Biodisposition of PEG-coated lipid microspheres of indomethacin in arthritic rats

Stimuli-responsive Drug Delivery Systems as an Emerging Platform for Treatment of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a systemic autoimmune disease accompanied by chronic inflammation. Due to the long-term infiltration in inflammatory sites, joints get steadily deteriorated, eventually resulting in functional incapacitation and disability. Despite the considerable effect, RA sufferers treated with current drug therapeutic efficacy are exposed to severe side effects. Application of Drug Delivery Systems (DDS) has improved these situations while the problem of limited drug exposure remains untackled. Stimuli-responsive DDS that are responsive to a variety of endogenous and exogenous stimuli, such as pH, redox status, and temperature, have emerged as a promising therapeutic strategy to optimize the drug release. Herein, we discussed the therapeutic regimes and serious side effects of current RA therapy, as well as focused on some of the potential stimuliresponsive DDS utilized in RA therapy. Besides, the prospective room in designing DDS for RA treatment has also been discussed.

Tunable Two-Compartment On-Demand Sustained Drug Release Based on Lipid Gels

The binary-lipid system of soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) can hydrate to gels on contacting with aqueous mediums, which has emerged as a versatile and promising delivery matrix for extended drug release applications. In the present work, we have characterized the gelation process of this SPC/GDO lyotropic gel (SGLG) system by rheology and evaluated the drug release profiles from the SGLG formulations with different SPC/GDO mass ratios. Our study has demonstrated that simply adjusting the SPC/GDO mass ratio can tune the lipid gelation behavior and modulate the drug release profiles. More importantly, the drug release from the SGLG formulations follows a two-compartment (fast and slow release compartments) release kinetics that has not been reported before. We posit that the fast release compartment corresponds to the passive diffusion of the drug during the early stage of the gel formation. After the boundary gel phase generation, the drug release is then dominated by the slow diffusion process from SGLG. The pharmacokinetic studies in rats match well with the in vitro studies, suggesting that the binary-lipid formulation is an excellent candidate for on-demand sustained drug delivery system.

Utilization of nanoparticle technology in rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is one of the common and severe autoimmune diseases related to joints. This chronic autoimmune inflammatory disease, leads to functional limitation and reduced quality of life, since as there is bone and cartilage destruction, joint swelling and pain. Current advances and new treatment approaches have considerably postponed disease progression and improved the quality of life for many patients. In spite of major advances in therapeutic options, restrictions on the routes of administration and the necessity for frequent and long-term dosing often result in systemic adverse effects and patient non-compliance. Unlike usual drugs, nanoparticle systems are planned to deliver therapeutic agents especially to inflamed synovium, so avoiding systemic and unpleasant effects. The present review discusses about some of the most successful drugs in RA therapy and their side effects and also focuses on key design parameters of RA-targeted nanotechnology-based strategies for improving RA therapies.

Application of liposomes in treatment of rheumatoid arthritis: quo vadis

The most common treatments for rheumatoid arthritis include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, disease modifying antirheumatic drugs (DMARDs), and some biological agents. However, none of the treatments available is able to achieve the ultimate goal of treatment, that is, drug-free remission. This limitation has shifted the focus of treatment to delivery strategies with an ability to deliver the drugs into the synovial cavity in the proper dosage while mitigating side effects to other tissues. A number of approaches like microemulsions, microspheres, liposomes, microballoons, cocrystals, nanoemulsions, dendrimers, microsponges, and so forth, have been used for intrasynovial delivery of these drugs. Amongst these, liposomes have proven to be very effective for retaining the drug in the synovial cavity by virtue of their size and chemical composition. The fast clearance of intra-synovially administered drugs can be overcome by use of liposomes leading to increased uptake of drugs by the target synovial cells, which in turn reduces the exposure of nontarget sites and eliminates most of the undesirable effects associated with therapy. This review focuses on the use of liposomes in treatment of rheumatoid arthritis and summarizes data relating to the liposome formulations of various drugs. It also discusses emerging trends of this promising technology.

Targeting sites of inflammation: intercellular adhesion molecule-1 as a target for novel inflammatory therapies

Targeted drug delivery to sites of inflammation will provide effective, precise, and safe therapeutic interventions for treatment of diverse disease conditions, by limiting toxic side effects and/or increasing drug action. Disease-site targeting is believed to play a major role in the enhanced efficacy observed for a variety of drugs when formulated inside lipid vesicles. This article will focus on the factors and mechanisms involved in drug targeting to sites of inflammation and the importance of cell adhesion molecules, in particular intercellular adhesion molecule-1, in this process.

Preparation and characteristics of lipid nanoemulsion formulations loaded with doxorubicin

Purpose

Safe and effective lipid nanoemulsion (LNE) formulations for the antitumor delivery of doxorubicin is designed.

Methods

LNEs composed of medium-chain triglyceride, soybean oil, lecithin, and doxorubicin are prepared by a solvent-diffusion method in an aqueous system. The effects of lipid material composition and polyethylene glycol (PEG)ylation on the size, drug encapsulation efficiency, and stability of LNEs are investigated. Based on in-vitro cytotoxicity and cellular uptake tests of A549 (human lung carcinoma) cells, in-vivo biodistribution, antitumor activity, and cardiac toxicity are further examined using nude mouse bearing A549 tumor.

