of so-called 'stem' cell therapies and, although the off-label administration of intra-articular cell therapies (such as platelet-rich plasma and bone marrow aspirate concentrate) is common, high-quality clinical data are needed before these treatments can be recommended. A number of promising intra-articular treatments are currently in clinical development in the United States, including small-molecule and biologic therapies, devices and gene therapies. Although the prospect of new, non-surgical treatments for OA is exciting, the benefits of new treatments must be carefully weighed against their costs and potential risks.

Suppression of cathepsin K biomarker in synovial fluid as a free-drug-driven process

Cathepsin K (CatK) inhibitors exhibited chondroprotective and pain-reducing effects in animal models, however, improvements were relatively modest at dose levels achieving maximal suppression of CatK biomarkers in urine. In this report, a previously characterized CatK inhibitor (MK-1256) is utilized to explore the potential of reduced target engagement and/or suboptimal exposure (free drug) as limiting factors to the pharmacological potential of CatK inhibitors in the knee joint. Following oral administration of MK-1256 at a dose level achieving maximal inhibition of urinary biomarker (helical peptide) in dogs, full suppression of the biomarker in synovial fluid was observed. Subsequent tissue distribution studies conducted in dogs and rabbits revealed that MK-1256 levels in synovial fluid and cartilage were consistent with the free-drug hypothesis. Reasonable projection (within twofold) of drug levels in these tissues can be made based on plasma drug concentration with adjustments for binding factors. These results indicate that the previously observed efficacies in the animal models were not limited by compound distribution or target engagement in the knee tissues.

Green fluorescent proteins engineered for cartilage-targeted drug delivery: Insights for transport into highly charged avascular tissues

Osteoarthritis (OA), the most common form of arthritis, is a multi-factorial disease that primarily affects cartilage as well as other joint tissues such as subchondral bone. The lack of effective drug delivery, due to the avascular nature of cartilage and the rapid clearance of intra-articularly delivered drugs via the synovium, remains a major challenge in the development of disease modifying drugs for OA. Cationic delivery carriers can significantly enhance the uptake, penetration and retention of drugs in cartilage by interacting with negatively charged matrix proteoglycans. In this study, we used "supercharged" green fluorescent proteins (GFPs), engineered to have a wide range of net positive charge and surface charge distributions, to characterize the effects of carrier charge on transport into cartilage in isolation of other factors such as carrier size and shape. We quantified the uptake, extent of cartilage penetration and cellular uptake of the GFP variants into living human knee cartilage and bovine cartilage explants. Based on these results, we identified optimal net charges of GFP carriers for potential drug targets located within cartilage extracellular matrix as well as the resident live chondrocytes. These cationic GFPs did not have adverse effects on cartilage in terms of measured cell viability and metabolism, cartilage cell biosynthesis and matrix degradation at doses needed for drug delivery. In addition to quantifying the kinetics of GFP uptake, we developed a predictive mathematical model for transport of the GFP variants that exhibited the highest uptake and penetration into cartilage. This model was further used to predict the transport behavior of GFPs during scale-up to in vivo applications such as intra-articular injection into human knees. The insights gained from this study set the stage for development of cartilage-targeted delivery systems to prevent cartilage degeneration, improve tissue regeneration and reduce inflammation that may cause degradation of other joint tissues affected by OA.

Controlled release of celecoxib inhibits inflammation, bone cysts and osteophyte formation in a preclinical model of osteoarthritis

Major hallmarks of osteoarthritis (OA) are cartilage degeneration, inflammation and osteophyte formation. COX-2 inhibitors counteract inflammation-related pain, but their prolonged oral use entails the risk for side effects. Local and prolonged administration in biocompatible and degradable drug delivery biomaterials could offer an efficient and safe treatment for the long-term management of OA symptoms. Therefore, we evaluated the disease-modifying effects and the optimal dose of polyesteramide microspheres delivering the COX-2 inhibitor celecoxib in a rat OA model. Four weeks after OA induction by anterior cruciate ligament transection and partial medial meniscectomy, 8-week-old female rats (n = 6/group) were injected intra-articular with celecoxib-loaded microspheres at three dosages (0.03, 0.23 or 0.39 mg). Unloaded microspheres served as control. During the 16-week follow-up, static weight bearing and plasma celecoxib concentrations were monitored. Post-mortem, micro-computed tomography and knee joint histology determined progression of synovitis, osteophyte formation, subchondral bone changes, and cartilage integrity. Systemic celecoxib levels were below the detection limit 6 days upon delivery. Systemic and local adverse effects were absent. Local delivery of celecoxib reduced the formation of osteophytes, subchondral sclerosis, bone cysts and calcified loose bodies, and reduced synovial inflammation, while cartilage histology was unaffected. Even though the effects on pain could not be evualated directly in the current model, our results suggest the application of celecoxib-loaded microspheres holds promise as novel, safe and effective treatment for inflammation and pain in OA.

