Optimierte Partikelgrößencharakterisierung & orale Formulierungen

Titelblatt und Inhaltsverzeichnis Introduction Materials and Methods Laser diffractometry investigations on the method and on the performance of the LS 230 Determination of the real refractive index Cyclosporine nanosuspensions Zeta potential of nanosuspensions Further investigations of cyclosporine for oral delivery Summary Zusammenfassung References AppendixA more reliable laser diffractometer analytical procedure was developed to assess with higher accuracy the size of nanocrystals, the prerequisite for a sound formulation development. The screening procedure for optimised nanosuspension formulations was distinctly improved and the mechanism, leading to artefacts in the previous procedures, could be identified. A next generation approach for drug nanocrystals was realised by the SmartCrystal® technology, by combining nanocrystal technology with the inhibition strategy for p-glycoprotein. On top, an even simpler approach was realised by the development of the stabiliser free Cycloperls. In this formulation cyclosporine is dissolved in an oil with inhibitory effect on p-glycoprotein (peppermint oil), the oily solution is simply absorbed into porous Aeroperls. In this thesis two alternative cyclosporine formulations were developed SmartCrystals® and Cycloperls. The formulations are physically stable and should theoretically show an improved oral bioavailability, which should be proved in in vivo tests.In dieser Arbeit wurde die Partikelgrößencharakterisierung mittels Laserdiffraktometrie optimiert. Mit dieser optimierten Methodik ist es möglich, Partikelgrößen und Partikelgrößenverteilungen von Nanosuspensionen genauer und vor allem korrekt zu bestimmen. Nur mit Anwendung dieser hier etablierten Methode kann ein aussagekräftiges Ergebnis bei der Charakterisierung von Nanosuspensionen erzielt werden. Es konnte gezeigt werden, dass die herkömmliche Screening-Methode zur Identifizierung optimaler Stabilisatoren für Nanosuspensionen einige bisher nicht beachtete Fehlerquellen beinhaltet, die zu Artefakten führen können. Die Screening- Methode wurde dahingehend verbessert. Eine neue Generation von Nanokristallen wurde am Beispiel von Ciclosporin entwickelt, die SmartCrystal® Technologie. Diese Technologie beinhaltet die Vorteile einer Nanosuspension sowie die Fähigkeit, P-Glykoprotein zu hemmen. Eine weitere Formulierung mit Ciclosporin und zusätzlichen inhibitorischen Eigenschaften wurde mit den Cycloperls realisiert. Cycloperls bestehen nur aus Ciclosporin gelöst in Pfefferminzöl, absorbiert in Aeroperls 300. Sie enthalten keinen Emulgator. In dieser Arbeit konnten somit zwei alternative Ciclosporin-Formulierungen entwickelt werden SmartCrystals® und Cycloperls : zwei stabile Formulierungen, die theoretisch eine erhöhte orale Bioverfügbarkeit aufweisen, was nun in in vivo Studien getestet werden sollte

State of the art of nanocrystals – special features, production, nanotoxicology aspects and intracellular delivery

Drug nanocrystals are the latest, broadly introduced nanoparticulate carrier to the pharmaceutical market from the year 2000 onwards. The special features of nanocrystals for the delivery of poorly soluble drugs are briefly reviewed (saturation solubility, dissolution velocity, adhesiveness). The industrially relevant bottom up (precipitation) and top down production technologies (pearl milling, high pressure homogenization, combination technologies) are presented. As nanotoxicological aspects, the effect of size, degradability versus biopersistency and intracellular uptake are discussed, classifying the nanocrystals in the low/non-risk group. Intracellular uptake plays a minor or no role for dermal and oral nanocrystals, but it plays a key role for intravenously injected nanocrystals (e.g. nevirapine, paclitaxel, itraconazole). Uptake by the macrophages of the mononuclear phagocytic system (MPS, liver spleen) can modify/optimize blood profiles via prolonged release from the MPS (itraconazole), but also target toxicity by too high organ concentrations and thus cause nanotoxicity. The balance in the competitive intracellular uptake by MPS and the target cells (e.g. blood–brain barrier) decides about therapeutic efficiency. The concept of “differential protein adsorption” to modulate this balance is shown for its applicability to nanocrystals for intracellular delivery to the cells of the blood–brain barrier (atovaquone)