Results

The LNE size decreases from 126.4 ± 8.7 nm to 44.5 ± 9.3 nm with increased weight ratio of medium-chain triglyceride to soybean oil from 1:4 to 3:2, whereas the encapsulation efficiency of doxorubicin is slightly reduced from 79.2% ± 2.1% to 71.2% ± 2.9%. The PEGylation of LNE by 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(PEG)2000] (DSPE-PEG 2000) does not significantly change the size and drug encapsulation efficiency. Three-month storage at room temperature and lyophilization process does not affect the drug encapsulation efficiency, whereas the size slightly increases to almost 100 nm. The in-vitro drug-release profiles of LNEs suggest that the present formulation can prolong drug release for 48 hours. LNEs can be internalized into tumor cells in vitro and efficiently accumulate in tumor tissues in vivo by passive targeting. Analysis results of in-vitro and in-vivo antitumor activities reveal that doxorubicin-loaded LNE exerts a therapeutic effect similar to that of the commercial Adriamycin. Moreover, the toxicity of doxorubicin, particularly its cardiac toxicity, is reduced.

Conclusion

The present LNE formulation of doxorubicin can effectively suppress tumor growth and improve the safety of Adriamycin.

The shape/morphology balance: a study of stealth liposomes via fractal analysis and drug encapsulation

PURPOSE

Fractal analysis was used as a tool in order to study the morphological characteristics of PEGylated liposomes. We report on the morphological characteristics of stealth liposomes composed of DPPC and DPPE-PEG 3000 in two dispersion media using fractal analysis.

METHODS

Light scattering techniques were used in order to elucidate the size, the morphology and the surface charge of PEGylated liposomes as a function of PEGylated lipid concentration and temperature. Fluorescence spectroscopy studies revealed a microenvironment of low polarity inside the liposomal membranes.

RESULTS

All formulations were found to retain their physicochemical characteristics for at least 3 weeks. The hydrodynamic radii (Rh) of stealth liposomes were stable in the process of heating up to 50°C; while the fractal dimension values (df) which correspond to their morphology, have been changed during heating. Hence, these results are a first indication of the presence of a heterogeneous microdomain structure of the stealth liposomal system. The amphiphilic drug indomethacin (IND) was successfully encapsulated within the liposomes and led to an increased size of stealth liposomes, while the morphology of liposomal vectors changed significantly at the highest molar ratio of PEGylated lipid.

CONCLUSIONS

We can state that this approach can promote a new analytical concept based on the morphological characteristics and quantify the shape of drug carriers complementary to that of the conventional analytical techniques.

In-vitro and in-vivo evaluation of austocystin D liposomes

OBJECTIVES

The purpose this study is to enhance the anti-tumour activity of austocystin D (AD) by AD-loaded liposomes (AD-Ls).

METHODS

AD-Ls were prepared by the film dispersion-ultrasonication method and characterized in terms of particle size and zeta potential, encapsulation efficiency and in-vitro drug release. In vivo, the pharmacokinetics, biodistribution and anti-tumour effect were also compared with those of the solution.

KEY FINDINGS

The obtained liposomes were a mildly translucent suspension, with a particle size of 71.26 ± 6.43 nm, a polydispersity index of 0.259 ± 0.017 and a zeta potential of -9.9 ± 1.8 mV. Transmission electron microscope examination showed that the liposomes had a spherical shape and a multilayer structure. The encapsulation efficiency ofAD-Ls was 83.74 ± 1.26%. AD was continuously released from liposomes up to 72 h in in-vitro experiments. The growth of HT-29 tumours in animal models was controlled more effectively by AD-LS than by AD solution. Pharmacokinetic study showed that AD-Ls had higher t½β and mean retention time. Biodistribution results in tumour-bearing mice showed that the AD-LS could target to liver and tumour.

CONCLUSIONS

This study indicates that AD-Ls are a potential carrier of AD for the treatment of tumours in the liver, increasing the cure efficiency and decreasing the side effects on other tissues.

Drug targeting systems for inflammatory disease: one for all, all for one

In various systemic disorders, structural changes in the microenvironment of diseased tissues enable both passive and active targeting of therapeutic agents to these tissues. This has led to a number of targeting approaches that enhance the accumulation of drugs in the target tissues, making drug targeting an attractive strategy for the treatment of various diseases. Remarkably, the strategic principles that form the basis of drug targeting are often employed for tumor targeting, while chronic inflammatory diseases appear to draw much less attention. To provide the reader with a general overview of the current status of drug targeting to inflammatory diseases, the passive and active targeting strategies that have been used for the treatment of rheumatoid arthritis (RA) and multiple sclerosis (MS) are discussed. The last part of this review addresses the dualism of platform technology-oriented ("one for all") and disease-oriented drug targeting research ("all for one"), both of which are key elements of effective drug targeting research.