Drug-fortified liposomes as carriers for sustained release of NSAIDs: The concept and its validation in the animal model for the treatment of arthritis

Drug-fortified cationic liposomes of 6‑methoxy‑2‑naphthylacetic acid (6‑MNA) were prepared and characterized by various techniques. The residence time of drug-fortified liposomes in joint cavity was evaluated by intra-articular (IA) administration of the radio-labeled (^99mTc) liposomal formulation in the inflamed joints in rats. The cationic liposomal formulation composed of 6‑MNA (3) as an active agent, its double salt (4) with the lipid 1,2‑distearoyl‑sn‑glycero‑3‑phosphoethanolamine (DSPE), and pharmaceutically acceptable excipients such as hydrogenated soyabean phospatidylcholine (HSPC) and 1,2‑dioleyloxy‑3‑trimethylammoniumpropane chloride (DOTAP) were developed using thin film hydration technique. The cryo-TEM analysis confirmed that the prepared optimized liposomal formulation (DFL-2) was a mixture of small unilamellar vesicles (SUVs), large unilamellar vesicles (LUVs) and multilamellar vesicles (MLVs). In addition, the TEM analysis confirmed that the prepared liposomes were of spherical in shape having liposome size in the range of 500-900 nm and zeta potential of about +30 mV. The developed cationic liposomes exhibited sustained release profile of payload of 6‑MNA for over >12 h and about five times higher retention in the inflamed animal joints after 24 h (by scintigraphy of the joints) as compared to the plain 6‑MNA solution when administered by IA route. The anti-inflammatory activity of prepared liposomal composition is evaluated by Freund's adjuvant induced arthritic model in rats. The liposomal formulation was well tolerated by all animals indicating good biocompatibility. Further, the cationic liposomal formulation treated group showed decreased erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in comparison to the control and the standard groups in the in vivo study. The improved efficacy of the drug-fortified liposomal formulation was due to the coupled effect of longer retention and sustained release of the active drug 6‑MNA in the joints. From the obtained results it could be concluded that the combined effect of the cationic charge on the drug-fortified liposomes and the inherent affinity of the active agent towards the synovial joint tissues, coupled with slow release of the active drug due to double salt approach at the site of administration could potentially decrease the frequency of IA drug administration. Hence such a formulation could prove to be a therapeutic boon for the management of late stage arthritis.

Intra-Articular Formulation of GE11-PLGA Conjugate-Based NPs for Dexamethasone Selective Targeting-In Vitro Evaluation

Selectively targeted nanoscale drug delivery systems have recently emerged as promising intravenously therapeutic option for most chronic joint diseases. Here, a newly synthetized dodecapeptide (GE11)-polylactide-co-glycolide (PLGA)-based conjugate was used to prepare smart nanoparticles (NPs) intended for intra-articular administration and for selectively targeting Epidermal Growth Factor Receptor (EGFR). GE11-PLGA conjugate-based NPs are specifically uptaken by EGFR-overexpressed fibroblast; such as synoviocytes; which are the primarily cellular component involved in the development of destructive joint inflammation. The selective uptake could help to tune drug effectiveness in joints and to decrease local and systemic side effects. Dexamethasone (DXM) is a glucorticoid drug commonly used in joint disease treatment for both systemic and local administration route. In the present research; DXM was efficiently loaded into GE11-PLGA conjugate-based NPs through an eco-friendly nanoprecipitation method set up for this purpose. DXM loaded GE11-PLGA conjugate-based NPs revealed satisfactory ex vivo cytocompatibility; with proper size (≤150 nm) and good dimensional stability in synovial fluid. Intra-articular formulation was developed embedding DXM loaded GE11-PLGA conjugate-based NPs into thermosetting chitosan-based hydrogel; forming a biocompatible composite hydrogel able to quickly turn from liquid state into gel state at physiological temperature; within 15 min. Moreover; the use of thermosetting chitosan-based hydrogel extends the local release of active agent; DXM.

