Oral Versus Topical Diclofenac Sodium in the Treatment of Osteoarthritis

Pharmacotherapy for osteoarthritis-related pain: current and emerging therapies

INTRODUCTION

Osteoarthritis (OA) related pain has affected millions of people worldwide. However, the current pharmacological options for managing OA-related pain have not achieved a satisfactory effect.

AREAS COVERED

This narrative review provides an overview of the current and emerging drugs for OA-related pain. It covers the drugs' mechanism of action, safety, efficacy, and limitations. The National Library of Medicine (PubMed) database was primarily searched from 2000 to 2024.

EXPERT OPINION

Current treatment options are limited and suboptimal for OA pain management. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are the recognized and first-line treatment in the management of OA-related pain, and other drugs are inconsistent recommendations by guidelines. Emerging treatment options are promising for OA-related pain, including nerve growth factor (NGF) inhibitors, ion channel inhibitors, and calcitonin gene-related peptide (CGRP) antagonists. Besides, drugs repurposing from antidepressants and antiepileptic analgesics are shedding light on the management of OA-related pain. The management of OA-related pain is challenging as pain is heterogeneous and subjective. A more comprehensive strategy combined with non-pharmacological therapy needs to be considered, and tailored management options to individualized patients.

n-3 polyunsaturated fatty acids alleviate the progression of obesity-related osteoarthritis and protect cartilage through inhibiting the HMGB1-RAGE/TLR4 signaling pathway

Osteoarthritis (OA) is a common joint degenerative disease. There is currently no cure for OA. Dietary fatty acids have potential value in the prevention and treatment of OA. n-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory effects, but their anti-OA mechanism remains unclear. High-mobility group box 1 (HMGB1) promotes inflammation and participates the pathogenesis of OA. The purpose of this study was to investigate the protective effect of n-3 PUFAs on cartilage and whether n-3 PUFAs could exert an anti-OA effect through inhibiting HMGB1-RAGE/TLR4 signaling pathway. We established an obesity-related post-traumatic OA mice model and an in vitro study was conducted to explore the regulatory mechanism of n-3 PUFAs on HMGB1 and its signal pathway against OA. We found that diet rich in n-3 PUFAs alleviated OA-like lesions of articular cartilage with the decrease of HMGB1-RAGE/TLR4 signaling protein in mice. In SW1353 cells, DHA significantly reduced the expression of HMGB1-RAGE/TLR4 signaling protein which was up-regulated by IL-1β stimulation. HMGB1 overexpression reversed the inhibitory effect of DHA on HMGB1-RAGE/TLR4 signaling pathway. The activation of SIRT1 may participate the inhibitory effect of DHA on HMGB1-RAGE/TLR4 signaling pathway. In conclusion, n-3 PUFAs could attenuate the progression of obesity-related OA and exert protective effect on cartilage by inhibiting HMGB1-RAGE/TLR4 signaling pathway, which may be associated with the activation of SIRT1. Dietary n-3 PUFAs supplements can be considered as a potential therapeutic substance for OA.

Formulation and investigation of hydrogels containing an increased level of diclofenac sodium using risk assessment tools

Transdermal delivery of active ingredients is a challenge for pharmaceutical technology due to their inadequate penetration properties and the barrier function of the skin. The necessity of painless, effective, topical therapy for the aging population is growing, and a variety of diclofenac sodium-containing semi-solid preparations are available to alleviate the symptoms of these ailments. Our purpose was to formulate a novel composition with higher drug content to enhance drug release and permeation, thereby providing more effective therapy. Another goal was to maintain the concentration of the organic solvent mixture below 30%, to protect the skin barrier. Firstly, literature and market research were conducted, based on which the appropriate excipients for the target formulation were selected. Solubility tests were conducted with binary and ternary mixtures. As a result, the optimal ternary mixture was chosen. Hydrogels containing 1, 5, and 7% of diclofenac sodium were prepared and the stability of the formulations were studied by microscopic measurements and cytotoxicity test were carried out of the components also. The release and permeation of diclofenac sodium were investigated in different concentrations. It can be concluded that we have succeeded in preparing a topically applicable stable diclofenac sodium hydrogel with higher concentration, drug release, and improved skin permeation than the formulations available on the market.

