Anti-arthritic Drugs Research Articles

Folate coupled poly(ethyleneglycol) conjugates of anionic poly(amidoamine) dendrimer for inflammatory tissue specific drug delivery

Folate receptor is overexpressed on the activated (but not quiescent) macrophages in both animal models and human patients with naturally occurring rheumatoid arthritis. The aim of this study was to prepare folate targeted poly(ethylene glycol) (PEG) conjugates of anionic dendrimer (G3.5 PAMAM) as targeted drug delivery systems to inflammation and to investigate its biodistribution pattern in arthritic rats. Folate-PEG-PAMAM conjugates, with different degrees of substitution were synthesized by a two-step reaction through a carbodiimide-mediated coupling reaction and loaded with indomethacin. Folate-PEG conjugation increased the drug loading efficiency by 10- to 20-fold and the in vitro release profile indicated controlled release of drug. The plasma pharmacokinetic parameters indicated an increased AUC, circulatory half-life and mean residence time for the folate-PEG conjugates. The tissue distribution studies revealed significantly lesser uptake by stomach for the folate-PEG conjugates, thereby limiting gastric-related side effect. The time-averaged relative drug exposure (r(e)) of the drug in paw for the folate-PEG conjugates ranged from 1.81 to 2.37. The overall drug targeting efficiency (T(e)) was highest for folate-PEG conjugate (3.44) when compared to native dendrimer (1.72). The folate-PEG-PAMAM conjugates are the ideal choice for targeted delivery of antiarthritic drugs to inflammation with reduced side-effects and higher targeting efficiency.

Difference in Preventive Effects Between the Phosphodiesterase IV Inhibitor Rolipram and Anti-Arthritic Drugs on Antigen-Induced Arthritis in Mice

The efficacy of the phosphodiesterase (PDE) IV inhibitor rolipram on antigen-induced arthritis (AIA) in mice was evaluated in comparison with clinically used anti-arthritic drugs. To induce AIA, DBA/1 mice were immunized with ovalbumin (OVA) emulsified with CFA (day 0) followed by intra-articular injection of OVA on day 21. Rolipram and clinically used anti-arthritic drugs including indomethacin (IND), dexamethasone (DEX), methotrexate (MTX), auranofin (AUR), and D-penicillamine (D-PA) were orally administered daily from days 0 to 20. On day 22, anti-OVA IgG in serum, proliferative responses of spleen cells to the OVA, and anti-OVA IgG2a and interferon (IFN)-γ as indicators of Th1 responses, as well as anti-OVA IgG1 and interleukin (IL)-10 as those of Th2 reactions, were measured. Treatment with rolipram was followed by inhibition of the early phase of AIA associated with downregulation of both OVA-specific splenocyte proliferation and decreases of IFN-γ released from the spleen cells but no decreases of the amount of IL-10, or levels of anti-OVA IgG, IgG2a, and IgG1. All clinically used anti-arthritic drugs were more effective in suppressing the late phase of AIA compared with the early phase of joint inflammation. The suppression of AIA by clinically used anti-arthritic drugs was associated with down-regulation of not only Th1 but also Th2 responses. These results suggest that PDE IV inhibitors such as rolipram may exert their suppressive effects on AIA with relatively selective downregulation of antigen-specific Th1 responses compared with anti-arthritic drugs.

Collagen-induced arthritis in C57BL/6 mice is associated with a robust and sustained T-cell response to type II collagen

Many genetically modified mouse strains are now available on a C57BL/6 (H-2b) background, a strain that is relatively resistant to collagen-induced arthritis. To facilitate the molecular understanding of autoimmune arthritis, we characterised the induction of arthritis in C57BL/6 mice and then validated the disease as a relevant pre-clinical model for rheumatoid arthritis.C57BL/6 mice were immunised with type II collagen using different protocols, and arthritis incidence, severity, and response to commonly used anti-arthritic drugs were assessed and compared with DBA/1 mice. We confirmed that C57BL/6 mice are susceptible to arthritis induced by immunisation with chicken type II collagen and develop strong and sustained T-cell responses to type II collagen. Arthritis was milder in C57BL/6 mice than DBA/1 mice and more closely resembled rheumatoid arthritis in its response to therapeutic intervention. Our findings show that C57BL/6 mice are susceptible to collagen-induced arthritis, providing a valuable model for assessing the role of specific genes involved in the induction and/or maintenance of arthritis and for evaluating the efficacy of novel drugs, particularly those targeted at T cells.

