The oral bioavailability of pentosan polysulphate sodium in healthy volunteers

Repurposing pentosan polysulfate sodium as hyaluronic acid linked polyion complex nanoparticles for the management of osteoarthritis: A potential approach

Osteoarthritis is still a disease burden for pharmaceutical scientists and strategy makers. It is associated with the chronic inflammation of joints especially weight-bearing joints like knee, hip, backbone, and phalanges. NSAIDs that are used for the management of inflammation associated with osteoarthritis have high side effects related to gastric upset, gastric ulcer, and long term treatment associated with liver and kidney damage. Nanotechnology has gained a huge scope for the management of arthritis as it can reach out to the deep inside the cell and alter cellular physiology as desired. The present study hypothesizes the use of polyion complex nanoparticles of hyaluronic acid linked Pentosan polysulfate sodium, a disease-modifying agent for the treatment of osteoarthritis administered through transdermal route. The hypothesis involves the use of drug repurposing as the drug was initially approved for interstitial cystitis, a condition of the urinary bladder associated with pain and swelling. Being very low oral bioavailability and gastric irritation profile, the transdermal route would be beneficial. To overcome the problem associated with the oral route, there is a need for the targeted approach that will particularly reach at inflammatory sites. Thereby transdermal delivery of hyaluronic acid linked Pentosan polysulfate sodium through polyion complex nanoparticle therapy will be a novel therapeutic approach to combat osteoarthritis.

Temperature-responsive silk-elastinlike protein polymer enhancement of intravesical drug delivery of a therapeutic glycosaminoglycan for treatment of interstitial cystitis/painful bladder syndrome

Interstitial cystitis (IC), also known as painful bladder syndrome, is a debilitating chronic condition with many patients failing to respond to current treatment options. Rapid clearance, mucosal coating, and tight epithelium create strong natural barriers that reduce the effectiveness of many pharmacological interventions in the bladder. Intravesical drug delivery (IDD) is the administration of therapeutic compounds or devices to the urinary bladder via a urethral catheter. Previous work in improving IDD for IC has focused on the sustained delivery of analgesics within the bladder and other small molecule drugs which do not address underlying inflammation and bladder damage. Therapeutic glycosaminoglycans (GAG) function by restoring the mucosal barrier within the bladder, promoting healing responses, and preventing irritating solutes from reaching the bladder wall. There is an unmet medical need for a therapy that provides both acute relief of symptoms while alleviating underlying physiological sources of inflammation and promoting healing within the urothelium. Semi-synthetic glycosaminoglycan ethers (SAGE) are an emerging class of therapeutic GAG with intrinsic anti-inflammatory and analgesic properties. To reduce SAGE clearance and enhance its accumulation in the bladder, we developed a silk-elastinlike protein polymer (SELP) based system to enhance SAGE IDD. We evaluated in vitro release kinetics, rheological properties, impact on bladder function, pain response, and bladder inflammation and compared their effectiveness to other temperature-responsive polymers including Poloxamer 407 and poly(lactic-co-glycolic acid)-poly(ethylene glycol). SAGE delivered via SELP-enhanced intravesical delivery substantially improved SAGE accumulation in the urothelium, provided a sustained analgesic effect 24 h after administration, and reduced inflammation.

Clinical trials

Arguably the most important goal of prion research is the discovery of a safe and effective treatment for the human diseases. The final stages of the pathway to develop a treatment require clinical trials. Choices about how a trial is designed and conducted have a large impact on the chances of success. The gold-standard large randomized double-blind placebo-controlled study, which minimizes sources of bias and has been incredibly successful in other diseases, has been hard to achieve in Creutzfeldt-Jakob disease principally because of the rarity and rapidity of the clinical syndrome. To date, clinical trials have been restricted to repurposed compounds, doxycycline, quinacrine, pentosan polysulfate (PPS), and flupertine. In most cases, these trials have used survival as an endpoint, which, whilst clearcut, has limitations. Biomarkers have played a strong role in diagnosis and entry criteria, but only a limited role as secondary outcome measures. Recent developments suggest some possible improvements in trial design by use of new outcome measures that have more favorable properties, and biomarkers of neuronal damage and/or prion seeding activity. Alternative patient populations, including those at risk of genetic forms of prion disease, warrant more consideration. In the future, improved trial designs will be employed to test compounds designed specifically to treat prion diseases.

