Targeting methionyl tRNA synthetase: design, synthesis and antibacterial activity against Clostridium difficile of novel 3-biaryl-N-benzylpropan-1-amine derivatives

The synthesis of a series of benzimidazole-N-benzylpropan-1-amines and adenine-N-benzylpropan-1-amines is described. Subsequent evaluation against two strains of the anaerobic bacterium Clostridium difficile was performed with three amine derivatives displaying MIC values of 16 μg/mL. Molecular docking studies of the described amines determined that the amines interact within two active site pockets of C. difficile methionyl tRNA synthetase with methoxy substituents in the benzyl ring and an adenine biaryl moiety resulting in optimal binding interactions.

Anti-tumour necrosis factor treatment increases circulating T helper type 17 cells similarly in different types of inflammatory arthritis

We investigated changes in circulating T helper type 17 (Th17) cells following anti-tumour necrosis factor (TNF) in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) patients. Peripheral blood mononuclear cells (PBMC) were isolated from 25 RA, 15 AS and eight PsA patients at baseline 4 and 12 weeks after treatment, and Th17 cell frequencies were analysed using interleukin (IL)-17 enzyme-linked immunospot (ELISPOT) and flow cytometry. A significant increase in IL-17-producing cells was observed by ELISPOT in RA and AS patients at 12 weeks. Flow cytometry confirmed significant increases in CD4(+) IL-17(+) cells at 12 weeks in RA and AS and 4 weeks in PsA patients. Anti-TNF treatment increases circulating Th17 cells in three different diseases.

Blockade of tumour necrosis factor-α in experimental autoimmune encephalomyelitis reveals differential effects on the antigen-specific immune response and central nervous system histopathology

In various autoimmune diseases, anti-tumour necrosis factor (TNF)-α treatment has been shown to reduce both clinical disease severity and T helper type 1 (Th1)1/Th17 responses. In experimental autoimmune encephalomyelitis (EAE), however, the role of TNF-α has remained unclear. Here, C57BL/6 mice were immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 and treated with anti-TNF-α, control antibody or vehicle. The clinical disease course, incidence and severity were assessed. On day 20 after immunization the antigen-specific Th1/Th17 response was evaluated by enzyme-linked immunospot (ELISPOT) in spleen and central nervous system (CNS). Also, the extent of spinal cord histopathology was analysed on semi- and ultrathin sections. Our results demonstrate that anti-TNF-α treatment reduced the incidence and delayed the onset of EAE, but had no effect on disease severity once EAE had been established. Whereas anti-TNF-α treatment induced an increase in splenic Th1/Th17 responses, there was no effect on the number of antigen-specific Th1/Th17 cells in the spinal cord. Accordingly, the degree of CNS histopathology was comparable in control and anti-TNF-α-treated mice. In conclusion, while the anti-TNF-α treatment had neither immunosuppressive effects on the Th1/Th17 response in the CNS nor histoprotective properties in EAE, it enhanced the myelin-specific T cell response in the immune periphery.

Amorphous solid dispersions and nano-crystal technologies for poorly water-soluble drug delivery

Poor water-solubility is a common characteristic of drug candidates in pharmaceutical development pipelines today. Various processes have been developed to increase the solubility, dissolution rate and bioavailability of these active ingredients belonging to BCS II and IV classifications. Over the last decade, nano-crystal delivery forms and amorphous solid dispersions have become well established in commercially available products and industry literature. This article is a comparative analysis of these two methodologies primarily for orally delivered medicaments. The thermodynamic and kinetic theories relative to these technologies are presented along with marketed product evaluations and a survey of commercial relevant scientific literature.

What have we learnt from targeted anti-TNF therapy?

Anti-tumour necrosis factor (anti-TNF) therapy of patients with rheumatoid arthritis dates back to 1992, when the first proof-of-principle trials were performed in London by Maini and Feldmann. Considerable studies of the mechanism of action were performed, and insights into the way in which anti-TNF therapy delivers its benefit were obtained. In this brief review, certain aspects of knowledge acquired and the many gaps will be reviewed. Focus will be on the TNF-dependent cytokine cascade and what it means, and potential new approaches to treatment. Finally, an entertaining challenge: might many or even all unmet clinical needs be dealt with through cytokine analysis?

Preformulation Studies on Freund's Incomplete Adjuvant Emulsion

Freund's Incomplete Adjuvant (FIA), which is used in vaccine therapy, is a water-in-oil emulsion delivery system consisting of an aqueous internal phase containing an antigenic protein dispersed in an external phase containing a mixture of mannide monooleate and light mineral oil. Preformulation studies are reported in this investigation for FIA emulsion. The preformulation studies included the determination of the critical micelle concentration (CMC) of the formulations investigated, the surface activity of mannide monooleate at the interface between the oil phase and the aqueous phase containing ovalbumin as the model antigenic protein, and the effect of ovalbumin on the surface activity at the interface. The influence of the concentration of mannide monooleate and/or ovalbumin on the interfacial tension between light mineral oil and either purified water or 0.9% w/v normal saline solution was measured by the DuNouy Ring Method at 25 degrees C. The CMC was determined experimentally from the relationship between the concentration of the surface active agent in each formulation and the interfacial tension. The number of moles of the surface active agent per unit area at the interface (surface excess concentration) was calculated from the Gibbs' Adsorption equation. The results indicated that mannide monooleate was an effective surface active agent since the formulation containing only mannide monooleate provided the lowest magnitude of CMC. The presence of the surface active agent, mannide monooleate and/or ovalbumin, in the formulations studied reduced the interfacial tension between the two phases. The surface activity was influenced by the presence of an electrolyte (sodium chloride), a protein (ovalbumin), or mannide monooleate in the formulation. The presence of antigenic proteins in the aqueous phase of a waterin-oil emulsion influenced the effectiveness of a surface active agent in the formulation.

Pathogenesis and therapy of rheumatoid arthritis

Rheumatoid arthritis is a chronic disabling disease affecting at least 1% of the population on a worldwide basis. Research aimed at understanding the pathogenesis of this disease led to the identification of TNFalpha as a major pro-inflammatory cytokine expressed in the inflamed joints of patients with rheumatoid arthritis. Subsequently, in vitro studies provided evidence to suggest that TNFalpha played an important role in driving the expression of additional pro-inflammatory cytokines, such as IL-1, GM-CSF, IL-6, and IL-8, in synovial cell cultures. Another important finding that confirmed the pathological significance of TNFalpha was that mice genetically engineered to overexpress TNFalpha spontaneously developed arthritis. Subsequently, the therapeutic effect TNFalpha blockade was tested in animal models prior to clinical trials in human patients, which provided unequivocal verification of the validity of TNFalpha as a therapeutic target. Anti-TNFalpha therapy is now accepted as a fully-validated treatment modality for rheumatoid arthritis.

The anti-allergic drug, N-(3',4'-dimethoxycinnamonyl) anthranilic acid, exhibits potent anti-inflammatory and analgesic properties in arthritis

OBJECTIVES

The degradation of tryptophan by indoleamine 2,3-dioxygenase yields a number of immunomodulatory metabolites, including 3-hydroxyanthranilic acid, 3-hydroxykynurenic acid and quinolinic acid. N-(3',4'-dimethoxycinnamonyl) anthranilic acid (3,4-DAA) is a synthetic anthranilic acid derivative that has been used therapeutically in Japan for many years as an anti-allergic drug and has recently been shown to be effective in a murine model of multiple sclerosis.

