Publications by authors named "Janine Griesser"
Hypothesis: Lysine based cationic surfactants are well-tolerated tools for hydrophobic ion pairing (HIP) with DNA and its incorporation into lipophilic delivery systems.
Experiments: Di-Boc-lysine was esterified with 1-hexadecanol and the Boc-residues were cleaved off resulting in hexadecyl lysinate (HL). Subsequently, its Log P and the critical micelle concentration (CMC) were determined.
Aim: It was the aim of the study to develop self-emulsifying drug delivery systems (SEDDS) with the ability to change their zeta potential towards higher values at the adsorption membrane and in this way facilitate the release of the DNA-cetrimonium complex and enhance transfection.
Methods: Plasmid DNA was complexed via hydrophobic ion pairing utilizing various surfactants and the complex was incorporated into SEDDS achieving a payload of 1% (m/v). Log P of the complex was determined.
Aim: The aim of the study was to develop self-emulsifying delivery systems (SEDDS) exhibiting improved permeation rate for pulmonary delivery of amikacin for treatment of cystic fibrosis (CF) patients.
Materials & Methods: Solubility of amikacin in lipids was improved by hydrophobic ion pairing with sodium myristyl sulfate. The complex was loaded into SEDDS.
Within the last decade, intensive research work has been conducted on thiolated hyaluronic acids (HA-SH). By attaching sulfhydryl ligands onto naturally occurring hyaluronic acid various types of HA-SH can be designed. Due the ability of disulfide bond formation within the polymer itself as well as with biological materials, certain properties such as mucoadhesive, gelling, enzyme inhibitory, permeation enhancing and release controlling properties are improved.
View Article and Find Full Text PDFAim: It was the aim of this study to evaluate the mucus permeating properties of self-emulsifying drug delivery systems (SEDDS) exhibiting different size and zeta potential.
Methods: Various SEDDS were prepared and characterized regarding droplet size, zeta potential and stability. Desmopressin was incorporated as model peptide drug and log P (SEDDS/water) was determined.
Aim: Aim of the study was the development of ζ potential changing nanoparticles as gene delivery system for the cystic fibrosis transmembrane conductance regulator gene.
Methods: Chitosan and carboxymethyl cellulose were modified with phosphotyrosine, a substrate for the brush border enzyme alkaline phosphatase. With these synthesized derivatives, different nanoparticle formulations, including the cystic fibrosis transmembrane conductance regulator gene were prepared by ionic gelation.
Aim: The aim of the study was to develop novel zeta potential changing self-emulsifying drug delivery systems (SEDDS) containing phosphorylated polysaccharides.
Methods: Starch and hydroxypropyl starch (HPS) were phosphorylated by utilizing phosphorus pentoxide. The modified starches, starch phosphate (SP) and hydroxypropyl starch phosphate (HPSP), were loaded into SEDDS and investigated regarding particle size, zeta potential, stability and cell viability.
Aim: Evaluation of inhibitory effect of emulsifiers on pancreatic trypsin and α-chymotrypsin.
Methods: The inhibitory effect of Cremophor EL, Cremophor RH 40, Brij O10, Tween 20, polyethylene glycol 8000, polyethylene glycol 400, Carbitol, Pemulen TR-1, Pemulen TR-2, Carbopol Ultrez 20 and Carbopol Ultrez 21 on pancreatic trypsin and α-chymotrypsin was tested. BAEE (Nα-Benzoyl-l-arginine ethyl ester), BTEE (N-Benzoyl-l-tyrosine ethyl ester), casein and insulin were used as substrates for trypsin and α-chymotrypsin.
Aim: The aim of this study was to evaluate the protective effect of self-emulsifying drug delivery systems (SEDDS) for therapeutic peptides towards intestinal proteases and reduced glutathione (GSH).
Methods: Sodium docusate was applied as anionic surfactant for hydrophobic ion pairing with leuprorelin (LEU), insulin (INS) and desmopressin (DES). The complexes were loaded into SEDDS that were characterized regarding droplet size distribution and zeta potential.
Purpose: The aim of the study was to create novel mucoadhesive drug delivery systems by incorporating amphiphilic hydrophobically modified, thiolated and preactivated polymers (preactivated thiomers) into self-emulsifying drug delivery systems (SEDDS).
Methods: L-Cysteine methyl ester was covalently attached to the polymeric backbone of Pemulen TR-2 and preactivated using 2-mercaptonicotinic acid (2-MNA). These thiomers were incorporated in a concentration of 0.
Aim: The aim of this study was the formation and characterization of various ion pairs of therapeutic peptides with different surfactants in order to reach a high payload in self-emulsifying drug delivering systems (SEDDS).
Methods: Hydrophobic ion pairs (HIP) were formed between the anionic surfactants sodium docusate, dodecylsulfate and oleate and the peptides leuprorelin (LEU), insulin (INS) and desmopressin (DES). The efficiency of HIP formation was evaluated by quantifying the amount of formed complexes, log P value determination in n-octanol/water via HPLC and zeta potential measurements.