Injectable liquid polymers extend the delivery of corticosteroids for the treatment of osteoarthritis

Drug delivery strategies generally use inert materials, such as high molecular weight polymers, to encapsulate and control the release rate of therapeutic drugs. Diffusion governs release and depends on the ease of permeation of the polymer alongside the device thickness. Yet in applications such as osteoarthritis, the physiological constraints and limited intra-articular joint space prevent the use of large, solid drug delivery implants. Other investigators have explored the use of micro- and nanoparticle drug delivery systems. However, the small size of the systems limits the total drug that may be encapsulated and its short diffusion distance causes rapid release. Ordinarily, the extremely low diffusivity of a polymer fluid would make this an unsuitable delivery system. Our technology takes advantage of specific molecular interactions between drug and polymer, which can control the rate of release beyond diffusion. With this "affinity-based drug delivery", we have shown that delivery rates from solid polymer can be prolonged from hours and days, to weeks and months. In this paper, we demonstrate that this affinity-based mechanism also applies to low diffusivity fluid-phase polymers. They show release rates that are substantially slower than chemically similar polymers incapable of forming those inclusion complexes. The similarity of this study's liquid polymers to the viscoelastic fluids used in current clinical practice makes it an ample delivery system for osteoarthritic application. We confirmed the capacity of anti-inflammatory delivery of corticosteroids: hydrocortisone, triamcinolone, and dexamethasone; from both solid implants and polymer fluids. Further, we demonstrated that viscoelastic properties are widely tunable, and within the range of native synovial fluid. Lastly, we determined these polymer fluids have no impact on the differentiation of mesenchymal stem cells to cartilage and are not cytotoxic to a common cell line.

Intra-articular clearance of labeled dextrans from naive and arthritic rat knee joints

OBJECTIVE

Determine the effects of arthritis on the trans-synovial clearance of small and large model compounds following local delivery to the knee joint in a rat model.

DESIGN

Intra-articular delivery was studied in rat knee joints in an osteoarthritis model of joint instability (medial collateral ligament and meniscus transection model or MMT). Fluorescently-labeled 10 kDa or 500 kDa dextran was injected in the arthritic or unoperated control (naive) joints 3 weeks after surgical destabilization, and the temporal clearance pattern was evaluated via in vivo regional fluorescence imaging, dextran concentrations in plasma and draining lymph nodes, and by quantification of fluorescence in histological synovium sections. Together these data were used to evaluate the effect of osteoarthritis and solute size on the rate of drug clearance from the joint.

RESULTS

Clearance of 10 kDa dextran from the joint space quantified using in vivo fluorescence imaging of the knee joint region was not significantly different between naive and MMT joints. In contrast, clearance of 500 kDa dextran was significantly reduced for MMT joints when compared to naive joints by fluorescence in vivo imaging. Drug accumulation in lymph nodes and plasma were lower for the 500 kDa dextran as compared to 10 kDa dextran, and lymph node levels were further reduced with the presence of osteoarthritis. Furthermore, synovium was significantly thicker in MMT joints than in naive joints and image analysis of joint tissue sections revealed different trans-synovial distributions of 10 and 500 kDa dextran.

CONCLUSION

Large macromolecules were retained in the arthritic joint longer than in the healthy joint, while smaller molecules were cleared similarly in healthy and arthritic joints. In vivo fluorescence imaging, plasma and lymph node concentrations, and spatial distributions of drug fluorescence identified differences in higher molecular weight clearance between naive and arthritic disease states. Findings may relate to a thickening of synovium for joints with induced arthritis, and support the concept that intra-articular drug delivery effectiveness may vary with the state of joint pathology.

Towards an arthritis flare-responsive drug delivery system

Local delivery of therapeutics for the treatment of inflammatory arthritis (IA) is limited by short intra-articular half-lives. Since IA severity often fluctuates over time, a local drug delivery method that titrates drug release to arthritis activity would represent an attractive paradigm in IA therapy. Here we report the development of a hydrogel platform that exhibits disassembly and drug release controlled by the concentration of enzymes expressed during arthritis flares. In vitro, hydrogel loaded with triamcinolone acetonide (TA) releases drug on-demand upon exposure to enzymes or synovial fluid from patients with rheumatoid arthritis. In arthritic mice, hydrogel loaded with a fluorescent dye demonstrates flare-dependent disassembly measured as loss of fluorescence. Moreover, a single dose of TA-loaded hydrogel but not the equivalent dose of locally injected free TA reduces arthritis activity in the injected paw. Together, our data suggest flare-responsive hydrogel as a promising next-generation drug delivery approach for the treatment of IA.