METHODS

In the present study, we tested the efficacy of 3,4-DAA in collagen-induced arthritis, a mouse model of rheumatoid arthritis, and analysed its mechanism of action.

RESULTS

Administration of 3,4-DAA after arthritis onset reduced clinical and histological severity of arthritis and reduced pain. It completely abrogated thermal and mechanical hyperalgesia. 3,4-DAA also suppressed Th1 cell activity in lymph node cell cultures and raised serum levels of IL-10. In vitro, 3,4-DAA suppressed IFNgamma production and proliferation of both T and B lymphocytes in a manner comparable with the endogenous tryptophan metabolite, 3-hydroxyanthranilic acid, suggesting similar mechanisms of action.

CONCLUSION

It is concluded that 3,4-DAA has both anti-inflammatory and analgesic properties, and may therefore be useful in filling an unmet need, in the treatment of rheumatoid and other forms of arthritis, especially in the light of its analgesic properties.

Remission of collagen-induced arthritis is associated with high levels of transforming growth factor-beta expression in the joint

Immunization of genetically susceptible strains of mice with heterologous type II collagen leads to the induction of a self-limiting polyarthritis that begins to subside around 10 days after onset of clinical disease. The aims of this study were to compare pro- and anti-inflammatory cytokine expression in the joints during the course of arthritis in order to identify cytokines involved in spontaneous remission of arthritis. DBA/1 mice were immunized with type II collagen and an immunohistochemical analysis of expression of proinflammatory cytokines [tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6] and anti-inflammatory cytokines [IL-10, IL-1ra, transforming growth factor (TGF)-beta1, TGF-beta2 and TGF-beta3] in joints was carried out over the course of the disease. Both pro- and anti-inflammatory cytokines were found to be expressed in early arthritis. However, around 10 days after onset of arthritis, the level of expression of proinflammatory cytokines declined while the level of expression of anti-inflammatory cytokines, particularly TGF-beta1 and TGF-beta2, increased. Surprisingly, TNF-alpha continued to be expressed at low levels during the period of disease remission (30 days after onset). Blockade of TNF-alpha during the period of disease remission had no effect on TGF-beta expression. This study confirms that the level of inflammation in arthritis correlates strongly with the balance of pro- and anti-inflammatory cytokine expression in the joints. Of the anti-inflammatory cytokines studied, TGF-beta1 and TGF-beta2 predominate during the time of disease remission, suggesting that these cytokines are involved in regulating disease activity.

Inflammation is preceded by tumor necrosis factor-dependent infiltration of mesenchymal cells in experimental arthritis

OBJECTIVE

To determine the involvement of mesenchymal progenitor cells in the induction of collagen-induced arthritis (CIA).

METHODS

DBA/1 mice were immunized with type II collagen in adjuvant or adjuvant alone, and the presence of mesenchymal cells in the joints of prearthritic mice was studied by immunohistochemistry.

RESULTS

An analysis of the joints on day 10 postimmunization (at least 10 days before the onset of arthritis) revealed synovial hyperplasia without leukocytic infiltration. Large, round cells expressing bone morphogenetic protein receptors (BMPRs), which serve as markers for primitive mesenchymal cells, were present in increased numbers in the bone marrow adjacent to the joint, in the synovium itself, and within enlarged bone canals that connect the bone marrow to the synovium. Similar changes were observed in mice given adjuvant without collagen. Adjuvant-induced infiltration of BMPR(+) cells and enlargement of bone canals were abrogated by anti-tumor necrosis factor (anti-TNF) treatment and were absent in TNFR p55/p75(-/-) mice. Increased numbers of bone marrow cells and enlarged bone canals were observed in nonimmunized TNF transgenic mice (which spontaneously develop arthritis).

CONCLUSION

These findings suggest that in CIA, there is an antigen-independent (innate) prearthritic phase that prepares the joint for the subsequent immune-mediated arthritis. The induction phase involves marrow-derived mesenchymal cells and requires the presence of TNF.

Solution-based particle formation of pharmaceutical powders by supercritical or compressed fluid CO2 and cryogenic spray-freezing technologies

Micronization is an important procedure used in the pharmaceutical industry to reduce the particle size of active pharmaceutical ingredients (APIs). The spray-drying and milling techniques presently used to micronize drug substances cannot be used to process thermolabile or physically unstable drug substances. Therefore, new micronization techniques, including particle precipitation with supercritical or compressed fluid CO2 and spray-freezing of drug solutions and suspensions into cryogenic gas to produce solid frozen microparticles, are currently being perfected for future use in the pharmaceutical industry. This review highlights the compressed gas and cryogenic liquid technologies being developed as potential solution-based particle formation technologies for drugs that cannot be processed by conventional micronization techniques.

The influence of plasticizer on heat-humidity curing of cellulose acetate phthalate coated beads

The objectives of the present study are to investigate the effect of plasticizer type and level on the curing of cellulose acetate phthalate (CAP) coated beads with and without the presence of humidity. Theophylline beads were coated in a fluidized-bed with CAP dispersion (Aquacoat CPD) plasticized by a water-insoluble plasticizer, diethyl phthalate (DEP), or a water-soluble plasticizer, triethyl citrate (TEC), at various levels. The coated heads were cured at a heat-only condition (50 degrees C for 24 hr) and a heat-humidity condition (50 degrees C/75% RH for 24 hr). Rapid drug release in the acidic media was found for both heat-only and heat-humidity cured beads when plasticizer was not used in the coating dispersion, indicating that the heat-humidity curing is ineffective without the presence of plasticizers. When plasticizer was incorporated in the coating formulations, heat-humidity curing effectively improved the acid resistance of the coated films at all plasticizer levels investigated. The minimum plasticizer level required to obtain enteric release profiles for heat-humidity cured beads coated at an outlet coating temperature of 46 degrees C was 15%. This limit was further decreased when the beads were coated at a lower temperature due to a less plasticizer loss at the lower coating temperature. Between the two plasticizers, less TEC was lost during the coating process, and TEC was more effective compared to DEP with regards to heat-humidity curing at the 10% plasticizer level. The enteric release profiles were reproducible following a 7-day drying period at 40 degrees C for all heat-humidity cured beads that had initially passed the enteric release dissolution test. The rapid leaching of TEC and DEP into the.

Immunotherapy for rheumatoid arthritis

Recently published studies confirm that the long-term use of biological agents targeting TNF-alpha in therapy for rheumatoid arthritis (RA) gives rise to sustained improvement in symptoms and signs of disease, and in the quality of life. Furthermore, it has emerged that anti-TNF therapy protects joints from structural damage, which unexpectedly is also observed in the patient population showing no apparent benefit in control of signs and symptoms. Therapeutic benefit is observed in established disease that is unresponsive to conventional DMARDS and in early DMARDS-naïve RA patients. Thus, for patients with RA, anti-TNF therapies set a new standard for symptom control and joint protection.

