Skeletal muscle uncoupling-induced longevity in mice is linked to increased substrate metabolism and induction of the endogenous antioxidant defense system.

Ectopic expression of uncoupling protein 1 (UCP1) in skeletal muscle (SM) mitochondria increases lifespan considerably in high-fat diet-fed UCP1 Tg mice compared with wild types (WT). To clarify the underlying mechanisms, we investigated substrate metabolism as well as oxidative stress damage and antioxidant defense in SM of low-fat- and high-fat-fed mice. Tg mice showed an increased protein expression of phosphorylated AMP-activated protein kinase, markers of lipid turnover (p-ACC, FAT/CD36), and an increased SM ex vivo fatty acid oxidation. Surprisingly, UCP1 Tg mice showed elevated lipid peroxidative protein modifications with no changes in glycoxidation or direct protein oxidation. This was paralleled by an induction of catalase and superoxide dismutase activity, an increased redox signaling (MAPK signaling pathway), and increased expression of stress-protective heat shock protein 25. We conclude that increased skeletal muscle mitochondrial uncoupling in vivo does not reduce the oxidative stress status in the muscle cell. Moreover, it increases lipid metabolism and reactive lipid-derived carbonyls. This stress induction in turn increases the endogenous antioxidant defense system and redox signaling. Altogether, our data argue for an adaptive role of reactive species as essential signaling molecules for health and longevity.

Polyacrylic acid/polyvinylpyrrolidone bipolymeric systems. I. Rheological and mucoadhesive properties of formulations potentially useful for the treatment of dry-eye-syndrome.

For the treatment of dry-eye-syndrome preparations containing polymers as active agents are used. Polyacrylic acid (PAA) is a well known mucoadhesive polymer. For ocular use, however, the very high viscous gel systems can cause irritation post application which can result in a low patient compliance. In this study we have shown that it is possible to formulate PAA based low viscous formulations with polyvinylpyrrolidone (PVP) as 2nd polymer. The survey of the systems for the parameters microviscosity with polarization and oscillatory rheology shows that the 2nd polymer influences the structure of the PAA gel framework that causes the significant decrease in apparent viscosity of the combination. The mucoadhesion and rheological characteristics were determined by means of rheological methods. The acquired results, low viscosity and a high mucoadhesion index in comparison with the monopolymer PAA preparation and with two PAA containing commercial artificial tear preparations, Vidisic and Thilo Tears, led to the conclusion that the combination of the two polymers, PAA and PVP, could be advantageous for the treatment of the dry eye.

Effects of microemulsions on the stratum corneum and hydrocortisone penetration.

We tested a high-water-content hydrophilic microemulsion (ME 1) and a low-water-content lipophilic microemulsion (ME 2) for their suitability for use in dermatology, in general, and as alternative hydrocortisone (HC) vehicles, in particular. The lipophilic component of both study products was isopropyl myristate. The surfactant/cosurfactant system of ME 1 consisted of two sucrose esters and that of ME 2 was a mixture of Tagat S and Plurololeat. Both MEs showed no in vitro irritability in the hen's egg test on chorioallantoic membranes. In 14 subjects, stratum corneum water content was determined by corneometry and transepidermal water loss (TEWL) by the Tewameter before and after 3 days use of ME 1 or ME 2 as well as on two untreated control sites. ME 1 produced dehydration and increased TEWL as evidence of barrier compromise. ME 2 also produced an increase in TEWL but had no dehydrating effect. Subjects then underwent standardized washing with a surfactant solution. Under these conditions, pretreatment with ME 2 also produced dehydration, but to a lesser extent than did pretreatment with ME 1. In the same subjects, the impact of the two MEs on HC penetration (0.5%, 24h occlusion) was evaluated in terms of the chromameter-determined blanching effect compared with that on a site treated only with an occlusive film dressing. The comparator was an ambiphilic cream (Basiscreme (BC) Deutscher Arzneimittel Codex (German Formulary)). Irritative skin redness produced by ME 1 was significant and that produced by ME 2 was slight but visible, compared with BC. HC penetration was demonstrable from all the study products via the blanching effect and was significantly greater from ME 1 and slightly greater from ME 2 than from BC. However, neither ME would improve HC therapy because the irritative effects were so great that the blanching effect of HC formulated in ME 1 was significantly smaller and that of HC in ME 2 slightly smaller than that of HC formulated in BC.

