Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

Abstract

Hyaluronate (HA) is a glycosaminoglycan ubiquitously distributed in organisms. It has a linear structure without side chains, and a molecular weight of 10 4 to 10 7 . The huge molecular mass characterizes the physiologic and physicochemical properties of HA. High-molecular-weight HA forms entangled networks, having unique viscoelasticity and waterholding ability.1) The characteristics are molecular-weightsensitive, and yet, high molecular weight HA is easily depolymerized by various physical and chemical factors. There are many reports about HA depolymerization by photo, 2,3) thermal, 2,4) mechanical 2,5) and chemical actions. 6,7) Previously, we described HA depolymerization by phenothiazines and sulfacetamide with UV irradiation. 7) These drugs are known to cause dermatological or ophthalmic phototoxicity in patients receiving them in the long term. We have revealed the hydroxyl radicals and hydrated electrons generated during photodegradation of the drugs to be the active chemicals for HA depolymerization.Tetracyclines have also been reported to exhibit phototoxic and photoallergic reactions, with certain radicals proposed to account for in vivo and in vitro toxicity. 8,9) In this paper, the depolymerization of HA by tetracyclines, expressly oxytetracycline (OTC), was investigated. From depolymerization profiles under various conditions, the probable causative derivative was identified. ExperimentalMaterials Two sodium HA samples were used: one was extracted from culture medium of Streptococcus equi, with a weight average molecular weight (M w ) of 2.6ϫ10 6 , and the other was isolated from rooster comb, with a M w of 1.1ϫ106 . Sodium alginate of medium viscosity from kelp was a commercial product of Sigma Chemical Co. Tetracycline hydrochlorides were purchased from Sigma Chemical Co. or Wako Chemical Co. They were used without further purification. Their chemical structures are listed in Table 1. Other reagents were of analytical grade. All the water used was distilled once and then Millipore filtered.Sample Preparation Polymer solutions were mixed with tetracycline solutions to make at final concentrations of 0.1% in 0.2 M NaCl. They were incubated in test tubes in a thermostated water bath. At the desired time, a portion was removed, appropriately diluted and after drugs were eliminated by solid-phase extraction on Sep-Pak C 18 cartridges, the molecular weight was measured. For studies under anaerobic conditions, glass ampules were used in place of test tubes. Solutions in ampules were de-aerated by 10-min nitrogen bubbling, immediately before the necks of the ampules were sealed with a burner. For UV irradiation, lamps (100 V, 5 W) with 254 nm or 365 nm for TLC spot detection were employed. The distance of the vessels from the light source was set at 5 cm. In the experiments with 254 nm irradiation, the vessels were squared quartz cells.Molecular Weight Measurement M w of HA was measured using a size exclusion chromatography (SEC) equipped with a low angle laser light scattering (LALLS). SEC-LALLS (Tosoh ...

Comparative study of hyaluronic derivatives: rheological behaviour, mechanical and chemical degradation

“…5 shows the partial depolymerisation related to the initial Mw. Under our incubation conditions, the OTC-HA ratio was equivalent (250 l HA and 250 l OTC at three different concentrations), meaning that the interaction of OTC with HA was lower than in the experiments of Miyazaky et al [8], where tetracycline solutions were mixed with HA at final concentration of 0.1%. These authors obtained high levels of depolymerisation (over 70%) after 10 h of incubation at 37 • C with 4 mM OTC.…”

“…doi:10.1016/j.ijbiomac.2004.12.003 molecular weight HA is readily depolymerised by several different physical and chemical factors. There are many reports about HA depolymerisation by photo, thermal, mechanical and chemical actions [8]. Miyazaki et al [9] reported HA depolymerisation by phenothiazines and sulfacetamide with UV irradiation.…”

Free radical scavenging properties of mannitol and its role as a constituent of hyaluronic acid fillers: a literature review

“…Tetracyclines are photosensitive and release ROS when exposed to light or heat, which is a frequent cause of phototoxicity induced by these antibiotics. Incubation of HA at 37°C with a solution of oxytetracycline resulted in the gradual depolymerization of HA . The addition of mannitol to the solution did not inhibit the decomposition of oxytetracycline but did protect HA from damage.…”

Flow field‐flow fractionation and multiangle light scattering for ultrahigh molecular weight sodium hyaluronate characterization

“…Owing to its biological safety and rheological characteristics, solutions of intact or degraded forms of NaHA have versatile uses in ophthalmic surgery as a substitute for vitreous humor, in arthritis treatment using relatively high MW molecules (41 Â 10 6 ), and in wound repair and cosmetological applications with lower MW species (o1 Â 10 6 ) [2,[5][6][7][8][9]. In addition, since NaHA can absorb large amounts of water, it can be utilized as a skin moisturizer and in hydrogel formation [5][6][7][8]. Furthermore, it also aids in the spatial arrangement of tissue due to its visco-elastic properties [8].…”

“…In addition, since NaHA can absorb large amounts of water, it can be utilized as a skin moisturizer and in hydrogel formation [5][6][7][8]. Furthermore, it also aids in the spatial arrangement of tissue due to its visco-elastic properties [8]. Since the biological or pharmaceutical applications of NaHA are related to the molecular size and structure in aqueous solution, raw NaHA materials need to be processed; NaHA chains can be readily converted into smaller MW species via physical or chemical methods.…”