Method to recover a lipophilic drug from hydroxypropyl methylcellulose matrix tablets

A reverse-phase high-performance liquid chromatographic (HPLC) method for recovery of the lipophilic drug, alprazolam, from matrix tablets containing the hydrophilic polymer hydroxypropyl methylcellulose (HPMC) was developed. Lipophilic drugs, such as alprazolam, are difficult to completely extract and quantitate from tablets containing HPMC polymer. The percentage of recoveries of alprazolam from placebo powder spiked with alprazolam stock solution and from placebo powder mixed with alprazolam powder were about 100% and 85% to 95%, respectively. The validated method using water to completely dissolve HPMC before the addition of a strong solvent to dissolve and extract the drug from the HPMC solution was shown to be the most reproducible method. Different molecular weight distributions of the HPMC polymer, such as HPMC-K4M and HPMC-K100LV, did not influence the dissolution results of alprazolam using this validated method. Similarly, the excipients composing the matrix tablet formulations, such as dicalcium phosphate dihydrate, dicalcium phosphate anhydrous, calcium sulfate dihydrate, sucrose, dextrose, and lactose monohydrate, did not influence the percent recovery of alprazolam. The recovery method reported herein was shown to be the most efficient to achieve complete recovery of alprazolam from powder blends and tablets containing a variety of excipients and different grades of HPMC.

Chronic relapsing homologous collagen-induced arthritis in DBA/1 mice as a model for testing disease-modifying and remission-inducing therapies

OBJECTIVE

To test whether the chronic relapsing arthritis induced by immunizing DBA/1 mice with homologous type II collagen is a valuable model for testing disease-modifying antiarthritic drugs.

METHODS

Six-week-old male DBA/1 mice were immunized with murine type II collagen in Freund's complete adjuvant, resulting in a chronic relapsing polyarthritis in >80% of the mice 4 weeks after immunization. At the onset of clinical arthritis, mice were treated for 4 weeks with different treatments, including anti-tumor necrosis factor (anti-TNF) and antiinterleukin-12 (anti-IL-12) antibodies, salbutamol, or indomethacin. Alternatively, treatment was administered as a pulse at the beginning of clinical arthritis. Pulse treatments tested included anti-CD3 in combination with anti-TNF, anti-TNF alone, and anti-CD4, either alone or in combination with anti-TNF. After 4 weeks of arthritis, mice were killed and hind paws were assessed histologically for joint damage.

RESULTS

Anti-TNF and salbutamol both suppressed clinical arthritis more effectively than indomethacin and, moreover, protected the joints from damage, whereas indomethacin did not. Anti-IL-12 treatment initiated after the onset of clinical symptoms accelerated disease. Pulse therapy with anti-CD3 plus anti-TNF was found to induce remission, clinically as well as histologically, whereas a pulse with either anti-CD4, anti-TNF, or the combination of anti-CD4 plus anti-TNF was less effective.

CONCLUSION

Chronic relapsing homologous collagen-induced arthritis is a valuable model for identifying remission-inducing antiarthritic drugs and has predictive value with respect to their joint-protective potency.

Investigation of some commercially available spacer devices for the delivery of glucocorticoid steroids from a pMDI

Five commercially available spacers were investigated to determine their influence on the percentage of drug retained in the spacer device, percentage fine particle fraction (FPF), percentage deposited in the induction port, mass median aerodynamic diameter (MMAD), and geometric standard deviation (GSD). Betamethasone valerate (BMV) and triamcinolone acetonide (TAA) were used as model drugs in the pressurized metered dose inhaler (pMDI) formulations containing the propellant HFA 134a. The BMV was dissolved in an ethanol/HFA 134a system, and the TAA was suspended in HFA 134a using ethanol as a dispersing agent. The metering chamber volume of the valve was either 50 microl or 150 microl. The spacer devices investigated included the ACE, Aerochamber, Azmacort, Easivent, and Ellipse spacers. Each spacer device was attached to an Andersen Cascade Impactor powered by a vacuum pump. Cascade impaction data were used to derive the percentage drug deposited in the induction port, MMAD, GSD, and FPF. The BMV particles emitted from the spacers were finer than the TAA particles because the dissolved drug precipitated as the cosolvent evaporated. The TAA particles had significantly larger MMADs because many undissolved drug particles were contained within each droplet following actuation. After evaporation of the liquid continuous phase, the suspended drug aggregated to form larger agglomerates than those particles precipitated from the BMV pMDI solution droplets. The addition of a spacer device lowered the MMAD to less than 4.7 microm for particles from both the BMV pMDI solution and the TAA pMDI suspension. The addition of a spacer device also lowered the percentage drug deposited in the induction port. The FPF was significantly increased when a spacer device was used. The MMAD significantly decreased when a spacer device was added for the two model drugs when using the 150-microl metering valves, but the difference was not statistically significant when the 50-microl valves were used (P < .05). The GSD was not influenced by the use of a spacer device. The use of a spacer device will enhance pMDI therapy by reducing the amount of drug deposited in the oropharyngeal region, which will lead to fewer instances of local and systemic side effects. In addition, the spacer devices investigated will allow a higher dose of drug to reach the deep lung, which may permit the use of lower dosage regimens with increased therapeutic efficacy.

Trends in antifungal research

With the increasing use of aggressive immunosuppressive therapies in the management of a variety of patient populations, the continuing presence of the AIDS pandemic and the therapeutic advances employed in critical care settings, an increasing number of serious fungal infections are being encountered by today's practicing clinicians. Traditionally, antifungal drug therapy has been delivered by means of intravenous infusion, oral administration, or topical application. Recently, a number of alternative routes of antifungal drug delivery have been developed and investigated, and the traditional means of antifungal administration have been improved to facilitate the therapeutic use of new and reformulated antifungal agents. Organized based on the route of administration, this chapter reviews these advances in antifungal drug delivery.

Increased production of intracellular interleukin-1 receptor antagonist type I in the synovium of mice with collagen-induced arthritis: a possible role in the resolution of arthritis

OBJECTIVE

To examine the patterns of production of interleukin-1 receptor antagonist (IL-1Ra) isoforms and of IL-1beta during arthritis in vivo.

METHODS

Arthritis was induced in DBA/1 mice by immunization with type II collagen, and the production of IL-1Ra isoforms was examined in whole joints and in dissected synovial tissues by reverse transcription-polymerase chain reaction (RT-PCR), RNase protection assay, Western blotting, immunostaining, and in situ hybridization. Production of IL-1beta also was examined using similar approaches.

RESULTS

Production of IL-1Ra increased in the joints during collagen-induced arthritis (CIA). By RT-PCR, secreted IL-1Ra messenger RNA (mRNA) was detected in normal joints, whereas intracellular IL-1Ra type I (icIL-1Ra1) mRNA was only produced in inflamed joints. Western blot studies showed that icIL-1Ra1 protein levels increased in the joints during the course of CIA and that icIL-1Ra3 protein was also present in low amounts. RNase protection assays showed that the IL-1beta:IL-1Ra mRNA ratio was increased in inflamed joints through day 14 of arthritis, whereas a reverse pattern was present at later time points (from day 20 to day 60). Consistent with this finding, immunohistochemistry and in situ hybridization studies confirmed that icIL-1Ra1 was only present in inflamed joints. The histologic evaluation of CIA during the course of the disease indicated a resolution of acute inflammation, since icIL-1Ra1 production increased and the ratio of IL-1beta to total IL-1Ra decreased.