Efficacy of mixed diclofenac solutions against root canal biofilms

The objective of this research was to evaluate the efficacy of diclofenac sodium solutions, with or without cetrimide (CTR) added, against polymicrobial root canal biofilms grown in dentin specimens. The study groups were: (1) 5% diclofenac sodium (DCS); (2) 2.5% DCS; (3) 2.5% DCS + 0. 2% CTR; (4) 2.5% DCS + 0.4% CTR and (5) 0.9% saline solution (SS) as the control. After 5 min of solution contact with the biofilms, the antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay as well as confocal laser scanning microscopy (CLSM). Microbial quantification was indicated as the percentage reduction of relative light units (RLUs) for the ATP assay, the Log10 total biovolume and the viability percentage (green cells) for CLSM. Solutions of 2.5% DCS + 0.4% CTR and 5% DCS showed the highest antimicrobial efficacy. Cetrimide increased the antibiofilm activity of diclofenac sodium against endodontic biofilms.

Enteric-coating film effect on the delayed drug release of pantoprazole gastro-resistant generic tablets

Background: Enteric coating films in acidic labile tablets protect the drug molecule from the acidic environment of the stomach. However, variations in the excipients used in the coating formulation may affect their ability to provide adequate protection. This study is the first to investigate the potential effects of coating materials on the protective functionality of enteric coating films for pantoprazole (PNZ) generic tablets after their recall from the market. Methods: A comparative analysis was conducted between generic and branded PNZ products, using pure drug powder for identification. The in vitro release of the drug was evaluated in different pH media. The study also utilized various analytical and thermal techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and confocal Raman microscopy. Results: The in vitro assessment results revealed significant variations in the release profile for the generic product in acidic media at 120 min. DSC and TGA thermal profile analyses showed slight variation between the two products. XRD analysis exhibited a noticeable difference in peak intensity for the generic sample, while SEM revealed smaller particle sizes in the generic product. The obtained spectra profile for the generic product displayed significant variation in peaks and band intensity, possibly due to impurities. These findings suggest that the excipients used in the enteric coating film of the generic product may have affected its protective functionality, leading to premature drug release in acidic media. Additionally, the presence of polysorbate 80 (P-80) in the brand product might improve the properties of the enteric coating film due to its multi-functionality. Conclusions: In conclusion, the excipients used in the brand product demonstrated superior functionality in effectively protecting the drug molecule from acidic media through the enteric coating film, as compared to the generic version.

Nanosuspension-Based Dissolvable Microneedle Arrays to Enhance Diclofenac Skin Delivery

Applying a formulation on the skin represents a patient-acceptable and therapeutically effective way to administer drugs locally and systemically. However, the stratum corneum stands as an impermeable barrier that only allows a very limited number of drugs to be distributed in the underlying tissues, limiting the feasibility of this administration route. Microneedle arrays are minimally invasive platforms that allow the delivery of drugs within/across the skin through the temporary mechanical disruption of the stratum corneum. In this work, microneedle arrays were combined with nanosuspensions, a technology for solubility enhancement of water insoluble molecules, for the skin delivery of diclofenac. Nanosuspensions were prepared using a top-down method and loaded in the tips of 500 µm or 800 µm high microneedles. The quality of the combined platform was assessed using electron microscopy and spectroscopic and calorimetry techniques, demonstrating the ability to load high amounts of the hydrophobic drug and the compatibility between excipients. Lastly, the application of nanosuspension-loaded microneedles on the skin in vitro allowed the delivery of diclofenac within and across the stratum corneum, proving the potential of this combination to enhance skin delivery of scarcely soluble drugs.

A new osteogenic protein isolated from Dioscorea opposita Thunb accelerates bone defect healing through the mTOR signaling axis

Delayed bone defect repairs lead to severe health and socioeconomic impacts on patients. Hence, there are increasing demands for medical interventions to promote bone defect healing. Recombinant proteins such as BMP-2 have been recognized as one of the powerful osteogenic substances that promote mesenchymal stem cells (MSCs) to osteoblast differentiation and are widely applied clinically for bone defect repairs. However, recent reports show that BMP-2 treatment has been associated with clinical adverse side effects such as ectopic bone formation, osteolysis and stimulation of inflammation. Here, we have identified one new osteogenic protein, named 'HKUOT-S2' protein, from Dioscorea opposita Thunb. Using the bone defect model, we have shown that the HKUOT-S2 protein can accelerate bone defect repair by activating the mTOR signaling axis of MSCs-derived osteoblasts and increasing osteoblastic biomineralization. The HKUOT-S2 protein can also modulate the transcriptomic changes of macrophages, stem cells, and osteoblasts, thereby enhancing the crosstalk between the polarized macrophages and MSCs-osteoblast differentiation to facilitate osteogenesis. Furthermore, this protein had no toxic effects in vivo. We have also identified HKUOT-S2 peptide sequence TKSSLPGQTK as a functional osteogenic unit that can promote osteoblast differentiation in vitro. The HKUOT-S2 protein with robust osteogenic activity could be a potential alternative osteoanabolic agent for promoting osteogenesis and bone defect repairs. We believe that the HKUOT-S2 protein may potentially be applied clinically as a new class of osteogenic agent for bone defect healing.