The development of folate-PAMAM dendrimer conjugates for targeted delivery of anti-arthritic drugs and their pharmacokinetics and biodistribution in arthritic rats

The aim of this study was to synthesize folate-dendrimer conjugates as suitable vehicle for site specific delivery of anti-arthritic drug (indomethacin) to inflammatory regions and to determine its targeting efficiency, biodistribution in adjuvant induced arthritic rats. Folic acid was coupled to the surface amino groups of G4-PAMAM dendrimer (G4D) via a carbodiimide reaction and loaded with indomethacin. The conjugates were characterized by (1)H-NMR and IR spectroscopy. The drug content and percent encapsulation efficiency increased with increasing folate content for the dendrimer conjugates. The in vitro release rate was decreased for the folate conjugates when compared with unconjugated dendrimer (DNI). The plasma concentration profile showed a biphasic curve indicating rapid distribution followed by slow elimination. The AUC(0-infinity), half-life and residence time of indomethacin in inflamed paw was higher for folate-dendrimer conjugates. The time-averaged relative drug exposure (r(e)) of the drug in paw and overall drug targeting efficiency (T(e)) were higher for folate conjugate with 21 folate moieties (4.1 and 2.78, respectively) when compared with DNI (1.91 and 1.88, respectively). This study demonstrated the superiority of active targeting over dendrimer mediated passive targeting and also for the first time, folate-mediated targeting of an anti-arthritic drug to the inflammatory tissues.

Arthritic disease suppression and cartilage protection with glycosaminoglycan polypeptide complexes (Peptacans) derived from the cartilage extracellular matrix: a novel approach to therapy

Molecular fragments of cartilage are antigenic and can stimulate an autoimmune response. Oral administration of type II collagen prevents disease onset in animal models of arthritis but the effects of other matrix components have not been reported. We evaluated glycosaminoglycan polypeptides (GAG-P) and matrix proteins (CaP) from cartilage for a) mitigating disease activity in rats with collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) and b) stimulating proteoglycan (PG) synthesis by chondrocytes in-vitro. CIA and AIA were established in Wistar rats using standard methods. Agents were administered orally (10-200 mg/kg), either for seven days prior to disease induction (toleragenic protocol), or continuously for 15 days after injecting the arthritigen (prophylactic protocol). Joint swelling and arthritis scores were determined on day 15. Histological sections of joint tissues were assessed post-necropsy. In chondrocyte cultures, CaP + / - interleukin-1 stimulated PG biosynthesis. CaP was also active in preventing arthritis onset at 3.3, 10 or 20 mg/kg in the rat CIA model using the toleragenic protocol. It was only active at 20 and 200 mg/kg in the CIA prophylactic protocol. GAG-P was active in the CIA toleragenic protocol at 20 mg/kg but chondroitin sulfate and glucosamine hydrochloride or glucosamine sulfate were all inactive. The efficacy of CaP in the rat AIA model was less than in the CIA model. These findings lead us to suggest that oral CaP could be used as a disease-modifying anti-arthritic drug.

A mass spectrometric investigation of the binding of gold antiarthritic agents and the metabolite [Au(CN)2]− to human serum albumin