CONCLUSION

Production of IL-1Ra isoforms, particularly icIL-1Ra1, is stimulated in inflamed joints during CIA in mice. The combination of decreased production of IL-1beta and elevated levels of icIL-1Ra1 during the course of CIA was associated with a reduction in inflammatory activity. These results suggest that icIL-1Ra1 may play a role in the resolution of murine CIA.

Influence of water on the solubility of two steroid drugs in hydrofluoroalkane (HFA) propellants

The objective of this research work was to investigate the influence of water level, temperature, and propellant composition on the solubility of two hydrophobic steroid drugs, triamcinolone acetonide (TAA) and beclomethasone diapropionate (BDP). pMDIs containing TAA or BDP, spiked water, and propellant blend with different ratios of HFA 134a and HFA 227 were prepared. The contents of the prepared pMDIs were filtered through a 0.22 mm Acrodisc, syringe filter into a receiving canister after the pMDIs were equilibrated at 15 degrees C, 25 degrees C, 30 degrees C, and 40 degrees C. The drug concentration in the receiving canisters was determined by HPLC and the drug solubility in the propellant blend was calculated. Also, the drug crystal collected on the filter from the donor pMDIs were characterized by x-ray diffraction. The solubility of TAA and BDP varied with propellant composition at all experimental temperatures investigated. The solubility of TAA and BDP increased as the temperature was increased at all propellant compositions and water levels studied, but decreased as the water level in the propellant system was increased at all compositions and temperatures. The x-ray diffraction results indicated that the water in the propellant system had no significant influence on the crystal characteristics of TAA in HFA propellant system, but had a significant impact on the crystal characteristics of BDP was higher than TAA at all propellant compositions, experimental temperatures and water levels investigated. The solubility of TAA and BDP was not only influenced by propellant composition and storage temperature, but also depended on the water level in the propellant system. As a consequence, the crystallinity of the drugs formulated in HFA propellant was influenced by the temperature, propellant composition and the water level in the propellant system. The impact of these factors on the crystallinity of formulated drugs.

Evaluation of TNF-alpha and IL-1 blockade in collagen-induced arthritis and comparison with combined anti-TNF-alpha/anti-CD4 therapy

We have evaluated the effects of anti-TNF-alpha, anti-IL-1, and combined anti-TNF-alpha/anti-CD4 therapy in collagen-induced arthritis. Blockade of TNF-alpha or IL-1 before disease onset delayed, but did not prevent, the induction of arthritis. When treatment was initiated after onset of arthritis, anti-TNF-alpha, anti-IL-1beta, and anti-IL-1R (which blocks IL-1alpha and IL-1beta) were all found to be effective in reducing the severity of arthritis, with anti-IL-1R and anti-IL-1beta showing greater efficacy than anti-TNF-alpha. Anti-IL-1beta was equally as effective as anti-IL-1R, indicating that IL-1beta plays a more prominent role than IL-1alpha in collagen-induced arthritis. An additive effect was observed between anti-TNF-alpha and anti-IL-1R in the prevention of joint erosion and in normalization of the levels of serum amyloid P. Combined anti-TNF-alpha/anti-CD4 therapy also caused normalization of serum amyloid P levels. The therapeutic effect of anti-TNF-alpha plus anti-CD4 was comparable to that of anti-TNF-alpha plus anti-IL-1R, suggesting that combined anti-TNF-alpha/anti-CD4 therapy prevents both TNF-alpha- and IL-1-mediated pathology. Anti-TNF-alpha treatment reduced IL-1beta expression in the joint and, conversely, anti-IL-1beta treatment reduced TNF-alpha expression. Combined anti-TNF-alpha/anti-CD4 treatment almost completely blocked the expression of IL-1beta, thereby confirming the ability of this form of combination therapy to prevent IL-1ss-mediated pathology.

Moisture uptake and its influence on pressurized metered-dose inhalers

The objective of this study was to investigate moisture ingress into pressurized metered dose inhalers (pMDIs) containing hydrofluoroalkane (HFA) propellants and the consequences of this ingress. Moisture ingress into the pMDIs containing tetrafluoroethane (HFA 134a) or heptafluoropropane (HFA 227) was evaluated and modeled. The influence of water level in pMDIs on the stability of pMDIs containing triamicinolone acetonide (TAA) and beclomethasone dipropionate (BDP) in terms of particle growth, fine particle fraction, and drug solubility in the propellant system was evaluated using scanning electron microscopy, particle size analysis, single-stage impaction, and HPLC. The water level in HFA-containing pMDIs increased during storage and the process obeyed a diffusion model. HFA 134a had a greater tendency to take up moisture from the environment than did HFA 227. Unlike TAA, the propensity for particle growth of the suspended BDP in HFA propellants was significantly depressed by the increase in water level in the pMDIs. As a result, the fine particle fraction of the emitted BDP aerosols significantly increased as the water level in the HFA propellant was increased. Moisture ingress into pMDIs containing HFAs occurred during storage. The influence of the increased water level in pMDIs on the physical stability of the pMDI formulation and the dose delivery performance was a function of the composition of the internal lining of the container, the type of drug and propellant, and storage temperature.

Influence of processing and curing conditions on beads coated with an aqueous dispersion of cellulose acetate phthalate

The influence of fluidized-bed processing conditions, as well as curing parameters with and without humidity, on drug release from beads coated with cellulose acetate phthalate (CAP) aqueous dispersion was investigated. Theophylline beads prepared by extrusion-spheronization were coated with diethyl phthalate (DEP)-plasticized CAP dispersion (Aquacoat CPD) using a Strea-1 fluidized-bed coater. The parameters investigated were plasticizer level, outlet temperature, spray rate during coating application and fluidizing air velocities using a half-factorial design. The processing temperature during coating applications was identified as a critical factor among the variables investigated. The release rate significantly decreased when the beads were coated at 36 degrees C compared to those coated at 48 degrees C (P<0.01). Higher coating efficiencies and better coalescence of films were obtained at the lower coating temperature. Above the minimum film-formation temperature (MFFT), drug release in acid decreased as the coating temperature was decreased. Curing at 60 degrees C significantly reduced the drug release for beads coated at 32 degrees C, but had no significant effect on drug release for beads coated at temperatures above 36 degrees C. Curing at 50 degrees C in an atmosphere containing 75% RH (relative humidity), irreversibly converted poor film formation into better coalescence, and increased the mechanical toughness of films. Subsequent removal of the moisture absorbed from beads did not significantly alter the enteric profiles obtained through heat-humidity curing. The extent of coalescence via heat-humidity curing was dependent on the curing temperature, % humidity, curing time and coating temperature. The results demonstrated the importance of the selection of coating temperature for CAP-coated beads and the role of moisture on CAP film formation. Curing with humidity was found to be more effective than without.

A comparative study into the mechanisms of action of anti-tumor necrosis factor alpha, anti-CD4, and combined anti-tumor necrosis factor alpha/anti-CD4 treatment in early collagen-induced arthritis

OBJECTIVE

Anti-tumor necrosis factor alpha (anti-TNFalpha) therapy is very effective in rheumatoid arthritis (RA), whereas depleting anti-CD4 therapy is relatively ineffective. To explain the differences in efficacy between these 2 therapies, we used an animal model of RA to compare their effects on different aspects of the disease process.

