Biodegradable poly(l-lactide)/calcium phosphate composites with improved properties for orthopedics: Effect of filler and polymer crystallinity.

Biodegradable poly(l-lactide)/calcium phosphate composites are promising materials for fabrication of bone fixation implants with improved properties. Multistage compounding was proposed as an efficient method for the preparation of biodegradable poly(l-lactide)/calcium phosphate composites with submicron filler dispersion and mechanical characteristics similar to native bone. The improvement of the characteristics is caused both by the filler itself and by the increase of polymer crystallinity due to the nucleation effect. The technique allows to fabricate biodegradable composites with controlled properties by varying concentration and type of the filler as well as degree of PLLA matrix crystallinity. Animal studies revealed that all the composites were biocompatible and non-toxic.

Atorvastatin calcium inclusion complexation with polysaccharide arabinogalactan and saponin disodium glycyrrhizate for increasing of solubility and bioavailability.

The aim of the present investigation was to enhance the solubility and dissolution of atorvastatin calcium (ATV), a poorly water-soluble drug with larch polysaccharide arabinogalactan (AG) and disodium glycyrrhizate (Na2GA) as carriers of drug delivery systems for improving its bioavailability. The interactions of ATV with AG or Na2GA were investigated by DSC, XRD, SEM, and NMR techniques. The molecular weights of supramolecular systems-inclusion complexes and micelles-which are the hosts for ATV molecules were measured. On the other hand, the rapid storage assay (+ 40 °C for 3 months) showed that the chemical stability of ATV/AG and ATV/Na2GA complexes had been enhanced compared with pure ATV. In vitro drug release showed a significant increase in ATV's dissolution rate after formation of a complex with Na2GA or AG. Pharmacokinetic tests in vivo on laboratory animals showed a significant increase in ATV's bioavailability after its introduction as a complex with Na2GA or AG. Moreover, ATV/AG and ATV/Na2GA complexes showed a more prominent decrease of total cholesterol (TC) level compared to net ATV. Therefore, the novel mechanochemically synthesized complexes of ATV with AG or Na2GA as drug delivery systems might be potential and promising candidates for hypercholesterolemia treatment and deserved further researches.

Preparation of curcumin self-micelle solid dispersion with enhanced bioavailability and cytotoxic activity by mechanochemistry.

An amorphous solid dispersion (SD) of curcumin (Cur) with disodium glycyrrhizin (Na2GA) was prepared by mechanical ball milling. Curcumin loaded micelles were self-formed by Na2GA when SD dissolved in water. The physical properties of Cur SD in solid state were characterized by differential scanning calorimetry, X-ray diffraction studies, and scanning electron microscope. The characteristics of the sample solutions were analyzed by reverse phase HPLC, UV-visible spectroscopy, 1H NMR spectroscopy, gel permeation LC, and transmission electron microscopy. In vitro cytotoxic tests demonstrated that Cur SD induced higher cytotoxicity against glioblastoma U-87 MG cells than free Cur. Besides, an improvement of membrane permeability of Cur SD was confirmed by parallel artificial membrane permeability assay. Further pharmacokinetic study of this SD formulation in rat showed a significant ∼19-fold increase of bioavailability as comparing to free Cur. Thus, Cur SD provide a more potent and efficacious formulation for Cur oral delivery.

Natural Products as a Source of Antiarrhythmic Drugs.

Throughout the development of medicine, the spotlight has been held by the search for new drugs blocking different types of arrhythmia. In the past decade, much attention was given to the selection of active antiarrhythmic substances from plant material. It has been shown that these compounds have a good antiarrhythmic effect, and their chemical modifications substantially increase their major effects while adding other beneficial pharmacological properties. In this regard, work on the chemical modification of plant-source antiarrhythmics is highly relevant to the development of new and promising drugs.

Enhanced solubility and bioavailability of simvastatin by mechanochemically obtained complexes.