Influence of alpha-cyclodextrin and hydroxyalkylated beta-cyclodextrin derivatives on the in vitro corneal uptake and permeation of aqueous pilocarpine-HCl solutions.

Interactions in aqueous solution between pilocarpine hydrochloride (P-HCl), a rather hydrophilic drug with good water solubility, and various cyclodextrins (CDs) were described recently. To assess the influence of CDs on the diffusion behavior of pilocarpine, in vitro studies were performed using porcine or bovine corneas as diffusion barriers. The affinity of P-HCl for porcine cornea in the presence of alpha-cyclodextrin (alpha-CD) and (hydroxyethyl)-beta-cyclodextrin (HE-beta-CD) was determined by drug uptake experiments. Additionally, in vitro permeation experiments through bovine corneas were conducted with a modified diffusion device optimized for corneal perfusion studies. The results obtained from the corneal uptake studies indicate that the addition of alpha-CD led to increased tissue drug levels. The increase in permeability of pilocarpine in the presence of alpha-CD was approximately 10-fold (log Papp = -4.87 +/- 0.03) in comparison with plain P-HCl solution (log Papp = -5.89 +/- 0.06). Permeation studies with corneas pretreated with alpha-CD solution revealed enhanced corneal permeability of pilocarpine due to alpha-CD induced membrane effects. The hydroxyalkylated beta-CD derivatives HE-beta-CD (log Papp = -6.27 +/- 0.09) and (hydroxypropyl)-beta-cyclodextrin (HP-beta-CD; log Papp = -6.40 +/- 0.03), however, seemed to cause slightly decreased permeation rates, supporting the concept of an interaction between pilocarpine and the hydroxyalkylated-beta-CD derivatives. Considering physiological compatibility, the addition of CDs seems to be an effective tool to modify and optimize the ocular availability of pilocarpine.

Influence of cyclodextrins on the in vitro corneal permeability and in vivo ocular distribution of thalidomide.

The aim of the present study has been to develop aqueous Thalidomide (THA) eye drops in order to minimize systemic side effects and to improve bioavailability following topical application. Cyclodextrins (CDs), suitable vehicles to improve aqueous solubility of THA, were evaluated with regard to their ability to influence in vitro corneal permeability of THA. Additionally, rabbit eyes received either THA-suspension (0.04%) (THA-SP) or THA (0.04%)/hydroxypropyl-beta-cyclodextrin (HP-beta-CD) (12.5%) solution (THA-CD). In vitro corneal permeation studies demonstrated that the absolute amount of THA permeated could not be increased by means of CDs. The percentile release of THA was extensively decreased using saturated THA/CD solutions. Following loading doses of either THA-CD or THA-SP onto the rabbit eye, significantly increased aqueous humor levels were obtained for THA-CD 30 min (THA-CD:THA-SP=4.6:1) and 60 min (THA-CD:THA-SP=3.1:1) post instillation (p<0.05). In the iris-ciliary body, significantly increased THA levels were obtained using THA suspension (THA-CD(60 min):THA-SP(60 min)=1:6.1) (p<0.05). In the cornea, conjunctiva, vitreous and sclera, differences between the THA tissue levels were not statistically significant. Cyclodextrins might be a useful tool to formulate aqueous THA eye drop solutions and modify intraocular drug bioavailability.

[Transcorneal-paracorneal penetration route for topical application of drugs to the eyt. Mycophenolate mofetil as a model substance]. / Transkornealer-parakornealer Penetrationsweg für lokal applizierte Pharmaka am AugeMycophenolat Mofetil als Modellsubstanz.

