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.

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.

Analysis of glycosaminoglycans induced in newly formed calcium oxalate crystals using an undiluted urine system.

The aim of this study was to examine the effect of sodium pentosan polysulfate (SPP) in an undiluted urine system and to study its relative affinity to calcium oxalate (CaOx) crystals in the presence or absence of heparan sulfate (HS). CaOx crystals were induced with an overload of oxalate above the metastable limit in spun and filtered urine (SF) and ultrafiltered urine (UF). Then, the crystals were dissolved with EDTA (ethylenediaminetetraacetic acid), electrodialysed and lyophilized. The polyanions, HS or SPP were added to the UF prior to the addition of oxalate. Polyanions in crystal matrices were examined by cellulose acetate electrophoresis. Crystal volume and size were suppressed according to the increase of the concentration of SPP when compared with those of the UF. Scanning electron microscopy (SEM) showed marked aggregation of the crystals in the UF and no aggregation in the presence of SPP. HS was the only polyanion found in CaOx crystals formed after overload of oxalate in SF. Crystals formed in UF did not contain any polyanions. When SPP was added to UF, SPP appeared in the crystal matrix in accordance with its concentration. Once HS in physiological concentration was added to the UF containing SPP, HS and SPP obtained from crystals were strongly stained with Alcian blue in electrophoretic study, where SPP is stained stronger than HS. These results suggest that SPP strongly binds to CaOx crystals as well as HS and that HS and SPP competitively bind to the crystal, then, as a result, they are incorporated into the crystals. The fact that SPP suppressed the aggregation of CaOx crystals in undiluted urine showed the possibility that SPP might be one of the useful drugs for preventing CaOx urolithiasis.

Absorption of heparin, LMW heparin and SP54 after subcutaneous injection, assessed by competitive binding assay.

Unfractionated heparin, pentosan polysulphate (SP54) and the low molecular weight heparins CY216 and CY222 were injected subcutaneously at a minimum of weekly intervals into 5 healthy volunteers. The dose was 75 mg in all cases. Concentrations of administered glycosaminoglycan in serial plasma samples and voidings of urine were measured using a competitive binding assay, and biological activity was assessed in plasma using APTT and anti-Xa clotting assays. There was wide individual variation in the absorption of unfractionated heparin as indicated both by the maximal plasma concentrations reached 2-3 h after injection and by the area under the concentration vs. time curve. The efficiency of absorption increased and the individual variation decreased with decreasing molecular weight of the administered glycosaminoglycan. Urinary excretion correlated with plasma concentration, and recovery in the urine also increased with decreasing molecular weight. Similar patterns of uptake and clearance were indicated by the APTT and competitive binding assays, but anti-Xa clotting activity could be detected in the plasma after clearance of the administered glycosaminoglycan.

Enzymatic determination of urinary chondroitin sulphate: applications in renal stone disease and acromegaly.

A method was developed for the determination of urinary chondroitin sulphate (CS), including dermatan sulphate and chondroitin 4 and 6-sulphates, using an enzymatic degradation with chondroitinase-ABC followed by precipitation with Alcian blue, whereby CS was determined as the difference between undigested and chondroitinase digested material. The method was linear in the range 0-100 mg l-1 with a detection limit of 1 mg l-1 and allowed determinations on small urine volumes without pretreatment of the urine. It could be demonstrated that males excreted more CS than females, and growing children had the highest urinary content of CS. Renal calcium stone formers did not differ from healthy controls in urinary CS. Patients with acromegaly had a higher excretion of CS compared with controls. There was also, in these patients, a positive correlation between the serum growth hormone levels and the urinary CS, indicating that CS-excretion may be an estimate of the activity of the pituitary disorder.

Quantitative analysis of a polysulfated xylan (SP54) in urine using gas-liquid chromatography.

A sensitive analytical method for the quantitation of a polysulfated xylan (SP54) in urine has been developed. SP54 and urinary glycosaminoglycans have been isolated from urine using cetylpyridinium chloride. This method removes all glycosaminoglycans with molecular weights less than 3000 Da. Following isolation, SP54 and urinary glycosaminoglycans have been selectively hydrolyzed under conditions (0.5 M HCl/105 degrees C/30 min) which produce an efficient yield of xylose from SP54 but not from the glycosaminoglycans. Xylose derived from SP54 has subsequently been determined using gas-liquid chromatography. Levels of SP54 down to 10 micrograms/ml have been determined using this technique.