In the present work, complexes of simvastatin (SIM) with polysaccharide arabinogalactan (AG) or disodium salt of glycyrrhizin acid (Na2GA) have been prepared using mechanochemical technique to improve the solubility of SIM and enhance its oral bioavailability. The interactions of SIM with AG or Na2GA were investigated by FTIR, DSC, XRD and SEM. Self-association of SIM in various solvents was investigated by UV/Vis and NMR techniques. The molecular masses of supramolecular systems-inclusion complexes and micelles, which are the "hosts" for SIM molecules were measured. The parallel artificial membrane permeability assay (PAMPA) revealed a strong increasing of SIM permeability in the presence of Na2GA in comparison with pure SIM used as a control. On the other hand, the rapid storage assay (+40°C for 3 months) showed that the chemical stability of SIM/AG complexes was similar to pure SIM, but SIM/Na2GA complexes had an enhanced stability. Pharmacokinetic tests in vivo on laboratory animals showed a significant increase in SIM's bioavailability after its introduction as a complex with Na2GA or AG. Moreover, SIM/AG inclusion complex performed better than SIM in reducing total cholesterol level. Therefore, the mechanochemically synthesized complexes of SIM with AG or Na2GA might have a promising future as novel formulations for hyper-cholesterolemia treatment.

Supramolecular Complex of Ibuprofen with Larch Polysaccharide Arabinogalactan: Studies on Bioavailability and Pharmacokinetics.

BACKGROUND AND OBJECTIVES: In the present work, pharmacological and pharmacokinetic properties of the supramolecular complex of non-steroid anti-inflammatory drug ibuprofen (IBU) with natural polysaccharide arabinogalactan (AG) were studied. The main goals of such complexation were the increase of ibuprofen's bioavailability and decrease its effective dose after oral administration. METHODS: The complex with mass ratio as IBU:AG 1:10 was obtained by mechanochemical synthesis and characterized by water solubility, electron microscopy, differential scanning calorimetry, X-ray powder diffraction analysis and 1H-nuclear magnetic resonance spectroscopy. Different animal models of pain and inflammation was used to investigate IBU:AG biological effects. Plasma concentration of IBU and its pharmacokinetic parameters were evaluated after oral introduction. RESULTS: It was found that ibuprofen's effective analgesic and anti-inflammatory dose decreased twofold after its introduction as a complex with AG. The reason of this difference is due to the increase of ibuprofen concentration in rats' plasma: C max of IBU at doses of 20 and 40 mg/kg was found as 0.088 and 0.132 µg/ml, whereas C max of IBU in the complex form was 0.103 and 0.160 µg/ml, respectively. CONCLUSIONS: Thus, we have shown that complexation of the IBU with AG results in its bioavailability increase, reduction of the effective dose and should decrease toxic side effects.

Improving the Efficiency and Safety of Aspirin by Complexation with the Natural Polysaccharide Arabinogalactan.

BACKGROUND: The main undesirable side effect of the aspirin is the damage to the gastrointestinal mucosa, leading to the formation of erosions, peptic ulcers, and as a result, bleeding. To overcome this problem "host-guest" complexation with natural polysaccharide arabinogalactan could be applied. METHODS: The complex with a weight ratio of ASA:AG = 1:10 was prepared by solid phase method in a rotary mill. Complex was administered orally to mice or rats at doses of 250, 500 or 1000 mg/kg. The "acetic acid induced writhing" and "hot plate" tests were used as an in vivo pain models. The antiinflammatory activity was studied using "histamine swelling" test. Also, long-term (30 days) oral introduction of the complex to rats was performed and gastric mucosa damages were evaluated. In all experiments pure aspirin (ASA) was used as a control in appropriate doses. RESULTS: The minimal effective analgesic dose of the complex was 250 mg/kg, equivalent to 23 mg/kg of ASA, a dose in which aspirin itself was not active. The anti-inflammatory effect was found at relatively higher doses: 500 and 1000 mg/kg (46 and 92 mg/kg of ASA respectively) for the complex and only at 100 mg/kg for the ASA. Long-term introduction of the complex at doses of 250 and 500 mg/kg was safe for gastric mucosa, while ASA at the dose of 50 mg/kg showed a strong gastric mucosal damage. CONCLUSION: The effective analgesic and anti-inflammatory doses of 1:10 aspirin complex with arabinogalactan are twice less compared to pure aspirin and safer for the gastrointestinal mucosa.