PURPOSE: Topically applied drugs can penetrate transcorneally or paracorneally (transsclerally). There are only few studies to demonstrate the relationship of both penetration routes. The immuno-modulator mycophenolate mofetil (MMF), ester and pro-drug of mycophenolic acid (MPA), is a promising substance for such studies. MATERIAL AND METHODS: Rabbit eyes were treated with different preparations of MMF as a cyclodextrin complex (MM-CD) and as a suspension (MMF-SP) and MPA as a cyclodextrin complex (MPA-CD). The concentrations of both compounds were measured in the cornea, conjunctiva, aqueous humor, vitreous body and iris-ciliary body. RESULTS: Only MPA is detectable in the cornea after application of MMF-CD and MMF-SP. In the aqueous humor high concentrations of MPA are detectable after 60 min. In the iris-ciliary body both MMF and MPA can be found. CONCLUSION: The intraocularly detected mycophenolate mofetil represents the paracorneally penetrated fraction. After topical application of mycophenolate mofetil in suitable preparations high concentrations of the active substance can be achieved intraocularly. These favourable pharmacokinetic characteristics are promising for new therapeutic strategies in immune-mediated diseases of the anterior part of the eye.

[On the dropping behaviour of drug solutions (author's transl)]. / Zum Tropfverhalten von Arzneilösungen.

On testing a preferentially inserted dropping device (marginal-dispensing dropper) of high-pressure process-polyethylene, the authors stated irregular dropping which impaired the dosing of ethanolic-aqueous drug solutions. The addition of macromolecular viscosity-increasing agents (0.2 or 0.3% of hydroxyethylcellulose and 0.5% of methyl cellulose being very suited) permitted to obtain a sequence of uniform easy-to-count drops and to reduce the amount of variation in the individual drop masses. Manufacturing differences among the dropping devices are a substantial source of error which might be reduced by fully automatic control. An improvement in the dropping behaviour of the dropping device under investigation can be expected from suggestions for changes in its design. The use of a "general purpose dropping device" is inconsistent with the specific properties of the drug preparations. Dosing accuracy is higher with central-dispensing droppers than with marginal-dispensing ones.

[Interaction between macromolecular adjuvants and drugs. 25. The effect of cellulose ether on the solubility characteristics of benzodiazepine derivatives]. / Wechselwirkungen zwischen makromolekularen Hilfsstoffen und Arzneistoffen. 25. Mitteilung: Zur Beeinflussung der Auflösungscharakteristika von Benzodiazepinderivaten durch Celluloseether.

The technological processing of the benzodiazepine derivatives chlordiazepoxide, medazepam, diazepam, nitrazepam and clonazepam with methyl cellulose (mc) and hydroxyethylcellulose--especially physical mixtures and evaporates--led to an improved dissolution of the problem drugs. The effect of the adjuvants is remarkable in the initial phase of the dissolution and very distinctive at the end of the experiment. Obviously there is no relation between saturation solubility and dissolution. Only with nitrazepam and clonazepam, but less clearly with medazepam, an increase of solubility by the mc-trituration was observed. Studies of the binding showed a concentration and temperature dependent interaction of the benzodiazepines diazepam, clonazepam, medazepam and nitrazepam, to mc. As X-ray diffraction and differential thermoanalysis gave no interpretation for the improved dissolution behaviour of drug/adjuvant preparations, it is assumed that a high distribution of the drug particles in the dissolution medium by the preceding treatment with cellulose ether is the main reason for the increase of the dissolution rate.

[Interaction between macromolecular adjuvants and drugs. 24. Improvement of the solubility characteristics of benzodiazepine derivatives with polyvinylpyrrolidone]. / Wechselwirkungen zwischen makromolekularen Hilfsstoffen und Arzneistoffen. 24. Mitteilung: Zur Verbesserung der Auflösungscharakteristika von Benzodiazepinderivaten durch Polyvinylpyrrolidon.