Pharmacokinetics and Pharmacodynamics of Warfarin When Coadministered With Pentosan Polysulfate Sodium

The effect of pentosan polysulfate sodium on warfarin pharmacokinetics and pharmacodynamics was investigated in healthy subjects. Warfarin was titrated to an international normalized ratio between 1.4 and 1.8. Subjects continued their titrated dose of warfarin and received pentosan polysulfate sodium 100 mg or placebo every 8 hours for 7 days. The Cmax of R- and S-warfarin was approximately 840 to 890 ng/mL and 680 to 730 ng/mL, respectively, and was similar in the absence and presence of pentosan polysulfate sodium. The half-life for R- and S-warfarin was 52 to 56 hours and 36 to 40 hours, respectively. Prothrombin time, partial thromboplastin time, and the international normalized ratio for warfarin + placebo and warfarin + pentosan polysulfate sodium were comparable. The AUC(INR) indicated no treatment effect (P = .772); however, there was a period effect. Analysis of variance for the treatments by period indicated no treatment effect (P > .1). Adverse events were mild and included headache, epistaxis, and rash. Most adverse events were unrelated to treatment and were seen during warfarin titration. Pentosan polysulfate sodium did not affect warfarin pharmacokinetics or pharmacodynamics.

Metabolism of [3H]pentosan polysulfate sodium (PPS) in healthy human volunteers

Pentosan polysulfate sodium (PPS) is the active ingredient in ELMIRON, a drug approved for the relief of bladder pain associated with interstitial cystitis. The study objective was to characterize the pharmacokinetic and metabolic profiles of PPS following oral dosing of [3H]PPS. As specific assays for PPS do not exist, metabolic profiling was accomplished through multiple fraction collections and radiochromatographic techniques. Two groups of eight healthy female subjects sequentially received a single oral dose of 200 microCi [3H]PPS supplemented with 300 mg unlabelled PPS or 300 microCi [3H]PPS supplemented with 450 mg unlabelled PPS. Most of the administered dose (84%) was excreted in faeces as intact PPS, and a smaller percentage (6%) was excreted in urine. In summary, orally administered PPS was very poorly absorbed, with the majority of the drug being excreted in faeces as intact PPS and in urine as low molecular weight and desulfated PPS.

Molecular size affects urine excretion of pentosan polysulfate

PURPOSE

In human subjects only a small percent of oral PPS is found in urine. Commercially available PPS is a heterogeneous mixture with varying molecular weights. Our hypothesis was that only the low molecular weight fraction reaches the urine.

MATERIALS AND METHODS

Urine was obtained from patients with IC who were chronically receiving PPS. The amount and molecular size of PPS in the urine were determined by enzyme-linked immunosorbent assay and molecular sieve chromatography. PPS was purified from Elmiron capsules and fractionated into LMW and HMW fractions. Urine recovery of PPS was measured in rabbits after oral or intravenous administration of unfractionated, LMW or HMW PPS.

RESULTS

The median urine PPS level in 34 patients with IC was 1.2 microg/ml (range 0.5 to 27.7). All PPS recovered from IC urine was LMW. After intravenous administration in rabbits the median recovery in urine was 47.2% (range 19.7% to 73.2%) for unfractionated PPS, 74.6% (range 31.4% to 96.3%) for LMW and 3.3% (range 2.5% to 5.0%) for HMW. After oral administration in rabbits the median recovery in urine was 7.4% (range 2.1% to 46.0%) for LMW and 0.10% (range 0.0% to 0.3%) for HMW.

CONCLUSIONS

In patients with IC who are on oral PPS the PPS recovered in the urine is all of LMW. In rabbits the HMW fraction of PPS is recovered in small amounts from urine after intravenous administration and not at all after oral administration.

Pentosan Polysulfate

Pentosan polysulfate (pentosan polysulfate sodium; ELMIRON), a heparin-like, sulfated polysaccharide, is used to manage bladder pain and discomfort in adults with interstitial cystitis (IC). Preliminary clinical models suggest that pentosan polysulfate repairs damaged glycosaminoglycan (GAG) layers lining the urothelium and in vitro data suggest it may provide an anti-inflammatory effect in patients with IC. Pentosan polysulfate shows beneficial effects in a proportion of patients with IC in terms of the improvement of a patient's overall condition and the relief of pain, and it is a generally well tolerated therapy. It is the only US FDA-approved oral treatment for the relief of bladder pain or discomfort associated with IC, and data support its role as an important option in the treatment of patients with IC.