Electrospray ionisation (ESI) mass spectrometry was used to examine the reactions of the clinically used antiarthritic agent [Au(S2O3)2]3-, and AuPEt3Cl, a derivative of another clinically used agent auranofin, with human serum albumin (HSA) obtained from a human volunteer. Both compounds reacted readily with HSA to form complexes containing one or more covalently attached gold fragments. In the case of AuPEt3Cl, binding was accompanied by the loss of the chloride ligand, while for [Au(S2O3)2]3- the mass spectral data indicated binding of Au(S2O3) groups. Experiments performed using HSA with Cys34 blocked by reaction with iodoacetamide were consistent with reaction of both gold compounds with this amino acid. Separate blocking experiments using diethylpyrocarbonate and AuPEt3Cl also provided evidence for histidine residues acting as lower-affinity binding sites for this gold compound. ESI mass spectra of solutions containing [Au(S2O3)2]3- or [Au(CN)2]-, and HSA, provided evidence for the formation of protein complexes in which intact gold molecules were non-covalently bound. In the case of [Au(S2O3)2]3-, these non-covalent complexes proved to be transitory in nature. However, for [Au(CN)2]- a non-covalent complex containing a single gold molecule bound to HSA was found to be stable, and constituted the main adduct formed in solutions containing low-to-medium Au-to-HSA ratios. Evidence was also obtained for the formation of a covalent adduct in which a single Au(CN) moiety was bonded to Cys34 of the protein. AuPEt3Cl reacted to a much lower extent with HSA that had Cys34 modified by formation of a disulfide bond to added cysteine, than with unmodified HSA. This suggests that the extent of modification of the protein in vivo may have an important influence on the transport and bioavailability of gold antiarthritic drugs.

Dispute over Vioxx study plays out in New England journal

The New England Journal of Medicine is maintaining that a Canadian-led study of the anti-arthritis drug rofecoxib (Vioxx) that it published in November 2000 contained “misleading” conclusions regarding the drug's safety. But the authors of the Vioxx Gastrointestinal Outcomes Research (VIGOR)

Establishment of a cell-based drug screening system for identifying selective down-regulators of mPGES-1

To establish a drug screening system based on transcriptional regulation of microsomal PGE(2) synthase 1 (mPGES-1), cyclooxygenase 1 (COX-1) and 2 (COX-2) for discovering selective down-regulators of mPGES-1. The upstream regulatory sequences of mPGES-1, COX-1, COX-2 were respectively cloned into pGL3B-neo vector containing luciferase gene and neomycin resistance gene (the pGL3B-neo vector had been previously constructed by cloning the neomycin resistance gene into the Sal I site of the pGL3-Basic vector). After that, the recombinant reporter gene vectors pGL3B-neo/mPGES-1, pGL3B-neo/COX-1, pGL3B-neo/COX-2 were respectively transfected into A549 cells and therefore stable cell lines, namely M 1, M 2 and M 3, were obtained. Samples were detected then by testing luciferase activity of M 1, M 2 and M 3 cells in microtiter wells to identify compounds that can selectively down-regulate mPGES-1 expression. Through luciferase activity testing, the compounds which had more than 40 % inhibition ratio on M 1 and less than 20 % inhibition ratio on M 2 and M 3 cells could be regarded as hits. Using the cell-based reporter gene assay, we screened compounds for selectively down-regulation of mPGES-1 expression and several compounds were discovered. A cell-based drug screening system was established to screen selective down-regulators of mPGES-1 expression, and compound CM188 was identified, which might become a lead compound for novel anti-arthritic drugs.

A comparative study on the efficacy of rofecoxib in monoarticular arthritis induced by latex of Calotropis procera and Freund’s complete adjuvant

The role of prostaglandins in Calotropis procera latex induced inflammation and hyperalgesia has been well established. The acute inflammation induced by the dried latex (DL) of this plant could be effectively ameliorated by standard anti-inflammatory drugs. In present study we have evaluated the efficacy of rofecoxib, a COX-2 inhibitor in monoarthritis induced by intra-articular injection of DL and compared it with that against Freund's Complete Adjuvant (FCA). DL and FCA were injected into the right ankle joint of the rat and the joint diameter was measured by a micrometer screw gauge on day 0, 4, 8, 12, 20 and 28. Concomitantly the hyperalgesic response was also evaluated by motility test, stair climbing ability test, dorsal flexion pain test and compression test. The effect of rofecoxib was evaluated on these parameters in both the models. Both DL and FCA produced peak inflammation on day 4 that was associated with decreased pain threshold and functional impairment. Although rofecoxib was more effective in improving motility in the DL model, its effect on joint inflammation, hyperalgesia and stair climbing ability was comparable in both the models. Thus, our study indicates that DL induced monoarthritis could be used as a model for the screening and evaluation of anti-inflammatory and anti-arthritic drugs.