Effect of complexation with arabinogalactan on pharmacokinetics of "guest" drugs in rats: for example, warfarin.

A pharmacokinetic study of the warfarin (WF) : arabinogalactan (AG) complex with the 1 : 10 mass ratio after its intragastric introduction to Wistar rats at a dose of 5 mg/kg (WF dose in the complex was 0.5 mg/kg) once a day for three days was conducted. It was found that Cmax, T1/2, and AUC of WF in the complex form were lower than after the introduction of blank WF at the same dose, but its elimination (Cl, MRT) was much faster. Significant accumulation (C(min)) and an abrupt increase in plasma concentration after the third introduction were observed for blank WF, whereas the complex showed a much more moderate increase in concentration at this point. However, despite obvious differences in pharmacokinetic parameters, the efficacies of both agents were virtually identical; the complex differed from blank WF by only 15%. This value is rather insignificant and does not impair its anticoagulant activity. Thus, we can conclude that introduction of the WF : AG complex is safe in terms of reduction of the bleeding risk and accumulation.

Triterpenoid saponins from the roots of Acanthophyllum gypsophiloides Regel.

Two new triterpenoid saponins 1 and 2 were isolated from the methanol extract of the roots of Acanthophyllum gypsophiloides Regel. These saponins have quillaic acid or gypsogenin moieties as an aglycon, and both bear similar sets of two oligosaccharide chains, which are 3-O-linked to the triterpenoid part trisaccharide α-L-Arap-(1→3)-[α-D-Galp-(1→2)]-ß-D-GlcpA and pentasaccharide ß-D-Xylp-(1→3)-ß-D-Xylp-(1→3)-α-L-Rhap-(1→2)-[ß-D-Quip-(1→4)]-ß-D-Fucp connected through an ester linkage to C-28. The structures of the obtained saponins were elucidated by a combination of mass spectrometry and 2D NMR spectroscopy. A study of acute toxicity, hemolytic, anti-inflammatory, immunoadjuvant and antifungal activity was carried out. Both saponins 1 and 2 were shown to exhibit immunoadjuvant properties within the vaccine composition with keyhole limpet hemocyanin-based immunogen. The availability of saponins 1 and 2 as individual pure compounds from the extract of the roots of A. gypsophiloides makes it a prospective source of immunoactive agents.

Anti-inflammatory effect from indomethacin nanoparticles inhaled by male mice.

The respiratory system provides entry for drug nanoparticles to cure systemic diseases. The modern devices that are available on the market of therapeutic aerosol delivery systems have a number of disadvantages. There remains a need for an alternative means that is low cost, convenient, and capable of producing small-sized particles. On the other hand, one-third of the modern drugs are poorly water soluble. Many currently available injectable formulations of such drugs can cause side effects that originate from detergents and other agents used for their solubilization. The aerosol lung administration may by a good way for delivery of the water-insoluble drugs. We present here a new way for the generation of drug nanoparticles suitable for many water insoluble substances based on the evaporation-condensation route. In this paper the indomethacin nanoaerosol formation was studied and its anti-inflammatory effect to the outbred male mice was examined. The evaporation-condensation aerosol generator consisted of a horizontal cylindrical quartz tube with an outer heater. Argon flow was supplied to the inlet and the aerosol was formed at the outlet. The particle mean diameter and number concentration were varied in the ranges 3 to 200 nm and 10(3) to 10(7) cm(-3), respectively. The liquid chromatography and X-ray diffraction methods have shown the nanoparticles consist of the amorphous phase indomethacin. The aerosol lung administration experiments were carried out in the whole-body exposure chamber. Both the lung deposited dose and the particle deposition efficiency were determined as a function of the mean particle diameter for mice being housed into the nose-only exposure chambers. The anti-inflammatory action and side pulmonary effects caused by the inhalation of indomethacin nanoparticles were investigated. It was found that the aerosol administration was much more effective than the peroral treatment. The aerosol route required a therapeutic dose six orders of magnitude less than that for peroral administration.