Solubility and dissolution rate of the benzodiazepine derivatives chlordiazepoxide, diazepam, medazepam, nitrazepam and clonazepam has been improved by adding polyvinylpyrrolidone (PVP K 30). Increasing concentrations of the carrier as well as the preparation of coprecipitates usually supported the effect (less physical mixtures). Regarding to the dissolution PVP has a positive effect on the initial phase of dissolution particularly. Under the experimental conditions described an interaction between drugs and carrier was revealed increasing with the concentration of PVP. These interactions were of endothermic character. Connections between dissolution and binding results were evident. Differential thermal analysis and x-ray diffractometric studies probably refer to a partial amorphous form of the drugs, especially in coprecipitates with a higher concentration of PVP.

Physico-chemical, in vitro and in vivo characterisation of polymers for ocular use.

The influence of artificial tear fluid (AT) on ionic and nonionic ophthalmic polymer excipients was rheologically established. In usual concentrations polyvinylalcohol, polyvinylpyrrolidone, dextran, hydroxypropylmethylcellulose, hydroxyethylcellulose and methylcellulose did not show any changes. In contrast, solutions of polyacrylic acid, sodium hyaluronate (S-Hya), sodium alginate (S-Alg) and chitosan decrease the apparent viscosity in contact with AT, while gellan solution increases the viscosity and shows thixotropy. The adhesion of selected polymers (polysaccharides) on mucin was evaluated using a rheological method and resulted in the order S-Hya > Gellan > S-Alg > dextran. Miosis testing of Gellan containing pilocarpine HCl formulations in rabbits shows a possible reduction of drug concentration from 2% to 0.5% obtaining the same bioavailability.

[Interactions between macromolecular adjuvants and drugs. Part 18: The binding behaviour of sodium carboxymethylcellulose and other macromolecules towards streptomycin sulphate (author's transl)]. / Wechselwirkungen zwischen makromolekularen Hilfsstoffen und Arzneistoffen. 18. Mitteilung: Bindungsverhalten von Natriumcarboxymethylcellulose und anderen Makromolekülen gegenüber Streptomycinsulfat.

Unlike the other macromolecules under investigation (polyvinylpyrrolidone, methylcellulose, polyvinyl alcohol), sodium carboxymethylcellulose acts on streptomycin sulphate, which leads to isolable precipitates. By equilibrium dialysis in electrolyte-free and electrolyte-containing solutions, the interaction was characterized in more detail and described by Donnan curves. The associates (which contained, on an average, 40% of streptomycin) proved to be resistant to light and air, and stable to thin-layer chromatography. Microbiological assays on the test strain Bacillus subtilis SG119 revealed a decrease in activity of the streptomycin-sodium carboxymethylcellulose associates compared to pure streptomycin (tested in the solid form, using rice granulate as a carrier substance). In contrast, the associate was as efficient as the antibiotic when dissolved in a concentrated solution of sodium chloride.

[Antiglaucoma ophthalmic agents with prolonged action based on macromolecular excipients. 1. In vitro studies]. / Antiglaukomatosahaltige Ophthalmika mit prolongierter Wirkung auf Basis makromolekularer Hilfsstoffe. Teil 1: In vitro-Untersuchungen.

Hydrogels and Hydrosols based on sodium carboxymethyl-cellulose (NaCMC), polyvinylpyrrolidone (PVP) and polyacrylic acids (PAS) Carbopol 940, Scopacryl D 339 (PAS-B) and PAS-Fluka (PAS-F) were investigated in vitro for rheological properties and pilocarpine release. The gels showed diffusion coefficients in the series Carbopol 940 1% greater than NaCMC 3% greater than PAS-F 3.5% greater than PVP K 90 23% greater than PAS-B 8% greater than PAS-F 7%. Especially PAS-F proved suitable for prolonged release, also in liquid preparations. Lyophilizated pilocarpine polymer-salts which were prepared from PAS-F and pilocarpine base, both in effect of retardation and in drug stability showed important advantages compared with aqueous solution of pilocarpine.