METHODS

Mice with collagen-induced arthritis were treated with depleting anti-CD4 monoclonal antibodies (mAb), anti-TNFalpha mAb, or phosphate buffered saline. Another group was given a combination of anti-TNFalpha plus anti-CD4. The treatments were compared for their ability to down-regulate the expression of proinflammatory cytokines and adhesion molecules, reduce the cellularity of the joint, and inhibit Th1 activity.

RESULTS

Anti-TNFalpha significantly reduced the numbers of cells expressing TNFalpha, interleukin-1beta (IL-1beta), very late activation antigen 4 (VLA-4), vascular cell adhesion molecule 1 (VCAM-1), and numbers of CD4+ T cells and macrophages in the joint. Anti-CD4 treatment led to a small reduction in the expression of TNFalpha, IL-1beta, VLA-4, and VCAM-1, but this did not reach statistical significance. Depleting anti-CD4 was also surprisingly ineffective in eliminating CD4+ T cells from the joint. Anti-TNFalpha therapy was also more effective than anti-CD4 in reducing Thl activity, as assessed by the production of interferon-gamma in lymph node cell cultures. There was a synergistic relationship between anti-TNFalpha and anti-CD4 in the reduction of histologic score and inhibition of TNFalpha/IL-1beta expression in the joints.

CONCLUSION

The efficacy of the 3 treatments correlated with their ability to modulate the expression of inflammatory cytokines and adhesion molecules in the joint, reduce the cellularity of the joint, and inhibit Th1 activity. This kind of analysis may prove useful in the testing of novel therapies for RA.

Study of solubility of steroids in hydrofluoroalkane propellants

The solubility of prednisone, hydrocortisone 21-acetate, hydrocortisone, dexamethasone, betamethasone 17-valerate, and danazol in hydrofluoroalkane (HFA) 134a and HFA 227 was determined at 5 degrees C and 25 degrees C. It was found that the solubility of steroid in HFA propellants was related to the melting point and the lipophilicity of the steroid. The solubility of the steroids in the binary system of HFA propellants and ethanol also was investigated in the study. Ethanol significantly increased the solubility of the steroids in HFA propellant. The magnitude of increase was related to the solubility of the corresponding steroid in ethanol alone.

Combination therapy with DMARDs and biological agents in collagen-induced arthritis

There is increasing interest in the use of combination therapy for rheumatoid arthritis and in the possibility of combining the conventional drug approach with newer biological therapies. Animal models of arthritis provide important tools for evaluating novel forms of therapy and for eludicating mechanisms of drug action. In this paper, we review the results of our own research into combination therapy in collagen-induced arthritis using biological therapies such as anti-tumor necrosis factor alpha, anti-CD4, and anti-interleukin 12 monoclonal antibodies, and small molecular weight compounds such as cyclosporin and the phosphodiesterase IV (PDE IV) inhibitor rolipram.

Application of co-grinding to formulate a model pMDI suspension

The objective of this study was to investigate the effect of co-grinding the model drug, triamcinolone acetonide (TAA), with a polymeric surfactant on the in vitro performance of a model pMDI suspension system. The physicochemical properties of TAA after co-grinding with the surfactant, Pluronic F77, were determined by laser light diffraction, helium pycnometry and equilibrium solubility measurements. TAA-surfactant interaction was investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). The suspension characteristics of pMDI formulations prepared with co-ground TAA and surfactant were investigated by determining their in situ sedimentation, rheological profiles and vapor pressure. The performance characteristics of the pMDI formulations were determined by cascade impaction and dose delivery through-the-valve (DDV) measurements. It was found that the presence of Pluronic F77 decreased the solubility of TAA in the propellant medium. Co-grinding TAA particles with Pluronic F77 influenced the particle size distribution, sedimentation and flocculation characteristics of the pMDI suspension formulation. The addition of Pluronic F77 decreased the viscosity of the pMDI formulation. Formulating the suspension pMDI system with co-ground TAA and Pluronic F77 decreased the mass median aerodynamic diameter (MMAD) of the emitted aerosol and increased the percent respirable fraction (%RF). The co-ground TAA and Pluronic F77 pMDI suspension formulation exhibited greater physical stability which was due to the influence of the co-grinding technique on the physicochemical properties of the TAA particle surface and the propellant dispersion medium. The changes induced by co-grinding with Pluronic F77 improved the performance characteristics of a pMDI suspension formulation by stabilizing the suspension and influencing the flocculation characteristics. Co-grinding is a process which may be useful when developing new pMDI systems containing HFA propellants.

CD44 involvement in experimental collagen-induced arthritis (CIA)

CD44 is a pro-inflammatory cell surface molecule that supports cell migration and cell lodgment in target organs. Therefore, CD44 targeting with specific monoclonal antibodies (mAbs) should be useful for the inhibition of collagen-induced arthritis (CIA) as well as other autoimmune diseases that are dependent on inflammatory cells. In the present paper, we confirm and expand previous reports showing the anti-arthritogenic effect of anti-CD44 mAbs directed against constant epitopes of the CD44 receptor. We demonstrate that such anti-CD44 mAbs can induce resistance to CIA after disease onset. Even accelerated disease developed after two injections of type II collagen was markedly inhibited by IM7.8.1 anti-CD44 mAb. Although KM81 anti-CD44 mAb is a less efficient anti-arthritogenic reagent than IM7.8.1, its Fab' fragments partially inhibit CIA. This finding implies that the antibody blocks CD44 function rather than modulating CD44 cell surface expression or mediating Fc-dependent activities. Histopathological analysis revealed that the anti-CD44 mAb markedly reduces the synovial inflammatory cellular response and the consequent damage to the joint. As CD44 is an alternatively spliced multistructural molecule, similar anti-arthritogenic effects may be achieved by mAbs directed against CD44 isoforms expressed on the pathological cells in question, but not on normal cells, thus leaving the physiological functions intact.

Paradoxical effects of adenovirus-mediated blockade of TNF activity in murine collagen-induced arthritis

Collagen-induced arthritis (CIA) is an experimental model of arthritis widely used to dissect the pathogenesis of human rheumatoid arthritis and to identify potential therapeutic targets. Among these, TNF-alpha has been recognized to play an important role. Here we investigate the feasibility and therapeutic efficacy of prolonged blockade of TNF-alpha activity through the adenovirus-mediated gene delivery of a dimeric chimeric human p55 TNFR-IgG fusion protein and compare it to protein therapy in established CIA. A single i.v. administration of the replication-deficient adenovirus yielded microgram serum levels of the chimeric fusion protein and ameliorated CIA for 10 days. Subsequently, benefit was lost and a rebound to greater inflammatory activity was observed despite the continual presence of bioactive TNFR fusion protein. A similar trend was also observed in mice injected directly with comparable amounts of a human TNFR-IgG fusion protein, whereas the administration of a control adenovirus-encoding beta-galactosidase or of a control human IgG1 protein did not significantly affect the disease course. The mechanisms of the rebound of CIA were investigated, and augmented Ab response to collagen type II and TNFR were identified as potential causes. Our results confirm the feasibility of adenovirus-mediated gene delivery of cytokine inhibitors in animal models of autoimmune diseases for investigational purposes and highlight the importance of prolonged studies. Further investigations are needed to optimize ways of exploiting the potential of adenoviral gene therapy in RA.