Attenuation of inflammation and cartilage degradation by sulfasalazine-containing hyaluronic acid on osteoarthritis rat model

The aim of this study was to investigate the effects of a sulfasalazine-containing hyaluronic acid (SASP/HA) systems on in vitro anti-inflammation and the alleviation of cartilage degradation in both lipopolysaccharide (LPS)-stimulated synoviocytes and a rat model of monosodium iodoacetate (MIA)-induced osteoarthritis (OA). The SASP/HA resulted in long-term release of SASP from the SASP/HA for up to 60 days in a sustained manner. In vitro studies performed using real-time polymerase chain reaction (PCR) assay revealed that the SASP/HA was able to effectively and dose-dependently inhibit the mRNA expression levels of pro-inflammatory cytokines such as matrix metalloproteinases-3 (MMP-3), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in LPS-stimulated synoviocytes. In vivo studies showed that intra articular injection of SASP/HA greatly reduced the MIA-stimulated mRNA expression of MMP-3, COX-2, IL-6, and TNF-α in blood. Furthermore, these significant anti-inflammatory effects of SASP/HA contributed markedly to the alleviation of progression of MIA-induced OA and cartilage degradation, as demonstrated by X-ray, micro-computed tomography (micro-CT), gross findings, and histological evaluations. Therefore, our findings indicated that the long-term and sustained delivery of SASP using HA can play a therapeutic role in alleviating inflammation as well as protecting against cartilage damage in OA.

Sustained intra-cartilage delivery of low dose dexamethasone using a cationic carrier for treatment of post traumatic osteoarthritis

Disease-modifying osteoarthritis drugs (DMOADs) should reach their intra-tissue target sites at optimal doses for clinical efficacy. The dense, negatively charged matrix of cartilage poses a major hindrance to the transport of potential therapeutics. In this work, electrostatic interactions were utilised to overcome this challenge and enable higher uptake, full-thickness penetration and enhanced retention of dexamethasone (Dex) inside rabbit cartilage. This was accomplished by using the positively charged glycoprotein avidin as nanocarrier, conjugated to Dex by releasable linkers. Therapeutic effects of a single intra-articular injection of low dose avidin-Dex (0.5 mg Dex) were evaluated in rabbits 3 weeks after anterior cruciate ligament transection (ACLT). Immunostaining confirmed that avidin penetrated the full cartilage thickness and was retained for at least 3 weeks. Avidin-Dex suppressed injury-induced joint swelling and catabolic gene expression to a greater extent than free Dex. It also significantly improved the histological score of cell infiltration and morphogenesis within the periarticular synovium. Micro-computed tomography confirmed the reduced incidence and volume of osteophytes following avidin-Dex treatment. However, neither treatment restored the loss of cartilage stiffness following ACLT, suggesting the need for a combinational therapy with a pro-anabolic factor for enhancing matrix biosynthesis. The avidin dose used caused significant glycosaminoglycan (GAG) loss, suggesting the use of higher Dex : avidin ratios in future formulations, such that the delivered avidin dose could be much less than that shown to affect GAGs. This charge-based delivery system converted cartilage into a drug depot that could also be employed for delivery to nearby synovium, menisci and ligaments, enabling clinical translation of a variety of DMOADs.

Safety of Intra-Articular Implantation of Oligo[Poly(ethylene glycol) Fumarate] Scaffolds into the Rabbit Knee

Implantable biomaterials supporting extended release of pharmacologic agents may permit localized intra-articular delivery of drugs that modulate the fibrotic response to injuries and surgery. Oligo[poly (ethylene glycol)] fumarate (OPF) is an attractive organic carrier, but its safety profile within synovial joints remains unclear. Here, we assessed the safety of OPF sponges using a validated in vivo model of knee arthrofibrosis. A cohort of 102 rabbits was divided into five groups: arthrotomy only (24), arthrotomy with OPF scaffold placement (24), surgically induced contracture (24), surgically induced contracture with OPF scaffold placement (24), and control without any surgical intervention (6). Six rabbits per surgical group were sacrificed at 72 h, 2, 8, and 24 weeks. Outcomes included biomechanical testing of range of motion, histologic analysis of synovial and cartilage tissues, and scaffold degradation. Cartilage histology and biomechanical measurements were comparable between groups with and without OPF. Synovial inflammation scores were similar among most groups with a minimally elevated score in the rabbits with arthrotomy and OPF versus those with arthrotomy alone. Scores for synovial tissues in rabbits with contracture and OPF were clinically equivalent to those with contractures alone. Most animals (92%) retained scaffold fragments at 24 weeks. Thus, OPF scaffolds implanted into native or arthrofibrotic rabbit knees neither induce nor aggravate cartilage damage, synovial inflammation, or contractures. The apparent safety of OPF scaffolds suggests that they are suitable carriers for the controlled delivery of reagents into the intra-articular joint space to treat arthrofibrosis.