Long-Term Antibiotic Cost Savings from a Comprehensive Intervention Program in a Medical Department of a University-Affiliated Teaching Hospital

We tested a low-cost, multifaceted intervention program comprising formulary restriction measures, continued comprehensive education, and guidelines to improve in-hospital use of antibiotics and related costs. In a short-term analysis, total antibiotic consumption per patient admitted, which was expressed as defined daily doses (DDD), decreased by 36% (P < .001), and intravenous DDDs decreased by 46% (P < .01). Overall expenditures for antibiotic treatment decreased by 53% (US$100 per patient admitted). The 2 main cost-lowering factors were a reduction in prescription of antibiotics (35% fewer treatments; P < .0001) and more diligent use of 5 broad-spectrum antibiotics (23% vs. 10% of treatments; P = .001). Quality of care was not compromised. A pharmacy-based, prospective, long-term surveillance of DDDs and costs over 4 years showed an ongoing effect. This comprehensive intervention program, which aimed to reduce antibiotic consumption and costs, was highly successful and had long-lasting effect

PlantCrystals—Nanosized Plant Material for Improved Bioefficacy of Medical Plants

PlantCrystals are obtained by milling plant material to sizes < 10 µm. Due to the disruption of the plant cells, active compounds are easily released, rendering the PlantCrystal technology an effective and low-cost process for the production of environmentally friendly plant extracts. The extracts can be used to produce phytomedicines, nutritional supplements or cosmetic products. Previous studies could already demonstrate the use of PlantCrystals to improve the antimicrobial or antifungal activity of different plants. This study investigated whether PlantCrystal technology is suitable to produce plant derived formulations with high antioxidant capacity. The study also aimed to identify the most suitable production methods for this. Methods: Various plant materials and parts of plants, i.e., seeds, leaves and flowers, and different methods were employed for the production. PlantCrystals were characterized regarding size, physical stability and antioxidant capacity (AOC). Results: PlantCrystals with particles < 1 µm were produced from the different plant materials. Both production methods, i.e., high-pressure homogenization, bead milling or the combination of both were suitable to obtain PlantCrystals. Nano milling of the plant material greatly affected their AOC and resulted in formulations with distinctly higher AOC when compared to classical extracts. Conclusions: Rendering plant material into small sized particles is highly effective to obtain plant extracts with high biological efficacy

Rutin—Increased Antioxidant Activity and Skin Penetration by Nanocrystal Technology (smartCrystals)

Rutin is a well-known antioxidant from the group of flavonoids. Its use in cosmetic dermal products is, however, limited due to its poor water solubility. In order to increase rutin saturation solubility and improve the diffusion to the skin, rutin nanocrystals were produced by the smartCrystal process, e.g., bead milling followed by high pressure homogenization. Rutin nanocrystals were further incorporated into hydroxypropyl cellulose (HPC) gel and its long-term stability was assessed. Determination of the antioxidant activity was made by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay for these formulations: rutin nanocrystals (mean size 300 nm), rutin raw drug powder (mean size 33 μm) and commercial product. Furthermore, the skin penetration profile of rutin was investigated by the tape-stripping method on porcine skin. This study demonstrated that rutin nanocrystal gel had the highest neutralizing activity (90%), followed by a commercial product and rutin raw drug powder. According to the skin study, rutin nanocrystals penetrated to the deeper layers of the stratum corneum, the horny layer of the skin. View Full- Tex

Dynamic cultivation of human mesenchymal stem/stromal cells for the production of extracellular vesicles in a 3D bioreactor system