Suppressive Effects of JCICM-6, the Extract of an Anti-arthritic Herbal Formula, on the Experimental Inflammatory and Nociceptive Models in Rodents

JCICM-6, the extract of an anti-arthritic herbal formula composed of medicinal herbs of Sinomenium acutum, Aconitum carmichaeli DEBX., Curcuma Longa L., Paeonia lactiflora PALL., and Paeonia suffruticosa ANDR., was examined in the effectiveness and mechanism in reducing experimentally-induced inflammation and nociception using nine animal models. JCICM-6 was extracted from herbs and purified with Amberlite XAD-7HP adsorbent resin and analyzed with HPLC-fingerprint for quality consistency. In acute inflammatory models, the paw edema of rats was induced by subcutaneous injection of carrageenan or pro-inflammatory mediators, including histamine, serotonin, bradykinin, and prostaglandin E(2) (PGE(2)) into the right hind paws of animals; while the ear edema of mice was induced by applying arachidonic acid or 12-O-tetradecanoylphorbol 13-acetate (TPA) on the ear surface. In nociceptive models, the tail-flick response induced by radiant heat stimulation was measured and the numbers of abdominal writhing episodes of mice induced by intraperitoneal injection of acetic acid were recorded. JCICM-6 orally administered in a range of dosages from 0.438 g to 1.75 g/kg significantly and dose-dependently suppressed the paw edema of rats induced by carrageenan or various pro-inflammatory mediators and the ear edema of mice induced by arachidonic acid or TPA. JCICM-6 also significantly prolonged the reaction time of rats to radiant heat stimulation and reduced the numbers of writhing episodes of mice. These results indicated that JCICM-6 possesses significant anti-inflammatory and analgesic effects, which implies that it would be a potential candidate for further investigation as a new anti-arthritic botanical drug for humans.

Drug delivery strategies for cathepsin inhibitors in joint diseases

Cathepsins play important roles in the development of joint and bone diseases such as osteoporosis, rheumatoid arthritis (RA) and osteoarthritis (OA). Cathepsin inhibitors are presently in development and clinical testing for use as novel disease-modifying drugs for the improved treatment of osteoporosis. They may also be applicable for the treatment of joint diseases. However, some barriers still hamper their clinical applications in these indications. Based on pathophysiological features of RA and OA, the authors discuss six potential drug delivery strategies for the effective delivery of cathepsin inhibitors or other antiarthritic drugs to the arthritic joint tissue. Successful application of these strategies may significantly contribute to a more effective and safe treatment of RA and OA.

Mononuclear metal complexes with Piroxicam: Synthesis, structure and biological activity

Piroxicam (=H pir) is a non-steroidal anti-inflammatory and an anti-arthritic drug. VO 2+, Mn 2+, Fe 3+, MoO 2 2 + and UO 2 2 + complexes with deprotonated piroxicam have been prepared and characterized with the use of infrared, UV–Vis, nuclear magnetic resonance and electron paramagnetic resonance spectroscopies. The experimental data suggest that piroxicam acts as a deprotonated bidentate ligand in all complexes and is coordinated to the metal ion through the pyridine nitrogen and the amide oxygen. Molecular mechanics calculations in the gas state have been performed in order to propose a model for the Fe 3+, VO 2+ and MoO 2 2 + complexes. Potential anticancer cytostatic and cytotoxic effects of piroxicam complexes with VO 2+, Mn 2+ and MoO 2 2 + on human promyelocytic leukemia HL-60 cells have been investigated. Among all complexes, only VO( pir) 2(H 2O) clearly induces apoptosis after 24-h incubation, whereas piroxicam induces apoptosis after 57-h incubation.