RNA-binding proteins in degenerative joint diseases: A systematic review

RNA-binding proteins (RBPs), which are conserved proteins comprising multiple intermediate sequences, can interact with proteins, messenger RNA (mRNA) of coding genes, and non-coding RNAs to perform different biological functions, such as the regulation of mRNA stability, selective polyadenylation, and the management of non-coding microRNA (miRNA) synthesis to affect downstream targets. This article will highlight the functions of RBPs, in degenerative joint diseases (intervertebral disc degeneration [IVDD] and osteoarthritis [OA]). It will reviews the latest advancements on the regulatory mechanism of RBPs in degenerative joint diseases, in order to understand the pathophysiology, early diagnosis and treatment of OA and IVDD from a new perspective.

Ginsenoside Rb1 from Panax ginseng attenuates monoiodoacetate-induced osteoarthritis by inhibiting miR-21-5p/FGF18-mediated inflammation

Ginsenoside Rb1 (Rb1) is a major active compound in Panax ginseng and has shown considerable anti-inflammation effects. Osteoarthritis (OA) is one of the major degenerative disorders affecting the knee. MiR-21-5p is a potential therapeutic target for OA treatment. This study explored the anti-OA effects of Rb1 by focusing on its interaction with the miR-21-5p/FGF18 axis. OA was induced in rats using monoiodoacetate (MIA) and managed with Rb1. Then, changes in the histological structure and miR-21-5p-mediated signaling pathway were measured in joint tissues. The role of miR-21-5p/FGF18 in the anti-OA effects of Rb1 was confirmed by inducing its levels in rats and chondrocytes. Rb1 improved the histological structure and suppressed the production of cytokines in joint tissues. At the molecular level, Rb1 down-regulated miR-12-5p levels and up-regulated FGF18 levels. In chondrocytes, Rb1 increased cell viability, suppressed inflammation, down-regulated miR-21-5p levels, and up-regulated FGF18 levels. The restored level of miR-21-5p compromised the anti-OA effects of Rb1. In a nutshell, our study reported that the anti-OA effects of Rb1 relied on the inhibited expression of miR-21-5p. PRACTICAL APPLICATIONS: Ginsenoside Rb1 (Rb1) is a major active compound in Panax ginseng and has shown considerable anti-osteoarthritis (OA) effects. The current study not only relates the anti-OA function of ginsenoside Rb1 with microRNA but also provides valuable information for exploring novel targets for the development the anti-OA strategies.

Effects of Different Nonsteroidal Anti-Inflammatory Drugs Combined with Platelet-Rich Plasma on Inflammatory Factor Levels in Patients with Osteoarthritis

Objective. To investigate the effects of different nonsteroidal anti-inflammatory drugs combined with platelet-rich plasma on inflammatory factor levels in patients with osteoarthritis. Methods. The clinic data of 120 patients with osteoarthritis who were treated in our hospital (June 2019-June 2021) were retrospectively reviewed. All the patients were given platelet-rich plasma. According to the different nonsteroidal anti-inflammatory drugs the patients received, they were equalized into diclofenac sodium group, celecoxib group, and iguratimod group, with 40 cases in each group. After treatment, the patients’ clinical efficacy was compared and analyzed. Results. After treatment, the pain degrees of the patients in the three groups were gradually reduced. After 4 weeks and 8 weeks of treatment, the statistical differences in the scores of Visual Analogue Scale (VAS) were found among the three groups. Specifically, compared with the other two groups, the iguratimod group had remarkably lower VAS scores ( $P<0.05$ ) and the celecoxib group had signally lower VAS scores compared with the diclofenac sodium group ( $P<0.05$ ). After treatment, the inflammatory factor levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) in the diclofenac sodium group were observably higher compared with the celecoxib group ( $P<0.05$ ), and the inflammatory factor levels in the celecoxib group were remarkably higher compared with the iguratimod group ( $P<0.05$ ). Before treatment, no notable difference in the Lysholm scores was found among the three groups, and the patients’ knee joint function was gradually improved after treatment. To be specific, after 4 and 8 weeks of treatment, the iguratimod group had observably higher Lysholm scores compared with the other two groups ( $P<0.05$ ), and the celecoxib group had signally higher Lysholm scores compared with the diclofenac sodium group ( $P<0.05$ ). The iguratimod group got markedly lower Western Ontario and McMaster Universities (WOMAC) score compared with the celecoxib group ( $P<0.05$ ); Compared with the diclofenac sodium group, the celecoxib group got remarkably lower WOMAC score ( $P<0.05$ ). During treatment, few patients suffered from mild gastrointestinal discomfort and hepatic dysfunction in the three groups, and no other severe adverse reactions were found. No statistical difference in the total incidence of adverse reactions among the three groups was observed ( $P>0.05$ ). Conclusion. The combination of nonsteroidal anti-inflammatory drugs with platelet-rich plasma can further reduce the inflammatory reactions of the patients with osteoarthritis and improve their knee joint function. Significantly, the iguratimod, with high safety, has observably better effects on inhibiting inflammatory factors and improving knee joint function compared with diclofenac sodium and celecoxib.