Is there a role for pentosan polysulfate in the prevention of calcium oxalate stones?

The clinical role for pentosan polysulfate (PPS) in the prevention of calcium oxalate urolithiasis is not known. Crystallization and aggregation are important steps in calcium oxalate stone formation, and PPS has been shown to inhibit these steps, both in vitro and in vivo. In addition, PPS has a role in repairing injured urothelium and inhibiting adhesion to epithelial defects. A randomized double-blind placebo-controlled study appears warranted to assess the utility of PPS in the prevention of recurrent calcium oxalate stones.

Tissue distribution of [14C]sucrose octasulfate following oral administration to rats

PURPOSE

Aluminum sucrose octasulfate (SOS) is used clinically to prevent ulcers. Under physiologic conditions, the sodium salt of this drug can be formed. Our objective was to determine whether sodium SOS was absorbed when administered orally. In addition to furthering our understanding of aluminum SOS, this study also aimed to clarify how other polyanionic drugs, such as heparin and low-molecular-weight heparins, are absorbed.

METHODS

[14C]-labeled and cold sodium SOS (60 mg/kg) were given to rats by stomach tube. Radioactivity was counted in gut tissue, gut washes, and nongut tissue (i.e., lung, liver, kidney, spleen, endothelial, and plasma samples) at 3 min, 6 min, 15 min, 30 min, 60 min, 4 h, and 24 h, and in urine and feces accumulated over 4 h and 24 h.

RESULTS

Peak radioactivity was found in the tissue and washes of the stomach, ileum, and colon at 6 min, 60 min, and 4 h, respectively, showing progression through the gut. Gut recovery accounted for 84% of the dose at 6 min but only 12% of the dose at 24 h, including counts from feces. Radioactivity was recovered from nongut tissue (averaging 8.6% of the dose) and accumulated urine (18% of the dose at 24 h). When total body distribution was considered, the recovery of radioactivity was greater for the endothelium than for plasma (peak percentage of the dose was 65% at 15 min, 20% at 3 min, 5% from 20 to 240 min for the vena cava, aortic endothelium, and plasma, respectively).

CONCLUSIONS

Results indicate that sodium SOS is absorbed, agreeing with previous studies demonstrating the oral absorption of other sulfated polyanions. Endothelial concentrations must be considered when assessing the pharmacokinetics of these compounds. The measured plasma drug concentrations reflect the much greater amounts of drug residing with the endothelium.

Lysosomal-storage disorder induced by elmiron following 90-days gavage administration in rats and mice

Elmiron, a highly sulfated, semisynthetic pentose polysaccharide with properties similar to heparin, is used for the treatment of interstitial cystitis. Thirteen-week gavage studies were conducted by administering the drug in deionized water to F344/N rats and B6C3F1 mice once daily, 5 days per week for up to 13 consecutive weeks, at doses of 0, 63, 125, 250, 500, and 1,000 mg/kg body weight. No significant drug-related effects were observed in body weight, survival, clinical, and necropsy results. Significant organ weight increases were seen in the liver, lungs, and spleen of both species and the kidneys of rats, mainly in groups treated with 250 mg/kg/day and above. Hematological analysis indicated increases for both species in the white blood cell and lymphocyte counts. Sites of toxicity identified histopathologically were the rectum, liver, mesenteric and mandibular lymph nodes (both sexes), spleen (mice only), and lungs and kidneys (rats only). Lesions consisted mainly of infiltration into multiple tissues of vacuolated histiocytes, which, by histochemical investigation, indicated the presence of neutral and acidic mucins and lipidic material within the vacuoles. Transmission electron microscopy identified these vacuoles as lysosomal structures that exhibited a variety of contents. On the basis of our findings, we propose that Elmiron was absorbed through the focally disrupted rectal mucosa, was deposited in the lamina propria, accumulated within macrophages, and then was distributed by these cells or as a free chemical via the lymphatics and blood, to the various organ sites manifesting histiocytic infiltration. The cytoplasmic membrane-bound structures within macrophages were lysosomes containing membranous material of cellular origin and, perhaps, remnants of the deposited test material, Elmiron.