Therapeutic effect of ulinastatin on pulmonary fibrosis via downregulation of TGF‑β1, TNF‑α and NF‑κB

Pulmonary fibrosis is a chronic, progressive, lethal lung disease characterized by alveolar cell necrosis and dysplasia of interstitial fibrotic tissue, resulting in loss of lung function and eventual respiratory failure. Previously, glucocorticoid drugs were used to treat this lung disorder. However, positive responses were recorded in less than half of treated patients and the cytotoxicity caused by high dosage treatment is still a concern. The present study investigated whether ulinastatin, a typical urinary trypsin inhibitor that mitigates numerous inflammatory responses, could be a treatment option for lung fibrosis. The results demonstrated that ulinastatin had the ability to ameliorate interstitial fibrosis and alveolar exudates and to protect against lung diseases induced by smoke, irradiation or silica particles. The mechanism of ulinastatin resulted in the downregulation of inflammatory cascades: Transforming growth factor-β1, tumor necrosis factor-α and nuclear factor-κB, as demonstrated by western blotting and ELISA. Ulinastatin treatment with a high dose (100,000 U/kg body weight/day) resulted in an attenuated inflammatory response, and inhibited fibrosis formation in lungs, suggesting that ulinastatin may become a part of a clinical therapeutic strategy.

Chitosan-Based Thermosensitive Hydrogel for Controlled Drug Delivery to the Temporomandibular Joint

Intra-articular injections of hyaluronic acid (HA) and corticosteroids have been extensively used in treating temporomandibular disorders. However, rapid clearance from the site of injection is a major concern that is commonly managed by frequent dosing, which is not without complications. This study aimed to determine the suitability of thermosensitive chitosan-based hydrogels for intra-articular controlled release of drugs in the rabbit temporomandibular joint (TMJ). A series of hydrogels were prepared using different chitosan (Ch) to β-glycerophosphate (β-GP) ratios. The gelation time, swelling ratio, the shape, and surface morphology of the prepared gels were investigated to select the formulation with optimum characteristics. The left TMJ in 13 adult male New Zealand white rabbits was injected with 0.2 mL of Chitosan/β-glycerophosphate/HA while the right TMJ was injected with 0.2 mL of control solution of HA. Hyaluronic acid concentrations in experimental and control groups were measured using Hyaluronan Quantikine Enzyme-Linked Immunosorbent Assay Kit. In vitro characterization showed that both the Ch:β-GP ratio and incorporation of HA had a significant effect on gelation time, degree of swelling, and surface morphology of the hydrogels. No morphological changes were observed in the joints in both groups. The mean concentration of HA in the experimental joints after 7 days (1339.79 ± 244.98 μg/g) was significantly higher than that in the control (474.52 ± 79.36 μg/g). In conclusion, the chitosan-based thermosensitive hydrogel can be considered as a promising controlled drug release system to the TMJ in a rabbit model that would potentially overcome many of the current limitations of intra-articular formulations.

Drug-Bearing Supramolecular Filament Hydrogels as Anti-Inflammatory Agents

We report here on the covalent conversion of the anti-inflammatory agent ketoprofen into self-assembling prodrugs that enable the effective purification of ketoprofen enantiomers, the improved selectivity and potency of ketoprofen, as well as the formation of one-component drug-bearing supramolecular hydrogels. We found that the ketoprofen hydrogelator could exhibit much-enhanced selectivity for cyclooxygenase 2 (COX-2) over COX-1, reduce the concentration of inflammatory cytokines (IL-1 and TNFα), and induce apoptosis in fibroblast-like synoviocytes while maintaining biocompatibility with healthy chondrocytes. In addition, these anti-inflammatory agent-containing hydrogels demonstrated the ability to retain the therapeutic within a joint cavity after intra-articular injection, exhibiting a slow, steady release into the plasma. We believe that upon further optimization these drug-based injectable supramolecular hydrogels could provide the basis for a local treatment strategy for rheumatoid arthritis and similar conditions.