Ionic Liquids for Enhanced Drug Delivery: Recent Progress and Prevailing Challenges

Ionic liquids (ILs) are a class of nonmolecular compounds composed only of ions. Compared with traditional organic solvents, ILs have the advantages of wide chemical space, diverse and flexible structures, negligible vapor pressure, and high thermal stability, which make them widely used in many fields of modern science, such as chemical synthesis and catalytic decomposition, electrochemistry, biomass conversion, and biotransformation biotechnology. Because of their special characteristics, ILs have been favored in the pharmaceutical field recently, especially for the development of efficient drug delivery systems. So far, ILs have been successfully designed to promote the dissolution of poorly soluble drugs and the destruction of physiological barriers, such as the tight junction between the stratum corneum and the intestinal epithelium. In addition, ILs can also be combined with other drug strategies to stabilize the structure of small molecules. This Review mainly introduces the application of ILs in drug delivery, emphasizes the potential mechanism of ILs, and presents the key research directions of ILs in the future.

Cytocompatible drug delivery hydrogels based on carboxymethylagarose/chitosan pH-responsive polyelectrolyte complexes

Several drugs are chemically unstable in the gastric environment and have low bioavailability restricted by intestinal absorption, which motivates the development of alternative routes for drug release, such as transdermal drug carriers for drug delivery to specific areas of the skin. Herein, novel polyelectrolyte complexes (PEC) consisting of carboxymethylagarose (CMA) and chitosan (CS) were prepared. pH-responsive CMA/CS hydrogels were obtained by mixing CMA and CS at various weight ratios. Swelling ratio was modulated by varying the CMA and CS weight ratio, and the highest swelling values were achieved for 2:1 wt% hydrogels at 25 °C and pH 6.0. PEC films were characterized by ATR-FTIR spectroscopy, TGA, DSC, and SEM. Results indicated that CMA and CS were successfully crosslinked by ionic complexation. As a model drug, diclofenac sodium (DS) was loaded in CMA/CS PECs. Association efficiency and loading capacity were ca. 69% and 79%, respectively, exhibiting 67% cumulative release after 72 h at 37 °C and pH 6.0 through Fickian diffusion mechanism. Viability assay of immortalized human keratinocyte (HaCat) cells showed ca. 100% survival in the presence of hydrogels and DS. Therefore, this work suggests that CMA/CS PECs can be applied as pH-responsive carriers for dermal drug delivery.

Development challenges for carcinogenicity risk assessments of topical drugs

The nonclinical safety package to support development and approval of drugs intended to be administered by topical application generally follows International Council for Harmonisation multidisciplinary 3 (ICH M3) and topic specific safety (ICH S) guidances. However, some aspects of topical drug development may require case-by-case determination of nonclinical safety strategies. The necessity to conduct a dermal rodent carcinogenicity study is one such example that is not considered an obligate component of a nonclinical safety data package for drug approval. While absence of systemic exposure, as stated in ICH M3, is a primary reason to forego a dermal carcinogenicity assessment, there may also be other factors for consideration in determining the need for a life-time carcinogencity study by dermal route to aid in the overall human cancer risk assessment. We therefore reviewed nonclinical carcinogencity data packages from drugs approved by the FDA or PMDA over a ~25 year time period to evaluate outcomes of oral versus topical carcinogencity studies and to understand their utility for informing the overall human risk assessment. We also discuss various other properties of topical small molecules that could impact the decisions to conduct a dermal life-time rodent carcinogenicity study. Collectively, the need to conduct 2-year dermal carcinogenicity studies in rodents should be determined case-by-case and consider scientific factors such existing systemic toxicity and carcinogenicity study data, anticipated drug exposures in skin, skin evaluation from the chronic minipig toxicity study, and genetic toxicity profile.