The midline dose distribution for a three-field radiotherapy technique

At the University of Florida, head and neck cancer often is irradiated using parallel opposed lateral fields (with inferior borders slanted superiorly) and an anterior low neck field. A common criticism is that overlap may occur at the match-line junction of the three fields, resulting in an increased risk of radiation myelitis. One setup for treatment of the oropharynx and two for the larynx were irradiated in an anthropomorphic head and neck phantom made of tissue-equivalent polyacrylamide gel with a two-dimensional thermoluminescent dosimeter array in its sagittal midplane. The results showed that no excess radiation dose was measured at the junction of the three fields. The "spinal cord dose," as percentage of dose to the central axis of the primary field, was as follows: oropharynx setup, 15% to 100%; larynx setup with midline tracheal block, 10% to 90%; larynx setup without tracheal block, 10% to 90%. In conclusion, the University of Florida three-field technique for head and neck cancer produces no measured increase in dose at field junctions.

Influence of micronization method on the performance of a suspension triamcinolone acetonide pressurized metered-dose inhaler formulation

The purpose of this study was to investigate the influence of micronization technique on performance and stability of the model drug formulated in a suspension-based pressurized metered-dose inhaler (pMDI). The model drug, triamcinolone acetonide (TAA), was subjected to ball milling or air-jet milling prior to formulation of the pMDI. The dose delivery characteristics of the emitted aerosol cloud were monitored for the ball-milled, air-jet-milled, and unmicronized TAA pMDI formulations prior to and after storage at 25 and 40 degrees C. Cascade impaction was used to determine the aerodynamic particle size distribution of the emitted dose. Both micronization techniques reduced the drug particle size distribution and the polydispersity of the drug particles to a similar extent, but the ball-milling technique reduced the crystallinity of the drug to a greater degree compared to the air-jet-milling technique. The air-jet-milled and unmicronized TAA pMDI displayed similar aerodynamic particle size distributions of the emitted aerosol and respirable fractions over the storage period. The ball-milled TAA resulted in a pMDI formulation with the smallest aerodynamically sized particles and the highest respirable fraction compared to the air-jet-milled or unmicronized TAA pMDI formulations. The micronization techniques significantly influenced the dose delivery characteristics as a result of different initial particle size distributions, amorphous contents, and surface energies.

Influence of formulation technique for hydroxypropyl-beta-cyclodextrin on the stability of aspirin in HFA 134a

The objective of this study was to determine the influence of the formulation technique for 2-hydroxypropyl-beta-cyclodextrin (HP beta CD) on the stability of aspirin in a suspension-based pressurized metered-dose inhaler (pMDI) formulation containing a hydrofluoroalkane (HFA) propellant. HP beta CD was formulated in a pMDI as a lyophilized inclusion complex or a physical mixture with aspirin. A pMDI formulation containing aspirin alone was used as the control. The chemical stability of aspirin in each pMDI formulation was determined over 6-months storage at 5, 25 and 40 degrees C. The quantity of water taken up into the pMDI canister was determined by Karl Fisher titration after storage for 6 months. Differential scanning calorimetry (DSC) was used to confirm the formation of a complex between HP beta CD and aspirin. Aspirin in the lyophilized inclusion complex exhibited the most significant degree of degradation during the 6-months storage, while aspirin alone in the pMDI demonstrated a moderate degree of degradation. Aspirin formulated in the physical mixture displayed the least degree of degradation. The water uptake study showed that water ingress occurred to the greatest extent for formulations containing aspirin and HP beta CD physical mixture, and to the least extent for formulations containing aspirin alone. Finally, the DSC study indicated that an inclusion complex was formed in situ in the pMDI formulations containing the HP beta CD and aspirin physical mixture. In conclusion, HP beta CD may be used to enhance the stability of a chemically labile drug, but the drug stability may be affected by the method of preparation of the formulation.

Amelioration of collagen-induced arthritis and suppression of interferon-gamma, interleukin-12, and tumor necrosis factor alpha production by interferon-beta gene therapy

OBJECTIVE

To investigate the therapeutic effects and possible mechanisms of action of constitutive expression of interferon-beta (IFNbeta) by syngeneic fibroblasts from DBA/1 mice in the collagen-induced arthritis (CIA) model.

METHODS

Immortalized embryonic DBA/1 fibroblasts were infected with a retrovirus expressing murine IFNbeta. IFNbeta-expressing fibroblasts were then implanted intraperitoneally into mice immunized with bovine type II collagen. The effect of IFNbeta on paw swelling, anticollagen antibody levels, IgG1/IgG2a isotype profiles, arthritis score, histologic joint damage, and cytokine secretion from lymph node cells and from bone marrow-derived macrophages was assessed.

RESULTS

A single injection of IFNbeta-secreting fibroblasts was sufficient to prevent arthritis or to ameliorate existing disease. Thus, IFNbeta reduced the clinical score and paw swelling irrespective of whether the injection was administered before or after disease onset in treated mice, compared with that in the untreated control group (P < 0.05). Histologic findings in the IFNbeta-treated mice were markedly less severe than in the control group (P < 0.001). This effect was accompanied by a decrease in total anticollagen IgG levels, a decrease in anticollagen IgG2a, and an increase in IgG1. In vitro, supernatants from these engineered fibroblasts inhibited collagen-induced interferon-gamma secretion from lymph node cells, and reduced the levels of tumor necrosis factor alpha and interleukin-12 produced by lipopolysaccharide/IFNgamma-treated bone marrow-derived macrophages. This effect was specific, since it was reversed with anti-IFNbeta polyclonal antibodies.

CONCLUSION

These results indicate that IFNbeta, which is currently used as a treatment for relapsing, remitting multiple sclerosis, is a potent immunomodulatory and antiinflammatory cytokine in CIA and should be considered for the treatment of rheumatoid arthritis.

Formulation of a protein with propellant HFA 134a for aerosol delivery

The purpose of this study was to investigate the formulation and delivery of a protein in a pressurized metered-dose inhaler (pMDI) containing HFA 134a as the propellant for aerosol delivery. Ethanol and surfactants, including polyoxyethylene 10 oleyl ether (Brij 97), polyoxyethylene 20 oleyl ether (Brij 98), polyoxyethylene sorbitan monooleate (Tween 80) and Aerosol OT (AOT), were investigated as formulation adjuvants to improve the dose delivery characteristics of the model protein (bovine serum albumin) containing pMDI formulations. The aqueous solution of a surfactant and protein was lyophilized to obtain a solid carrier system of the protein. Readily dispersible suspensions were obtained by suspending this solid carrier system in HFA 134a with ethanol as a dispersing aid. The formulations containing Tween 80 resulted in the highest respirable fraction. This study suggested a potential formulation containing a lyophilized complex of surfactant and protein readily dispersible in HFA 134a for delivering a therapeutic protein to the respiratory tract by inhalation.