[Preparations of preoral sustained-release preparations with a biological polymer base. 5 (correct title supplied from Table of Contents)]. / Darstellung peroral Retardarzneiformen auf der Basis von biologisch abbaubaren Polymeren. 5. Mitteilung [correct title supplied from Table of Contents]

Triethylamine and chloroacetic acid were used for the preparation of polyglycolic acid. The polyester was characterized by elementary analysis, IR-spectroscopy, X-ray-test and the determination of the molecular mass. With regard to the pharmaceutical and technological characterization the determination of the grain size, moisture content, flowability and the parameters for the direct compression were carried out. Polyglycolic acid was compressed together with caffeine as model drug. These tablets distinguished by a great strength, but in water a rapid decay took place. A greater stability in artificial gastrointestinal fluids was obtained, if the tablets were plastified. Release investigations showed then the desired retard effect.

[Antiglaucoma ophthalmic agents with prolonged action with based on macromolecular excipients. 3. Optimized drop preparation on a polyacrylate base]. / Antiglaukomatosahaltige Ophthalmika mit prolongierter Wirkung auf Basis makromolekularer Hilfsstoffe. Teil 3: Optimierte, tropfbare Rezepturen auf Polyacrylatbasis.

In contrast to the standardized product Carbopol 940, polyacrylic acid-Fluka (PAS-F, a copolymerized product of acrylic and methacrylic acid) can form liquid preparations, which have weak acid pH values from 5.3 to 6.5. Such pH-values are euhydric pH-values of many medical substances. Different PAS-F-preparations were developed and their physical-chemical parameters were characterized. 3.5% PAS-F and pilocarpine or carbachol containing preparations have suitable viscosities from 18 to 72mPa.s. According to in vitro tests, these preparations showed a significantly prolonged release of the drugs compared to the aqueous solutions. In human tests, the physiological compatibility of PAS-F-preparation was proved and the drug action was prolonged as well as the drug intensity was increased compared to the aqueous solutions of drugs.

[Comparative studies on the study of drug-excipient interactions with vapor pressure osmometry and equilibrium dialysis]. / Vergleichende Untersuchungen zur Erfassbarkeit von Arzneistoff-Hilfsstoff Wechselwirkungen mittels Dampfdruckosmometrie und Gleichgewichtsdialyse.

The authors discuss how far the vapour osmometry enables to make statements on the interaction between drugs and macromolecular agents as well as on their dependence upon various test parameters. The results are compared to those of the equilibrium dialysis. Sulfathiazole sodium and the polyvinylpyrrolidones PVP K 25 and PVP K 90 are used the sample substances. Concerning the interaction dependence upon the concentrations of drugs or agents, resp., both the methods revealed findings of comparable trends. An increased agent concentration or a reduced drug concentration results in an increased sulfathiazole-PVP interaction. An exothermic binding process can be derived from tonometric and dialysis results. Vapour osmometric measurements not only restricting to the interactions drugs-agents, but also recording all the interactions caused by variations of the particle number, the findings obtained by means of buffered solution do not permit a comparability of both the methods. Although the equilibrium dialysis takes precedence in the exact registration of drug-agent interactions, the vapour osmometry has an advantage in the registration of drug interactions with membrane-permeating agents.

[Antiglaucoma ophthalmic agents with prolonged action based on macromolecular excipients. 2. In vivo studies]. / Antiglaukomatosahltige Ophthalmika mit prolongierter Wirkung auf Basis makromolekularer Hilfsstoffe. Teil 2: In vivo-Untersuchungen.

The prolonged in vitro release of pilocarpine (1) from preparations containing polyacrylic acids were represented consecutively . A preparation of polyacrylic acid-F (PAS-F; an acrylic-methacrylic acid copolymer) does not irritate the eyes. According to miotic activity tests in rabbits, the activity is prolonged by PAS-F as well as Carbopol 940 preparations. Differences between the compared preparations are not obtained. In human studies, the 1 action is prolonged and the intensity is increased by PAS-F and Carbopol containing preparations compared with aqueous 1 solution (relative bioavailability about 200%; the duration of the intraocular pressure is 4.5 times in the therapeutical relevant level). A polymeric salt of 1 and PAS-F was particular suitable in this study.