Comparison of the Efficacy and Safety of Ketoprofen Plaster and Diclofenac Plaster for Osteoarthritis-Related Knee Pain: A Multicenter, Randomized, Active-Controlled, Open-Label, Parallel-Group, Phase III Clinical Trial

PURPOSE

To compare the efficacy and safety of ketoprofen plasters and diclofenac plasters after 3 weeks of administration in patients with osteoarthritis-related knee pain.

METHODS

This multicenter, randomized, active-controlled, open-label, parallel-group, noninferiority phase III study randomized 236 adults with osteoarthritis-related knee pain for 3 weeks with ketoprofen plaster 30 mg twice daily (n = 118) or diclofenac plaster 15 mg once daily (n = 118). The primary efficacy end point was the mean change from baseline to week 3 in the mean knee pain intensity score during walking, as measured by a 100-mm visual analog scale with a predefined noninferiority margin of 10.0 mm. Secondary end points included changes in knee pain intensity score during walking (weeks 1 and 2) and at rest (weeks 1, 2, and 3), Knee Injury and Osteoarthritis Outcome Score, Patient Global Impression of Improvement scale assessments, and frequency of rescue medication use after 2 and 3 weeks of treatment.

FINDINGS

A total of 223 patients (115 in the ketoprofen group and 108 in the diclofenac group) were included in the per-protocol analysis. After 3 weeks of treatment, the least squares mean change from baseline in knee pain intensity scores during walking was -35.9 (95% CI, -39.7 to -32.2) in the ketoprofen group and -31.7 (95% CI, -35.5 to -27.9) in the diclofenac group, with noninferiority found (least squares mean difference, -4.2; 95% CI, -9.6 to 1.1). Ketoprofen significantly (P < 0.05) reduced the pain intensity score at rest after 2 and 3 weeks of treatment compared with diclofenac. No statistically significant difference was found between the groups in terms of changes in pain intensity score during walking at weeks 1, 2, and 3. The mean Patient Global Impression of Improvement score was statistically significant (P < 0.001) in favor of ketoprofen after 2 and 3 weeks of treatment. In addition, the Knee Injury and Osteoarthritis Outcome Score improved in both groups, and no statistically significant difference was found between the groups in terms of frequency of rescue medication use. The overall adverse event profile of the groups was similar, and no difference was found in skin reaction rates between the 2 groups.

IMPLICATIONS

Ketoprofen plasters can be effectively and safely administered to patients with osteoarthritis-related knee pain.

Sublethal diclofenac induced oxidative stress, neurotoxicity, molecular responses and alters energy metabolism proteins in Nile tilapia, Oreochromis niloticus

Reports have shown that residues of pharmaceuticals and their metabolites can pose toxicological threats to organisms living in aquatic ecosystem. Nile tilapia, Oreochromis niloticus, was exposed at 0.17, 0.34, and 0.68 mg L^-1 of diclofenac up to 60 days in a renewal static bioassay system. Antioxidant enzymes reactions, molecular responses, activities of energy metabolism proteins, and the neurotoxic potentials of the drug in the brain and fish muscle were evaluated. Antioxidant enzyme activities such as superoxide dismutase, glutathione-S-transferase, and also fructose 1, 6 bisphosphatase and glucose-6-phosphate dehydrogenase as well as the levels of lipid peroxidation and protein carbonyl were elevated, while glutathione peroxidase, total reduced glutathione, and acetylcholinesterase in the brain and muscles of the treated groups were significantly inhibited in a dose-dependent association. Expression of superoxide dismutase (sod), catalase (cat), and heat shock proteins (hsp 70) genes in brain and muscle tissues was up-regulated. Continuous treatment with sublethal diclofenac for a long time can induce oxidative imbalance, cause neurotoxicity, and alter the expression of genes related to stress in Nile tilapia, suggesting the use of these biomarkers in monitoring the adverse effects the pharmaceuticals could cause to organisms in aquatic ecosystem for possible mitigation.

Strategies for transdermal drug delivery against bone disorders: A preclinical and clinical update

The transdermal drug delivery system is an exceptionally safe and well-tolerable therapeutic approach that has immense potential for delivering active components against bone-related pathologies. However, its use is limited in the current clinical practices due to the low skin permeability of most active drugs in the formulation. Thus, innovations in the methodologies of skin permeation enhancement techniques are suggested to overcome this limitation. Although various transdermal drug delivery systems are studied to date, there are insufficient studies comparing the therapeutic efficacy of transdermal delivery systems to oral delivery systems. Thus, creating a decision-making dilemma between oral or transdermal therapies. Therefore, a timely review is inevitable to develop a platform for future researchers to develop next-generation transdermal drug delivery strategies against skeletal diseases that must be convenient and cost-effective for the patients with improved therapeutic efficacy. Here, we will outline the most recent strategies that can overcome the choice limitation of the drug and enhance the transdermal adsorption of various types of drugs to treat bone disorders. For the first time, in this review paper, we will highlight the preclinical and clinical studies on the different transdermal delivery methods. Thus, providing insight into the current therapeutic approaches and suggesting new directions for the advancements in transdermal drug delivery systems against bone disorders.