Solution and solid state NMR studies of some selenium analogues of auranofin (an anti-arthritic gold drug)

Three mixed ligand complexes of gold(I) with phosphines and selenones, [Et3PAuSe=C<]Br as analogues of auranofin (Et3PAuSR) have been prepared and characterized by elemental analysis, IR and NMR methods. A decrease in the IR frequency of the C=Se mode of selenones upon complexation is indicative of selenone binding to gold(I) via a selenone group. An upfield shift in 13C NMR for the C=Se resonance of the selenones and downfield shifts in 31P NMR for the R3P moiety are consistent with the selenium coordination to gold(I). 13C solid state NMR shows the chemical shift difference between free and bound selenone to gold(I) for ImSe and DiazSe to be ca 10 and 17 ppm respectively. Large 77Se NMR chemical shifts (55 ppm) upon complexation in the solid state for [Et3PAuDiazSe]Br compared to [Et3PAuImSe]Br (10 ppm) indicates the former to be more stable and the Au–Se bond to be stronger than in the latter complex.

A Tail of Hearing Service: Service Dogs Can Fill Gaps for People With Hearing Loss

A Tail of Hearing Service: Service Dogs Can Fill Gaps for People With Hearing Loss

Pharmacokinetic interaction and erythromycin-induced sudden cardiac death: Implications for practice

The observational science of pharmacovigilance has been brought to the consciousness of the clinician in the wake of the recent withdrawal of Merck’s anti-arthritis drug rofecoxib (Vioxx) and as the role of the Food and Drug Administration (FDA) in providing guidance on drug safety issues has come increasingly under scrutiny.

Albumin microspheres as carriers for the antiarthritic drug celecoxib

The present study investigates the preparation of celecoxib-loaded albumin microspheres and the biodistribution of technetium-99m ((99m)Tc)-labeled celecoxib as well as its microspheres after intravenous administration. Microspheres were prepared using a natural polymer BSA using emulsification chemical cross-linking method. The prepared microspheres were characterized for entrapment efficiency, particle size, and in vitro drug release. Surface morphology was studied by scanning electron microscopy. Biodistribution studies were performed by radiolabeling celecoxib (CS) and its microspheres (CMS) using (99m)Tc and injecting arthritic rats intravenously. The geometric mean diameter of the microspheres was found to be 5.46 microm. In vitro release studies indicated that the microspheres sustained the release of the drug for 6 days. Radioactivity measured in different organs after intravenous administration of celecoxib solution showed a significant amount of radioactivity in the liver and spleen. In case of celecoxib-loaded microspheres, a significant amount of radioactivity accumulated in the lungs. No significant difference (P > .1) in the radioactivity was observed between the inflamed joint and the noninflamed joint following intravenous injection of (99m)Tc-CS. However, in case of the microspheres (CMS), the radioactivity present in the inflamed joint was 2.5-fold higher than in the noninflamed joint. The blood kinetic studies revealed that celecoxib-loaded albumin microspheres exhibited prolonged circulation than the celecoxib solution.

Effect of Varying Types of Anti-Arthritic Drugs on TH1 and TH2 Immune Responses in Mice

The present study was undertaken to study the effect of varying types of anti-arthritic drugs on Th1 and Th2 immune responses in mice. To immunize mice, ovalbumin (OVA) emulsified with complete Freund's adjuvant was injected s.c. at the base of the tail (day 0). Indomethacin (IND) as a non-steroidal antiinflammatory drug (NSAID), dexamethasone (DEX) as a steroidal antiinflammatory drug, methotrexate (MTX), auranofin (AUR), and D-penicillamine (D-PA) as an anti-rheumatic drugs were orally administrated daily from days 0 to 20. On day 21, anti-OVA IgG2a and interferon (IFN)-gamma as indicators of Th1 responses and anti-OVA IgG1 and interleukin (IL)-10 as those of Th2 responses were measured. Treatments with IND, DEX, MTX and AUR were followed by decreases in OVA-specific IgG and proliferation of spleen cells to the antigen. Treatments with IND, DEX, MTX and AUR inhibited both Th1 and Th2 immune responses, although the inhibitory effects of these drugs on the antigen-specific IgG2a and IFN-gamma production appeared to be greater than those on IgG1 and IL-10 production. D-PA failed to influence anti-OVA IgG, IgG2a and IgG1 production as well as IFN-gamma and IL-10 secretion. Administrations of all the drugs used resulted in suppression of antigen (OVA)-induced arthritis in mice which was associated with inhibition of anti-OVA IgG2a but not IgG1 production. These results suggest that anti-arthritic drugs including IND, DEX, MTX and AUR appear to suppress Th1 and, to a lesser extent, Th2 immune responses, and their anti-inflammatory effects on human rheumatoid arthritis might be at least in part explained by downregulation by these drugs of Th1 responses involved in the disease.