Influence of temperature on the emitted dose of an oral metered dose inhaler

The performance of metered dose inhalers is critical for the efficient delivery of drugs to the intended site of deposition in the respiratory tract. The temperature at which metered dose inhaler products are used by patients may influence the physicochemical characteristics of the emitted dose. Product performance characteristics of a metered dose inhaler containing beclomethasone dipropionate and oleic acid in a blend of chlorofluorocarbon propellants, Freon-11 and Freon-12, were determined by cascade impaction analysis and dose delivery through the valve after the metering chamber was loaded and actuated at 4 degrees C, 23 degrees C, and 40 degrees C. The dose delivered from the valve was not affected by the temperature at which the metering chamber was loaded and actuated. The mass median aerodynamic particle size of the emitted aerosol decreased and the percentage respirable fraction increased as the temperature was increased. The geometric standard deviation of the particle size distribution was not significantly affected by the temperature at which the metering chamber was loaded and actuated. The temperature at which a metered dose inhaler is used by a patient may influence the amount of drug that is potentially respirable; therefore, the dose expected to be delivered and the corresponding therapeutic effect may also be affected.

Characterization of an inclusion complex of cholesterol and hydroxypropyl-beta-cyclodextrin

Interactions between endogenous cholesterol and cyclodextrins have been investigated by several researchers, and they found altered skin penetration of some drugs, membrane disruption, and extraction of cholesterol from the large lipoprotein particles or animal fat. In the present study, an inclusion complex composed of cholesterol and hydroxypropyl-beta-cyclodextrin (HPbetaCD) prepared by lyophilization was investigated and characterized in order to confirm these interactions. Five grams of cholesterol were dispersed in 50 ml of 73.2 mM HPbetaCD aqueous solution, mixed for 2 days, and the filtrate lyophilized. A phase solubility study was performed by mixing an excess amount of cholesterol with an aqueous solution containing increasing amounts of HPbetaCD. The amount of cholesterol in solution after mixing for 2 days at 25 degrees C was determined by HPLC. The inclusion complex was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry, and differential scanning calorimetry (DSC). An Ap-type Higuchi phase solubility diagram, DSC, FTIR, and X-ray diffraction demonstrated the formation of an inclusion complex. DSC thermograms indicated that the endothermic peaks of cholesterol and physical mixture of cholesterol with HPbetaCD due to the fusion of drug crystals, were absent in DSC thermograms obtained on the freeze dried inclusion complex. FTIR spectra indicated that some of the absorption peaks in the lyophilized inclusion complex were different from that of the physical mixture of cholesterol and HPbetaCD. X-ray diffraction patterns showed that the pure cholesterol and a physical mixture of cholesterol and HPbetaCD exhibited crystalline characteristics whereas the lyophilized inclusion complex and HPbetaCD displayed amorphous characteristics. The results indicated that the formation of a cholesterol/HPbetaCD inclusion complex is more water soluble than cholesterol alone.

Therapeutic actions of cyclosporine and anti-tumor necrosis factor alpha in collagen-induced arthritis and the effect of combination therapy

OBJECTIVE

To define the mechanisms of action of 2 novel drugs, cyclosporine and anti-tumor necrosis factor alpha (TNFalpha), in collagen-induced arthritis and to determine the effect of combination therapy.

METHODS

Type II collagen-immunized DBA/1 mice with established arthritis were treated with cyclosporine alone, anti-TNFalpha alone, cyclosporine plus anti-TNFalpha, or saline.

RESULTS

Cyclosporine was found to ameliorate arthritis, suppress interferon-gamma (IFNgamma) production by CD4+ T cells, and reduce TNFalpha expression in arthritic joints. However, cyclosporine did not directly inhibit TNFalpha production by macrophages, indicating that the decrease in TNFalpha expression observed in vivo was probably an indirect consequence of the reduction in type 1 T helper cell activity. Anti-TNFalpha also reduced IFNgamma production by T cells, indicating that TNFalpha is involved in the cellular immune response to collagen. Combined treatment with cyclosporine plus anti-TNFalpha had an additive therapeutic effect.

CONCLUSION

Although cyclosporine and anti-TNFalpha target different points in the inflammatory pathway, there is an overlap in the consequences of their actions in vivo.

Influence of propellant composition on drug delivery from a pressurized metered-dose inhaler

Hydrofluoroalkanes (HFAs) are used to replace chlorofluorocarbons (CFCs) as non-ozone-depleting propellants for pressurized metered-dose inhalers (pMDIs). HFA 134a and HFA 227 are used in combination to precisely manipulate the density and vapor pressure of pMDI formulations. The influence of propellant composition on the dose delivery characteristics of a suspension-based pMDI formulation was investigated. The results showed that as the density of the propellant blends approached the density of the suspended drug particles, the formulation became more physically stable and exhibited the most consistent dose delivery and greatest respirable fraction. The mass median aerodynamic diameter of the aerosolized particles contained in the emitted dose also was decreased by using propellant blends with higher vapor pressures. The performance of a suspension-based pMDI formulation was optimized by varying the propellant composition using HFA 134a and HFA 227.

Suppression of TNF-alpha expression, inhibition of Th1 activity, and amelioration of collagen-induced arthritis by rolipram

Rolipram is a type IV phosphodiesterase inhibitor that suppresses inflammation and TNF-alpha production. As anti-TNF-alpha therapy is effective in rheumatoid arthritis, we investigated the effect of rolipram on collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis. Rolipram was administered after the onset of clinical arthritis at doses of 0.5, 3, 5, or 10 mg/kg twice daily, with a dose-dependent therapeutic effect on clinical severity and joint erosion. Immunohistochemical analysis of joints of rolipram-treated mice revealed 67% reduction in TNF-alpha-expressing cells compared with control arthritic mice. In vitro studies using bone marrow-derived macrophages confirmed that rolipram directly suppressed TNF-alpha and IL-12 production following stimulation with IFN-gamma and LPS. The effect of rolipram on T cell activity was studied by measuring Th1/Th2 cytokine production by collagen-stimulated draining lymph node cells from arthritic mice treated in vivo with rolipram. Rolipram reduced IFN-gamma production and increased IL-10, indicating that rolipram down-regulated the ongoing Th1 response to type II collagen. Finally, the effect on CIA of combination therapy was studied using rolipram plus either anti-TNF-alpha or anti-CD4 mAbs. Rolipram plus anti-TNF-alpha was not therapeutically additive, whereas rolipram plus anti-CD4 mAb was clearly additive. This result indicates that the therapeutic effects of rolipram overlap with TNF-alpha blockade, but are complementary to anti-CD4 treatment. It is therefore proposed that a major mechanism of action of rolipram in CIA is suppression of TNF-alpha activity. These findings suggest that type IV phosphodiesterase inhibitors may be effective in pathologic conditions, such as RA, with overexpression of TNF-alpha.