A probiotic intervention on pain hypersensitivity and microbiota composition in patients with osteoarthritis pain: Study protocol for a randomized controlled trial

OBJECTIVES

This study aims to examine the effects of probiotics on pain hypersensitivity at the end of a six-week intervention program in patients with osteoarthritis (OA)-related pain.

PATIENTS AND METHODS

This double-blind randomized controlled clinical trial with two parallel arms will be conducted between January 2021 and July 2022. At least 30 participants (age range, 50 to 90 years) of both sexes with a diagnosis of symptomatic hip or knee (Kellgren-Lawrence scale ≥3) will be recruited in each arm (total n=60) to achieve adequate statistical power in the analyses. The intervention will be administered for six weeks followed by a four-week follow-up period. The experimental group will receive a probiotic product plus the usual medical care. The control group will receive a probiotical sham plus the usual medical care. Assessment points will be measured at baseline, end of intervention, and one-month post-intervention. The outcomes of this intervention will be a change in visual analog scale pain and the gut microbiota composition. Group by time effects will be compared using mixed-model analysis of variance.

CONCLUSION

A reduction in pain hypersensitivity in patients with knee OA-related pain could suggest an involvement of microbiota, or part of it, in chronic pain state mechanisms.

Hyaluronan-Loaded Liposomal Dexamethasone-Diclofenac Nanoparticles for Local Osteoarthritis Treatment

Osteoarthritis (OA) remains one of the common degenerative joint diseases and a major cause of pain and disability in older adult individuals. Oral administration of non-steroidal anti-inflammatory drugs (NSAIDs) (such as diclofenac, DIC) or intra-articular injected gluco-corticosteroids (such as dexamethasone, DEX) were the conventional treatment strategies for OA to reduce joint pain. Current limitations for both drugs including severe adverse effects with risks of toxicity were noted. The aim of the present study was to generate a novel OA treatment formulation hyaluronic acid (HA)-Liposomal (Lipo)-DIC/DEX to combat joint pain. The formulation was prepared by constructing DIC with DEX-loaded nanostructured lipid carriers Lipo-DIC/DEX mixed with hyaluronic acid (HA) for prolonged OA application. The prepared Lipo-DIC/DEX nanoparticles revealed the size as 103.6 ± 0.3 nm on average, zeta potential as −22.3 ± 4.6 mV, the entrapment efficiency of 90.5 ± 5.6%, and the DIC and DEX content was 22.5 ± 4.1 and 2.5 ± 0.6%, respectively. Evidence indicated that HA-Lipo-DIC/DEX could reach the effective working concentration in 4 h and sustained the drug-releasing time for at least 168 h. No significant toxicities but increased cell numbers were observed when HA-Lipo-DIC/DEX co-cultured with articular chondrocytes cells. Using live-animal In vivo imaging system (IVIS), intra-articular injection of each HA-Lipo-DIC/DEX sufficed to reduce knee joint inflammation in OA mice over a time span of four weeks. Single-dose injection could reduce the inflammation volume down to 77.5 ± 5.1% from initial over that time span. Our results provided the novel drug-releasing formulation with safety and efficiency which could be a promising system for osteoarthritis pain control.

Nanosuspensions and Microneedles Roller as a Combined Approach to Enhance Diclofenac Topical Bioavailability

Topical application of the anti-inflammatory drug diclofenac (DCF) reduces the severity of systemic unwanted effects compared to its oral administration. A number of transdermal formulations are available on the market and routinely used in clinical and home-care settings. However, the amount of DCF delivered across the skin remains limited and often insufficient, thus making the oral route still necessary for achieving sufficient drug concentration at the inflamed site. In attempting to improve the transdermal penetration, we explored the combined use of DCF nanosuspensions with a microneedle roller. Firstly, DCF nanosuspensions were prepared by a top-down media milling method and characterized by spectroscopic, thermal and electron microscopy analyses. Secondly, the pore-forming action of microneedle rollers on skin specimens (ex vivo) was described by imaging at different scales. Finally, DCF nanosuspensions were applied on newborn pig skin (in vitro) in combination with microneedles roller treatment, assessing the DCF penetration and distribution in the different skin layers. The relative contribution of microneedle length, nanosuspension stabilizer and application sequence could be identified by systemically varying these parameters.