Lawsuits mount in wake of rofecoxib (Vioxx) withdrawal

Within 2 weeks of Merck & Co.'s decision to withdraw the anti-arthritis drug rofecoxib (Vioxx) because of its cardiovascular risks, lawyers filed 10 class-action lawsuits collectively representing several thousand plaintiffs in Canada against the firm and its Canadian subsidiary, Merck Frosst Canada

Albumin-coupled methotrexate (MTX-HSA) is a new anti-arthritic drug which acts synergistically to MTX.

To evaluate the anti-arthritic effects of the new inflammation-targeted drug MTX-HSA and to investigate whether peripheral blood mononuclear cells (PBMC) are potential target cells for albumin-mediated drug delivery. The murine model of collagen-induced arthritis (CIA) was used to measure the anti-arthritic effect of MTX, MTX-HSA or a combination of both (n = 30 to 35 per group). In addition, the uptake of fluorescence-labelled albumin (AFLc-HSA) in PBMC of 14 patients with RA was measured by fluorescence-activated cell sorting (FACS). In equivalent doses of 7.5 mg/kg intravenously (IV) twice a week, MTX-HSA is significantly (P<0.02) superior to MTX in inhibiting the development of CIA and reducing the joint count as well as the number of affected paws. When given in lower doses as combination therapy, both drugs act synergistically (P<0.03). A mean of 96, 72 and 64% of the CD14-, CD16- and CD20-positive cells from peripheral blood of rheumatoid arthritis (RA) patients showed an uptake of albumin after incubation with AFLc-HSA in vitro. This finding was not significantly different in comparison to healthy controls. In contrast, the number of CD3-positive cells taking up albumin is increased significantly in RA patients in comparison to controls (26.3 +/- 12.9% s.d. vs 11.6 +/- 7.3% s.d.; P = 0.005). The data show that the effectiveness of MTX-HSA in CIA is superior to MTX and that both drugs act synergistically. In addition, albumin appears to be taken up by peripheral blood cells, suggesting that they might be one of the potential target cells of this novel anti-arthritic treatment approach.

Direct observation of covalent adducts with Cys34 of human serum albumin using mass spectrometry

The interactions of the unpaired thiol residue (Cys34) of human serum albumin (HSA) with low-molecular-weight thiols and an Au(I)-based antiarthritic drug have been examined using electrospray ionization mass spectrometry. Early measurements of the amount of HSA containing Cys34 as the free thiol suggested that up to 30% of circulating HSA bound cysteine as a mixed disulfide. It has also been suggested that reaction of HSA with cysteine, occurs only on handling and storage of plasma. In our experiments, there were three components of HSA in freshly collected plasma from normal volunteers, HSA, HSA + cysteine, and HSA + glucose in the ratio ∼50:25:25. We addressed this controversy by using iodoacetamide to block the free thiol of HSA in fresh plasma, preventing its reaction with plasma cysteine. When iodoacetamide was injected into a vacutaner tube as blood was collected, the HSA was modified by iodoacetamide, with 20–30% present as the mixed disulfide with cysteine (HSA + cys). These data provide strong evidence that 20–30% of HSA in normal plasma contains one bound cysteine. Reaction of HSA with [Au(S 2O 3) 2] 3− resulted in formation of the adducts HSA + Au(S 2O 3) and HSA + Au. Reaction of HSA with iodoacetamide prior to treatment with [Au(S 2O 3) 2] 3− blocked the formation of gold adducts.