Purpose: 3D cell culture and hypoxia have been demonstrated to increase the therapeutic effects of mesenchymal stem/stromal cells (MSCs)-derived extracellular vesicles (EVs). In this study, a process for the production of MSC-EVs in a novel 3D bioreactor system under normoxic and hypoxic conditions was established and the resulting EVs were characterized. Methods: Human adipose-derived MSCs were seeded and cultured on a 3D membrane in the VITVO® bioreactor system for 7 days. Afterwards, MSC-EVs were isolated and characterized via fluorescence nanoparticle tracking analysis, flow cytometry with staining against annexin V (Anx5) as a marker for EVs exposing phosphatidylserine, as well as CD73 and CD90 as MSC surface markers. Results: Cultivation of MSC in the VITVO® bioreactor system demonstrated a higher concentration of MSC-EVs from the 3D bioreactor (9.1 × 109 ± 1.5 × 109 and 9.7 × 109 ± 3.1 × 109 particles/mL) compared to static 2D culture (4.2 × 109 ± 7.5 × 108 and 3.9 × 109 ± 3.0 × 108 particles/mL) under normoxic and hypoxic conditions, respectively. Also, the particle-to-protein ratio as a measure for the purity of EVs increased from 3.3 × 107 ± 1.1 × 107 particles/µg protein in 2D to 1.6 × 108 ± 8.3 × 106 particles/µg protein in 3D. Total MSC-EVs as well as CD73−CD90+ MSC-EVs were elevated in 2D normoxic conditions. The EV concentration and size did not differ significantly between normoxic and hypoxic conditions. Conclusion: The production of MSC-EVs in a 3D bioreactor system under hypoxic conditions resulted in increased EV concentration and purity. This system could be especially useful in screening culture conditions for the production of 3D-derived MSC-EVs

20 years of lipid nanoparticles (SLN & NLC): present state of development & industrial applications

In 1990, the lipid nanoparticles were invented in the laboratories, the first patent filings took place in 1991. The lipid nanoparticles were developed as alternative to traditional carriers such as polymeric nanoparticles and liposomes. After 20 years of lipid nanoparticles, the present state of development is reviewed - academic progress but also the development state of pharmaceutical products for the benefit of patients. Meanwhile many research groups are active worldwide, their results are reviewed which cover many different administration routes: dermal and mucosal, oral, intravenous/ parenteral, pulmonary but also ocular. The lipid nanoparticles are also used for peptide/protein delivery, in gene therapy and various miscellaneous applications (e.g. vaccines). The questions of large scale production ability, accepted regulatory status of excipients, and - important for the public perception - lack of nanotoxicity are discussed, important pre-requisites for the use of each nanocarrier in products. Identical to the liposomes, the lipid nanoparticles entered first the cosmetic market, product examples are presented. Presently the pharmaceutical product development focuses on products for unmet needs and on niche products with lower development costs (e.g. ocular delivery), which can be realized also by smaller companies. A pharmaceutical perspective for the future is given, but also outlined the opportunities for non-pharmaceutical use, e.g. in nutraceuticals

Resuspendable Powders of Lyophilized Chalcogen Particles with Activity against Microorganisms

Many organic sulfur, selenium and tellurium compounds show considerable activity against microorganisms, including bacteria and fungi. This pronounced activity is often due to the specific, oxidizing redox behavior of the chalcogen-chalcogen bond present in such molecules. Interestingly, similar chalcogen-chalcogen motifs are also found in the elemental forms of these elements, and while those materials are insoluble in aqueous media, it has recently been possible to unlock their biological activities using naturally produced or homogenized suspensions of respective chalcogen nanoparticles. Those suspensions can be employed readily and often effectively against common pathogenic microorganisms, still their practical uses are limited as such suspensions are difficult to transport, store and apply. Using mannitol as stabilizer, it is now possible to lyophilize such suspensions to produce solid forms of the nanoparticles, which upon resuspension in water essentially retain their initial size and exhibit considerable biological activity. The sequence of Nanosizing, Lyophilization and Resuspension (NaLyRe) eventually provides access to a range of lyophilized materials which may be considered as easy-to-handle, ready-to-use and at the same time as bioavailable, active forms of otherwise insoluble or sparingly substances. In the case of elemental sulfur, selenium and tellurium, this approach promises wider practical applications, for instance in the medical or agricultural arena

