Germershaus, Oliver
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Germershaus, Oliver
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- PublikationApplication of natural and semi-synthetic polymers for the delivery of sensitive drugs(Taylor & Francis, 02/2015) Germershaus, Oliver; Lühmann, Tessa; Rybak, Jascha-Nikolai; Ritzer, Jennifer; Meinel, Lorenz [in: International Materials Reviews]Abstract This review summarises recent developments in the application of natural and semi-synthetic polymers for the delivery of sensitive drugs. Peptides, proteins and nucleic acids are drugs of increasing relevance potentially offering treatment options in indications with high unmet medical need. However, these drugs are characterised by high molecular weight, high sensitivity to enzymatic degradation, unfavourable pharmacokinetics and often require targetting to specific cell types or cellular compartments. To successfully transform these drug molecules into efficacious therapies, advanced drug delivery systems must be developed that protect the drug, control drug release to improve pharmacokinetics and allow efficient targetting. Synthetic, semi-synthetic or natural polymers or inorganic materials are frequently used for the development of drug delivery systems. Considering factors such as biocompatibility, biodegradability, solvent-free processing and availability from renewable resources, natural and semi-synthetic polymers are often advantageous compared to synthetic alternatives. On the other hand, material heterogeneity and purity of natural materials are concerns that need to be addressed. In this review, authors focus on frequently used biopolymers such as polysaccharides like chitosan and hyaluronan and proteins like silk fibroin (SF) and collagen and their semi-synthetic derivatives. Special emphasis will be put on material properties of such polymers rendering them suitable for drug delivery purposes and allow tight control to assure product quality and proper release characteristics. Natural polymers are frequently synthetically modified to alter or improve their characteristics. Such semi-synthetic derivatives and their advantages and disadvantages are critically discussed. Furthermore, the biocompatibility of natural materials and their derivatives is discussed.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationSimple and rapid high performance liquid chromatography method for the determination of polidocanol as bulk product and in pharmaceutical polymer matrices using charged aerosol detection(Elsevier, 02/2015) Ilko, David; Puhl, Sebastian; Meinel, Lorenz; Germershaus, Oliver; Holzgrabe, Ulrike [in: Journal of Pharmaceutical and Biomedical Analysis]Currently, neither the European nor the United States Pharmacopoeia provide a method for the determination of polidocanol (PD) content despite the fact that PD, besides being an excipient, is also used as an active pharmaceutical ingredient. We therefore developed a method where the PD content was determined using a Kinetex C18 column operated at 40°C with water-acetonitrile (15:85, v/v) as mobile phase. A Corona(®) charged aerosol detector was employed for the detection of PD that is lacking a suitable UV chromophore. The method was fully validated. Additionally, the method was applied for the determination of PD release from a pharmaceutical polymer matrix consisting of poly-ɛ-caprolactone and poly(lactic-co-glycolic acid) and PD.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationInfluence of salt type and ionic strength on self-assembly of dextran sulfate-ciprofloxacin nanoplexes(Elsevier, 2015) Kutscher, Marika; Cheow, Wean Sin; Werner, Vera; Lorenz, Udo; Ohlsen, Knut; Meinel, Lorenz; Hadinoto, Kunn; Germershaus, Oliver [in: International Journal of Pharmaceutics]We evaluated an analytical setup to identify optimal preparation conditions for nanoplex formation of small molecule drugs and polyelectrolytes using ciprofloxacin (CIP) and dextran sulfate (DS) as model compounds. The suitability of isothermal titration calorimetry (ITC) as a screening tool for rational formulation optimization was assessed. Besides ITC, static and dynamic light scattering, zeta potential measurements and scanning electron microscopy were applied to analyze the influence of different salt types and ionic strengths on CIP/DS nanoplex formation. The addition of low amounts of salt, especially 0.1M NaCl, improved the formation of CIP/DS nanoplexes. The presence of low amounts of salt led to smaller and more numerous particles of higher uniformity but had no influence on the release of CIP from nanoplexes. Furthermore, the molar range, within which efficient complexation was achieved, was broader in the presence of 0.1M NaCl than in the absence of salt with overall comparable complexation efficiency. Importantly, binding affinity correlated with particle shape and morphology, potentially enabling optimization of critical quality attributes based on ITC data. Altogether, ITC along with supplemental methods is a versatile screening tool for the evaluation of nanoplex formulation conditions regarding mixing ratio, salt type and ionic strength.01A - Beitrag in wissenschaftlicher Zeitschrift