Nanotherapeutic approaches for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common inflammatory disease characterized by progressive bone and cartilage destruction, resulting in severe functional limitations, shortened lifespan, and increased mortality rates. Recent advances and new treatment approaches have significantly delayed disease progression and improved the quality of life for many patients. Yet few patients attain or can be maintained in disease remission without continuous immunosuppressive therapy. In addition, a sizable portion of patients also fails to respond or eventually develops tolerance to current therapies. Thus there is a continued need for the development of new therapeutic strategies for the treatment of RA. Unlike conventional drugs, nanosystems are designed to deliver therapeutic agents specifically to the site of inflammation, therefore avoiding potential systemic and off-target unwanted effects. They allow investigators to consider or reconsider therapeutic agents that were previously deemed too toxic to deliver through a systemic route. This article reviews recent nanotechnology-based strategies that are being developed for the treatment of inflammatory arthritis.

Prednisolone-loaded PLGA microspheres. in vitro characterization and in vivo application in adjuvant-induced arthritis in mice

This study aimed at preparation of a sustained-release steroidal treatment for chronic inflammatory conditions, such as rheumatoid arthritis. To achieve such a goal, biodegradable poly-lactide-co-glycolide prednisolone-loaded microspheres were prepared using o/w emulsion solvent evaporation method. Formulation parameters were adjusted so as to optimize the microsphere characteristics. The prepared microspheres exhibited smooth and intact surfaces, with average size range not exceeding 65 microm. The encapsulation efficiency percent of most microsphere formulations fell within the range of 25-68%. Drug release from these microspheres took place over 4 weeks, with near-to-zero-order patterns. Two successful formulations were chosen for the treatment of unilateral arthritis, induced in mice using Freund's complete adjuvant (FCA). Inflammatory signs of adjuvant arthritis included severe swelling of the FCA-injected limbs, in addition to many histopathological lesions. These included inflammatory cell infiltration, synovial hyperplasia, cartilage, and bone erosion. Parenteral administration of the selected formulae dramatically reduced the swelling of the FCA-injected limbs. In addition, histological examination revealed that the microsphere treatment protocol efficiently protected cartilages and bones of mice, injected with FCA initial and booster doses, from erosion. These results could not be achieved by a single prednisolone dose of 5 mg/kg.

In vitro and in vivo evaluation of mPEG-PLA modified liposomes loaded glycyrrhetinic acid

In order to prolong the in vivo residence of glycyrrhetinic acid, a liposomes with surface modified by methoxy poly(ethyleneglycol) (mPEG)-PLA was prepared for the first time. The liposomes (C-LP) and long-circulating liposomes (LC-LP) were prepared by film-dispersion method using soybean phospholipid/cholesterol mixture (1:0.5 mol/mol), containing 5% (w/w) sodium deoxycholate, and 2% (w/w) mPEG-PLA (only for LC-LP). The diameter of LC-LP was 243.3+/-17.1 nm. The pharmacokinetics behaviors of the conventional injection and liposomes (C-LP and LC-LP) were compared after a single intravenous injection to rats. Pharmacokinetic parameters were calculated based on a two-compartment open model analysis. LC-CP had a 1.7-fold longer residence time (MRT), a 2.75-fold larger AUC and a 0.4-fold lower clearance compared with conventional injection, respectively. These results combined suggested that the LC-CP had a well-improved residence in rats.

Biodistribution in mice and severity of damage in rat lungs following pulmonary delivery of 9-nitrocamptothecin liposomes

This study was designed to investigate in vitro release, in vivo tissue distribution and the damage to the lungs of 9-nitrocamptothecin (9-NC) liposomes. In vitro release of 9-NC from liposomes was carried out in phosphate buffer saline solution (PBS) pH 7.4. The tissue distribution of 9-NC liposomes and 9-NC solution was determined after pulmonary delivery to mice. The tissue distribution of 9-NC liposomes after intravenous administration was also studied. The changes of pulmonary edema index and histology of lungs in rats were investigated to evaluate the severity of the damage after pulmonary delivery. The results showed that 9-NC was continuously released from liposomes in PBS pH 7.4 for 24h at 37 degrees C. After pulmonary delivery, the mean residence time (MRT) of 9-NC liposomes in the lungs was 3.4 times as long as that of 9-NC solution and the total AUC0-t of all tissues in mice of the liposomes was 2.2-fold higher than that of the solution, indicating that the liposomes had sustained-release characteristics. Following intravenous administration and pulmonary delivery, the targeting efficiency (Te) to the lung of 9-NC liposomes was 0.14 and 2.02, respectively, which showed that intratracheal instillation can deliver the drug mainly to the lung and decrease the accumulation of the drug in other tissues at different concentrations. The pulmonary edema index and the histological changes of the lungs in 9-NC liposome group were significantly different from those in 9-NC solution group. The lung damage by liposomes was less severe than that by solution. Pulmonary delivery of 9-NC liposomes could directly deliver the drug to the lung and make the drug accumulate in the lung with sustained-release characteristics, changing the disposition behavior in vivo, decreasing the toxic and side effects on other tissues and reduce the severity of damage to lungs following intratracheal instillation.

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.