Natural Nanoparticles: A Particular Matter Inspired by Nature

During the last couple of decades, the rapidly advancing field of nanotechnology has produced a wide palette of nanomaterials, most of which are considered as “synthetic” and, among the wider public, are often met with a certain suspicion. Despite the technological sophistication behind many of these materials, “nano” does not always equate with “artificial”. Indeed, nature itself is an excellent nanotechnologist. It provides us with a range of fine particles, from inorganic ash, soot, sulfur and mineral particles found in the air or in wells, to sulfur and selenium nanoparticles produced by many bacteria and yeasts. These nanomaterials are entirely natural, and, not surprisingly, there is a growing interest in the development of natural nanoproducts, for instance in the emerging fields of phyto- and phyco-nanotechnology. This review will highlight some of the most recent—and sometimes unexpected—advances in this exciting and diverse field of research and development. Naturally occurring nanomaterials, artificially produced nanomaterials of natural products as well as naturally occurring or produced nanomaterials of natural products all show their own, particular chemical and physical properties, biological activities and promise for applications, especially in the fields of medicine, nutrition, cosmetics and agriculture. In the future, such natural nanoparticles will not only stimulate research and add a greener outlook to a traditionally high-tech field, they will also provide solutions—pardon—suspensions for a range of problems. Here, we may anticipate specific biogenic factories, valuable new materials based on waste, the effective removal of contaminants as part of nano-bioremediation, and the conversion of poorly soluble substances and materials to biologically available forms for practical use

Polyhydroxy surfactants for the formulation of lipid nanoparticles (SLN and NLC): Effects on size, physical stability and particle matrix structure

The two polyhydroxy surfactants polyglycerol 6-distearate (Plurol (R) Stearique WL1009 - (PS)) and caprylyl/capryl glucoside (Plantacare (R) 810 - (PL)) are a class of PEG-free stabilizers, made from renewable resources. They were investigated for stabilization of aqueous solid lipid nanoparticle (SIN) and nanostructured lipid carrier (NLC) dispersions. Production was performed by high pressure homogenization, analysis by photon correlation spectroscopy (PCS), laser diffraction (LD), zeta potential measurements and differential scanning calorimetry (DSC). Particles were made from Cutina CP as solid lipid only (SIN) and its blends with Miglyol 812 (NLC, the blends containing increasing amounts of oil from 20% to 60%). The obtained particle sizes were identical for both surfactants, about 200 nm with polydispersity indices below 0.20 (PCS), and unimodal size distribution (ID). All dispersions with both surfactants were physically stable for 3 months at room temperature, but Plantacare (PL) showing a superior stability. The melting behaviour and crystallinity of bulk lipids/lipid blends were compared to the nanoparticles. Both were lower for the nanoparticles. The crystallinity of dispersions stabilized with PS was higher, the zeta potential decreased with storage time associated with this higher crystallinity, and leading to a few, but negligible larger particles. The lower crystallinity particles stabilized with PL remained unchanged in zeta potential (about -50 mV) and in size. These data show that surfactants have a distinct influence on the particle matrix struture (and related stability and drug loading), to which too little attention was given by now. Despite being from the same surfactant class, the differences on the structure are pronounced. They are attributed to the hydrophobic-lipophilic tail structure with one-point anchoring in the interface (PL), and the loop conformation of PS with two hydrophobic anchor points, i.e. their molecular structure and its interaction with the matrix surface and matrix bulk. Analysis of the effects of the surfactants on the particle matrix structure could potentially be used to further optimization of stability, drug loading and may be drug release