Laser-induced transient skin disruption to enhance cutaneous drug delivery

The use of pressure waves (PW) to disrupt the stratum corneum (SC) temporarily is an effective strategy to increase the deposition of drug molecules into the skin. However, given the rather modest outcomes when compared with ablation-assisted drug delivery, its potential has been underestimated. Accordingly, the aim of this study was to examine the impact of Resonant Amplitude Waves (RAWs) on increasing cutaneous delivery. RAW phenomena are triggered by focusing a high-peak-power pulsed laser onto an appropriate transducer structure, under space- and time-controlled resolution. In order to determine the optimal conditions for the generation and use of RAWs, a screening of laser parameters setting and an analysis of different geometries of the impact pattern over diverse materials used as transducers was performed, analyzing the footprint of the RAW waves in an agarose gel. The results obtained were then checked and fine-tuned using human skin samples instead of agarose. Furthermore, ex vivo experiments were carried out to characterize the effect of the RAWs in the cutaneous delivery of diclofenac (DIC) and lidocaine (LID) administered in the form of gels. The application of RAWs resulted in an increased delivery of DIC and LID to the skin, whose intensity was dependent on the composition of the formulation. In fact, the maximum observed for DIC and LID in short-time experiments (39.1 ± 11.1 and 153 ± 16 µg/cm², respectively) was comparable to those observed using ablation-assisted drug delivery under the same conditions. In conclusion, the combination of RAWs with specific formulation strategies is a feasible alternative for the cutaneous delivery of drug candidates when short onset of action is required.

Exacerbation of diclofenac-induced gastroenterohepatic damage by concomitant exposure to sodium fluoride in rats: protective role of luteolin

NSAID-induced gastrointestinal toxicity is associated with non-selective inhibition of cyclooxygenase (COX)-mediated synthesis of prostaglandins. Fluoride salts, known to stimulate COX-2 synthesis, have also been associated with gastrointestinal damage. The effects of fluoride treatment on NSAID toxicity are, however, yet to be clarified. This study examined the effect of sodium fluoride (NaF) on diclofenac (DIC)-induced gastroduodenal and hepatic toxicity in rats. In addition, the potential protective role of Luteolin (Lut), an antioxidant and anti-inflammatory flavonoid, in co-exposure to NaF and DIC was also investigated. Five groups of rats were treated thus: Group A (control): distilled water vehicle for 8 days; Group B: DIC (9 mg/kg) orally, twice daily from days 6 to 8; Group C: NaF (300 ppm) plus DIC for the final 3 days; Groups D and E: Luteolin at 100 mg/kg and 200 mg/kg, respectively, with concurrent NaF and DIC exposures. Rats co-treated with DIC and NaF exhibited the highest severity of dark watery diarrhea and gastroduodenal hemorrhages. NaF aggravated the DIC-induced increases in malondialdehyde (MDA), advanced oxidation protein products (AOPP), protein carbonyls (PC), H₂O₂, and nitric oxide, while inhibiting glutathione peroxidase (GPx) and glutathione S-transferase (GST) in all the tissues. In contrast, Luteolin treatment significantly attenuated the gastroduodenal and hepatic damage caused by NaF and DIC co-administration by suppressing oxidative damage and lesions in the tissues. These results show, for the first time, that NaF may enhance diclofenac-induced gastrointestinal toxicity and also suggest that Luteolin may be a promising lead for the treatment of drug-induced gastroenteropathy.

Pharmacological management of pain after periodontal surgery: a systematic review with meta-analysis

OBJECTIVES

To assess and compare the pharmacological effect of different drugs on pain relief after periodontal surgery.

MATERIALS AND METHODS

Five databases were searched up to September 2019. The eligible studies comprised randomized clinical trials, involving only adult individuals that received any periodontal surgery and presenting two distinct groups of therapeutic regimens to control postoperative pain. Placebo groups could be included. The risk of bias was assessed with the RoB 2 Cochrane tool and the GRADE system. Meta-analyses were performed using different follow-up and drug comparisons.

RESULTS

Overall, 2398 studies were identified, of which 35 were included. Low risk of bias was determined for the majority of the studies. The meta-analyses showed that the comparison of dexamethasone or non-steroidal anti-inflammatory drugs (NSAID) versus placebo favored the use of both interventions in a follow-up of 1 to 8 h for open flap procedures (OFP). However, no statistical difference was found for the comparison between NSAID and dexamethasone for OFP.