Corticosteroid Injections: A Review of Sex-Related Side Effects

Corticosteroid injections are used as a nonoperative modality to combat acute inflammation when conservative treatments fail. As female patients are regularly seen by orthopedic physicians, it is essential to identify and understand potential sex-related side effects. The aim of this article is to examine available literature for sex-related side effects of orthopedic-related corticosteroid injections. Although the incidence is low, sex-related side effects, such as abnormal menstruation, lactation disturbances, facial flushing, and hirsutism, are associated with corticosteroid injections. Physicians should be aware of these female-specific side effects and relay this information as part of the informed consent process. [Orthopedics. 2017; 40(2):e211-e215.].

Cartilage-targeting drug delivery: can electrostatic interactions help?

Current intra-articular drug delivery methods do not guarantee sufficient drug penetration into cartilage tissue to reach cell and matrix targets at the concentrations necessary to elicit the desired biological response. Here, we provide our perspective on the utilization of charge-charge (electrostatic) interactions to enhance drug penetration and transport into cartilage, and to enable sustained binding of drugs within the tissue's highly negatively charged extracellular matrix. By coupling drugs to positively charged nanocarriers that have optimal size and charge, cartilage can be converted from a drug barrier into a drug reservoir for sustained intra-tissue delivery. Alternatively, a wide variety of drugs themselves can be made cartilage-penetrating by functionalizing them with specialized positively charged protein domains. Finally, we emphasize that appropriate animal models, with cartilage thickness similar to that of humans, must be used for the study of drug transport and retention in cartilage.

Degradation, intra-articular retention and biocompatibility of monospheres composed of [PDLLA-PEG-PDLLA]-b-PLLA multi-block copolymers

In this study, we investigated the use of microspheres with a narrow particle size distribution ('monospheres') composed of biodegradable poly(DL-lactide)-PEG-poly(DL-lactide)-b-poly(L-lactide) multiblock copolymers that are potentially suitable for local sustained drug release in articular joints. Monospheres with sizes of 5, 15 and 30μm and a narrow particle size distribution were prepared by a micro-sieve membrane emulsification process. During in vitro degradation, less crystallinity, higher swelling and accelerated mass loss during was observed with increasing the PEG content of the polymer. The monospheres were tested in both a small (mice/rat) and large animal model (horse). In vivo imaging after injection with fluorescent dye loaded microspheres in mice knees showed that monospheres of all sizes retained within the joint for at least 90days, while the same dose of free dye redistributed to the whole body within the first day after intra-articular injection. Administration of monospheres in equine carpal joints caused a mild transient inflammatory response without any clinical signs and without degradation of the cartilage, as evidenced by the absence of degradation products of sulfated glycosaminoglycans or collagen type 2 in the synovial fluid. The excellent intra-articular biocompatibility was confirmed in rat knees, where μCT-imaging and histology showed neither changes in cartilage quality nor quantity. Given the good intra-articular retention and the excellent biocompatibility, these novel poly(DL-lactide)-PEG-poly(DL-lactide)-b-poly(L-lactide)-based monospheres can be considered a suitable platform for intra-articular drug delivery.

STATEMENT OF SIGNIFICANCE

This paper demonstrates the great potential in intra-articular drug delivery of monodisperse biodegradable microspheres which were prepared using a new class of biodegradable multi-block copolymers and a unique membrane emulsification process allowing the preparation of microspheres with a narrow particle size distribution (monospheres) leading to multiple advantages like better injectability, enhanced reproducibility and predictability of the in vivo release kinetics. We report not only on the synthesis and preparation, but also in vitro characterization, followed by in vivo testing of intra-articular biocompatibility of the monospheres in both a small and a large animal model. The favourable intra-articular biocompatibility combined with the prolonged intra-articular retention (>90days) makes these monospheres an interesting drug delivery platform. What should also be highlighted is the use of horses; a very accurate translational model for the human situation, making the results not only relevant for equine healthcare, but also for the development of novel human OA therapies.

Precise control of drug loading and release of an NSAID–polymer conjugate for long term osteoarthritis intra-articular drug delivery

The synthesis of biocompatible polymer diclofenac conjugates (PDCs) that have a high drug loading and high degree of control over diclofenac (DCF) release is described.