Suppression of TNF-alpha expression, inhibition of Th1 activity, and amelioration of collagen-induced arthritis by rolipram

Rolipram is a type IV phosphodiesterase inhibitor that suppresses inflammation and TNF-alpha production. As anti-TNF-alpha therapy is effective in rheumatoid arthritis, we investigated the effect of rolipram on collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis. Rolipram was administered after the onset of clinical arthritis at doses of 0.5, 3, 5, or 10 mg/kg twice daily, with a dose-dependent therapeutic effect on clinical severity and joint erosion. Immunohistochemical analysis of joints of rolipram-treated mice revealed 67% reduction in TNF-alpha-expressing cells compared with control arthritic mice. In vitro studies using bone marrow-derived macrophages confirmed that rolipram directly suppressed TNF-alpha and IL-12 production following stimulation with IFN-gamma and LPS. The effect of rolipram on T cell activity was studied by measuring Th1/Th2 cytokine production by collagen-stimulated draining lymph node cells from arthritic mice treated in vivo with rolipram. Rolipram reduced IFN-gamma production and increased IL-10, indicating that rolipram down-regulated the ongoing Th1 response to type II collagen. Finally, the effect on CIA of combination therapy was studied using rolipram plus either anti-TNF-alpha or anti-CD4 mAbs. Rolipram plus anti-TNF-alpha was not therapeutically additive, whereas rolipram plus anti-CD4 mAb was clearly additive. This result indicates that the therapeutic effects of rolipram overlap with TNF-alpha blockade, but are complementary to anti-CD4 treatment. It is therefore proposed that a major mechanism of action of rolipram in CIA is suppression of TNF-alpha activity. These findings suggest that type IV phosphodiesterase inhibitors may be effective in pathologic conditions, such as RA, with overexpression of TNF-alpha.

Suppression of collagen-induced arthritis by continuous administration of IL-4

The onset of collagen-induced arthritis in DBA/1 mice is accompanied by a predominantly Th1 response, characterized by production of the proinflammatory cytokines IFN-gamma and TNF-alpha, and a predominance of IgG2a anti-collagen Abs. This study has primarily addressed the effects of continuous administration of exogenous IL-4, a Th2 cytokine, on collagen-induced arthritis in terms of time of onset, clinical symptoms, and histologic changes compared with those in untreated controls. The contributions of Th1 and Th2 cell responses were studied by examining anti-CII IgG subclasses, serum IgE levels, and cytokine production by synovial membrane and lymph node cell cultures. Continuous exposure to IL-4 for 28 days significantly delayed the onset of arthritis from 19 to 37 days and suppressed clinical symptoms. Arthritis occurred approximately 13 to 24 days after treatment ceased. Thereafter, the severity and duration of clinical symptoms were similar to those in control animals, although both joint damage and inflammation at the histologic and cellular levels were less severe than those in untreated controls. During IL-4 treatment, anti-collagen Ab levels were reduced (most significantly those of the IgG2a subclass), histology scores were lower, and the most striking effect was a 1000-fold decrease in TNF-alpha secretion by synovial cells. No significant differences in IgE levels were found between controls and IL-4-treated mice. These data suggest that the anti-inflammatory properties of IL-4 are mediated in part by down-regulation of Th1 responses rather than up-regulation of Th2 responses.

Suppression of collagen-induced arthritis by continuous administration of IL-4

The onset of collagen-induced arthritis in DBA/1 mice is accompanied by a predominantly Th1 response, characterized by production of the proinflammatory cytokines IFN-gamma and TNF-alpha, and a predominance of IgG2a anti-collagen Abs. This study has primarily addressed the effects of continuous administration of exogenous IL-4, a Th2 cytokine, on collagen-induced arthritis in terms of time of onset, clinical symptoms, and histologic changes compared with those in untreated controls. The contributions of Th1 and Th2 cell responses were studied by examining anti-CII IgG subclasses, serum IgE levels, and cytokine production by synovial membrane and lymph node cell cultures. Continuous exposure to IL-4 for 28 days significantly delayed the onset of arthritis from 19 to 37 days and suppressed clinical symptoms. Arthritis occurred approximately 13 to 24 days after treatment ceased. Thereafter, the severity and duration of clinical symptoms were similar to those in control animals, although both joint damage and inflammation at the histologic and cellular levels were less severe than those in untreated controls. During IL-4 treatment, anti-collagen Ab levels were reduced (most significantly those of the IgG2a subclass), histology scores were lower, and the most striking effect was a 1000-fold decrease in TNF-alpha secretion by synovial cells. No significant differences in IgE levels were found between controls and IL-4-treated mice. These data suggest that the anti-inflammatory properties of IL-4 are mediated in part by down-regulation of Th1 responses rather than up-regulation of Th2 responses.

Determination of diazolidinyl urea in a topical cream by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of diazolidinyl urea (DU) in a cream formulation is described. The aqueous phase of the emulsion was separated by centrifugation, removed, filtered, diluted and applied onto the HPLC system. DU was detected by ultraviolet absorption at a wavelength of 214 nm. The calibration curve was linear over the range of 79-553 micrograms/ml, and identical when determined on consecutive days. The relative standard deviation for repeat determinations was less than 0.5%. Recoveries were 97.74-101.72%. This analytical method is useful for quantitation of DU in cream formulations.

Influence of metering chamber volume and water level on the emitted dose of a suspension-based pMDI containing propellant 134a

PURPOSE

To determine the influence of metering chamber volume of a valve and water content of an aerosol formulation containing propellant 134a on dose delivery through the valve (DDV) and aerodynamic particle size distribution of the emitted dose.

METHODS

The drug was admixed with ethanol, sonicated, and metered into cans. Valois DF10 RC valves were crimped onto the cans and propellant 134a was gassed through the valve. The DDV was determined using a dosage sampling tube. Aerodynamic particle size distributions were determined by cascade impaction. The water content was determined by Karl Fisher titration.

RESULTS

The DDV increased linearly and the aerodynamic particle size distribution was not influenced as the metering chamber volume of the valve was increased. More drug was emitted from the valve from the initial actuations of the can than from the end. Valves with larger metering chamber volumes demonstrated less variability in DDV than those with smaller metering chamber volumes for the initial actuations. The DDV determined for actuations at the end of the can decreased as water was added extemporaneously. The mass median aerodynamic diameter (MMAD) increased as the water level was increased in the formulation. The geometric standard deviation (GSD) and percent respirable fraction (RF) were not influenced by metering chamber volume or water content.

CONCLUSIONS

The valve chosen for the development of pressurized metered dose inhaler (pMDI) formulations with propellant HFA 134a must be investigated to determine the uniformity of drug delivery. The presence of water influences the characteristics of the emitted dose.

TNF blockade in rheumatoid arthritis: implications for therapy and pathogenesis

The role of the immune response in rheumatoid arthritis (RA) is a subject of debate, although it is widely believed to be a T-cell-driven disease. Progress is being hindered by lack of convincing evidence of a defined specific antigen initiating or perpetuating the response. Clinical trials using monoclonal antibodies directed against T-cell surface molecules such as CD4. CD5, and CD7 have thus far not provided evidence of efficacy. The negative data may reflect inadequate dosing or could suggest that indiscriminate depletion of T cells is insufficient by itself as a therapeutic strategy. Blocking proinflammatory cytokines (e.g. TNF alpha, IL-1) or augmenting anti-inflammatory cytokines (e.g. IL-10) offers an alternative approach to therapy. Clinical trials using monoclonal anti-TNF alpha have been particularly successful in controlling inflammation and markedly reducing acute phase proteins and cellular ingress. However, because disease invariably relapses, repeated therapy is necessary. Preliminary experience suggests that this is possible. Anti-TNF therapy for RA has defined a molecular target and new approach for treating immuno-inflammatory disorders.