CONCLUSIONS

Patients may benefit from several pharmacological schemes for pain relief after periodontal surgeries. However, due to the high heterogeneity among studies, no fixed pharmacological protocol could be proposed.

CLINICAL RELEVANCE

There is not enough evidence to recommend one therapeutic scheme. However, untreated pain is harmful to the patients and it is not advisable.

aQbD as a platform for IVRT method development - A regulatory oriented approach

The EMA draft guideline on quality and equivalence of topical products and the FDA non-binding product specific guidances release has encouraged the establishment of a regulatory background for in vitro release testing (IVRT). Herein, a novel framework applicable to the development of a discriminatory IVRT method is described, according to analytical quality by design (aQbD) principles. A commercially available diclofenac emulgel formulation was used as model product. Through the definition of IVRT analytical target profile, a risk assessment analysis was carried out, in which the critical analytical attributes (in vitro release rate, cumulative amount released at an initial/final point and dose depletion) and critical method variables (medium, membrane and dosage regimen) were identified. Based on this information, a 3 × 2 × 3 full factorial design was performed. Statistical modeling and system desirability assessment enabled the selection of the most suitable IVRT parameters, which were fully validated according with new EMA requirements. These consisted of PBS:Ethanol (80:20, pH = 7.4), Tuffryn membranes and 300 mg of applied product. aQbD provided a comprehensive framework for developing a reliable and effective IVRT method. A thorough analysis of the new EMA draft guideline requirements revealed that some of the established criteria may be challenging to attain.

Single-dose diclofenac in healthy volunteers can cause decrease in renal perfusion measured by functional magnetic resonance imaging

OBJECTIVES

We investigated changes of renal perfusion after topical and oral diclofenac administration in healthy volunteers using functional magnetic resonance imaging (MRI) with arterial spin labelling (ASL).

METHODS

Twenty-four healthy human participants (21-51 years) underwent 1.5T MRI before and 1 h after a single oral dose of diclofenac (50 mg). Twelve of 24 participants underwent an additional MRI examination following 3-day topical diclofenac administration. For renal perfusion imaging, a flow-sensitive alternating inversion-recovery TrueFISP ASL sequence was applied. Plasma concentrations of diclofenac and serum concentrations of thromboxane were determined.

KEY FINDINGS

After oral diclofenac application, large interindividual differences in plasma concentrations were observed (range <3-4604 nm). Topical diclofenac application did not result in relevant systemic diclofenac levels (range 5-75 nm). MRI showed a significant reduction of renal perfusion in individuals with diclofenac levels ≥225 nm (baseline: 347 ± 7 vs diclofenac: 323 ± 8 ml/min/100 g, P < 0.01); no significant differences were observed in participants with diclofenac levels <225 nm. Diclofenac levels correlated negatively with thromboxane B2 levels pointing towards target engagement.

CONCLUSIONS

Single-dose diclofenac caused a decrease in renal perfusion in participants with diclofenac levels ≥225 nm. We demonstrated that even a single dose of diclofenac can impair renal perfusion, which could be detrimental in patients with underlying chronic kidney disease or acute kidney injury.

Diclofenac induced gastrointestinal and renal toxicity is alleviated by thymoquinone treatment

The aim of this study was to investigate whether thymoquinone (TQ) could alleviate diclofenac (DCLF)-induced gastrointestinal and renal toxicity in rats. Diclofenac was administered via intramuscular injection twice daily for 5 days and TQ was given by gavage for the same period. Hematological and biochemical profiles were measured with autoanalyzers while reactive oxygen/nitrogen species (ROS/RNS) generation and total antioxidant capacity (TAC) were assayed by standard kits. Tissue injuries were evaluated by microscopy and histopathological scoring. Diclofenac treatment caused kidney and liver function test abnormalities, reduced hematocrit and hemoglobin levels but increased WBC and platelet counts. Histopathological findings showed renal tubular damage, gastrointestinal lesions and increased fibrosis in DCLF treated rats. Thymoquinone administration, along with DCLF treatment, attenuated hematological test abnormalities and DCLF induced renal functional impairment as evident by significantly restored serum creatinine and blood urea nitrogen levels. Similarly, TQ treatment significantly alleviated liver function test abnormalities and decreased tissue injury in the stomach and duodenum. Diclofenac treatment caused increased ROS/RNS formation and decreased TAC in the kidney, stomach and duodenal tissue. Thymoquinone administration increased gastrointestinal and renal TAC in DCLF treated rats. These results indicate that TQ could ameliorate gastrointestinal and renal toxicity induced by high dose DCLF treatment.