Synthetic nanoscale electrostatic particles as growth factor carriers for cartilage repair

The efficient transport of biological therapeutic materials to target tissues within the body is critical to their efficacy. In cartilage tissue, the lack of blood vessels prevents the entry of systemically administered drugs at therapeutic levels. Within the articulating joint complex, the dense and highly charged extracellular matrix (ECM) hinders the transport of locally administered therapeutic molecules. Consequently, cartilage injury is difficult to treat and frequently results in debilitating osteoarthritis. Here we show a generalizable approach in which the electrostatic assembly of synthetic polypeptides and a protein, insulin‐like growth factor‐1 (IGF‐1), can be used as an early interventional therapy to treat injury to the cartilage. We demonstrated that poly(glutamic acid) and poly(arginine) associated with the IGF‐1 via electrostatic interactions, forming a net charged nanoscale polyelectrolyte complex (nanoplex). We observed that the nanoplex diffused into cartilage plugs in vitro and stimulated ECM production. In vivo, we monitored the transport, retention and therapeutic efficacy of the nanoplex in an established rat model of cartilage injury. A single therapeutic dose, when administered within 48 hr of the injury, conferred protection against cartilage degradation and controlled interleukin‐1 mediated inflammation. IGF‐1 contained in the nanoplex was detected in the joint space for up to 4 weeks following administration and retained bioactivity. The results indicate the potential of this approach as an early intervention therapy following joint injury to delay or even entirely prevent the onset of osteoarthritis.

Intra-articular injection of an antioxidant formulation did not improve structural degeneration in a rat model of post-traumatic osteoarthritis

Background/objective

Oxidative stress plays an important role in osteoarthritis (OA), causing inflammation and matrix degradation in joints. Previous studies have shown that antioxidants such as quercetin and vitamin C are potential candidates for treating OA. We aimed to determine whether a formulation of quercetin and vitamin C, together with an iron chelator, could retard OA progression in a post-traumatic OA rat model.

Methods

Twelve rats received anterior cruciate ligament transection for OA induction. At 20 weeks postoperation, weekly intra-articular injection of 50 μL of either saline or a formulation of quercetin dehydrate, sodium-L-ascorbate, and deferoxamine mesylate was given consecutively for 4 weeks (n = 5). Gait analysis was performed at pretreatment, and at 1 week and 5 weeks post-treatment. Microcomputed tomography scanning and histological scoring were performed at 5 weeks post-treatment.

Results

Gait analysis showed that intra-articular injections of antioxidant formulation did not improve pain-associated Limb Idleness Index over time (p = 0.449, Friedman test). However, at 5 weeks post-treatment, the treatment group exhibited a significantly lower Limb Idleness Index than the control group (p = 0.047, Mann–Whitney U test). At 5 weeks post-treatment, microcomputed tomography analysis revealed that there was no difference in any parameter between the treatment and control groups (p > 0.05, Student t test). Severe OA histopathological changes were found in both groups. The Osteoarthritis Research Society International scores of the treatment and control groups were 20 (range, 20–26) and 20 (range, 9–26), respectively (p = 0.382, Mann–Whitney U test).

Conclusion

Intra-articular injection of an antioxidant formulation containing quercetin, vitamin C, and deferoxamine did not retard OA progression in advanced-stage OA. Future studies should aim to determine whether giving antioxidants in early OA, with prolonged drug retention, would be effective in retarding OA progression.

Ibuprofen-loaded porous microspheres suppressed the progression of monosodium iodoacetate-induced osteoarthritis in a rat model

The objectives of this study were (1) to fabricate ibuprofen-loaded porous microspheres (IBU/PMSs), (2) to evaluate the in vitro anti-inflammatory effects of the microspheres using LPS-induced inflammation in cultured synoviocytes, and (3) to evaluate the in vivo effect of the IBU/PMSs on the progression of monosodium iodoacetate (MIA)-induced osteoarthritis (OA) in a rat model. A dose-dependent in vitro anti-inflammatory effect on pro-inflammatory cytokine markers (matrix metallopeptidase-3 (MMP-3), matrix metallopeptidase-13 (MMP-13), cyclooxygenase-2 (COX-2), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5)), interleukin-6 (IL-6), and tumor necrosis factor (TNF-α) was observed by confirming with real-time PCR analyses. In vivo, treatment with IBU/PMSs reduced MIA-stimulated mRNA expression of MMP-3, MMP-13, COX-2, ADAMTS-5, IL-6, and TNF-α in rat synoviocytes. In addition, we demonstrated that intra-articular IBU/PMSs suppressed the progression of MIA-induced OA in the rat model via anti-inflammatory mechanisms. In conclusion, IBU/PMSs are a promising therapeutic material to control the pain and progression of OA.

Long-Acting Diclofenac Ester Prodrugs for Joint Injection: Kinetics, Mechanism of Degradation, and In Vitro Release From Prodrug Suspension

A prodrug approach for local and sustained diclofenac action after injection into joints based on ester prodrugs having a pH-dependent solubility is presented. Inherent ester prodrug properties influencing the duration of action include their pH-dependent solubility and charge state, as well as susceptibility to undergo esterase facilitated hydrolysis. In this study, physicochemical properties and pH rate profiles of 3 diclofenac ester prodrugs differing with respect to the spacer carbon chain length between the drug and the imidazole-based promoiety were determined and a rate equation for prodrug degradation in aqueous solution in the pH range 1-10 was derived. In the pH range 6-10, the prodrugs were subject to parallel degradation to yield diclofenac and an indolinone derivative. The prodrug degradation was found to be about 6-fold faster in 80% (vol/vol) human plasma as compared to 80% (vol/vol) human synovial fluid with 2-(1-methyl-1H-imidazol-2-yl)ethyl 2-(2-(2,6 dichlorophenyl)amino)phenylacetate being the poorest substrate toward enzymatic cleavage. The conversion and release of parent diclofenac from prodrug suspensions in vitro were studied using the rotating dialysis model. The results suggest that it is possible to alter and control dissolution and reconversion behavior of the diclofenac prodrugs, thus making the prodrug approach feasible for local and sustained diclofenac action after joint injection.

Injectable thermosensitive gelling delivery system for the sustained release of lidocaine

BACKGROUND

Patients undergoing arthroplasty require appropriate postsurgical pain relief. Analgesia is typically achieved through bolus doses of short-acting local anesthetics and with oral analgesics such as opiates, which are associated with systemic side effects. By formulating an injectable thermosensitive gelling system containing lidocaine, sustained and local delivery can be achieved following a single administration.

RESULTS

Poloxamer-based thermosensitive gelling formulations were prepared. Altering the weight ratios of poloxamers affected the sol-to-gel transition temperature, mechanical and rheological properties and in vitro drug release. Desirable formulations gelled between 28 and 33°C providing sustained release of lidocaine over 48 h.

CONCLUSION

Thermosensitive gelling systems are promising for sustained drug release following patient administration and may be beneficial in addressing postoperative pain.

Particle-based technologies for osteoarthritis detection and therapy

Osteoarthritis (OA) is a disease characterized by degradation of joints with the development of painful osteophytes in the surrounding tissues. Currently, there are a limited number of treatments for this disease, and many of these only provide temporary, palliative relief. In this review, we discuss particle-based drug delivery systems that can provide targeted and sustained delivery of imaging and therapeutic agents to OA-affected sites. We focus on technologies such as polymeric micelles and nano-/microparticles, liposomes, and dendrimers for their potential treatment and/or diagnosis of OA. Several promising studies are highlighted, motivating the continued development of delivery technologies to improve treatments for OA.

Repositioning Clofazimine as a Macrophage-Targeting Photoacoustic Contrast Agent

Photoacoustic Tomography (PAT) is a deep-tissue imaging modality, with potential clinical applications in the diagnosis of arthritis, cancer and other disease conditions. Here, we identified Clofazimine (CFZ), a red-pigmented dye and anti-inflammatory FDA-approved drug, as a macrophage-targeting photoacoustic (PA) imaging agent. Spectroscopic experiments revealed that CFZ and its various protonated forms yielded optimal PAT signals at wavelengths −450 to 540 nm. CFZ’s macrophage-targeting chemical and structural forms were detected with PA microscopy at a high contrast-to-noise ratio (CNR > 22 dB) as well as with macroscopic imaging using synthetic gelatin phantoms. In vivo, natural and synthetic CFZ formulations also demonstrated significant anti-inflammatory activity. Finally, the injection of CFZ was monitored via a real-time ultrasound-photoacoustic (US-PA) dual imaging system in a live animal and clinically relevant human hand model. These results demonstrate an anti-inflammatory drug repurposing strategy, while identifying a new PA contrast agent with potential applications in the diagnosis and treatment of arthritis.

Particles for Local Delivery of Proteins Using Intra-Articular Route

Designing a vehicle for local delivery of proteins using intra-articular route is an attractive option to minimize the adverse effects associated with systemic exposure and to maximize the efficacy. Slowly dissolving silylated microparticles are designed with specific size and shape that are capable of extending the retention time of a model protein (bovine serum albumin) in the murine knee joint. No cytotoxicity is observed for the reconstituted formulation when tested against synovial fibroblasts and RAW 264.7 macrophages.