ABSTRACT
The standard treatment of intoxication with organophosphorus (OP) compounds includes the administration of oximes acting as acetylcholinesterase (AChE) reactivating antidotes. However, the blood-brain barrier (BBB) restricts the rapid transport of these drugs from the blood into the brain in therapeutically relevant concentrations. Since human serum albumin (HSA) nanoparticles enable the delivery of a variety of drugs across the BBB into the brain, HI 6 dimethanesulfonate and HI 6 dichloride monohydrate were bound to these nanoparticles in the present study. The resulting sorption isotherms showed a better fit to Freundlich's empirical adsorption isotherm than to Langmuir's adsorption isotherm. At the pH of 8.3 maximum drug binding capacities of 344.8 µg and 322.6 µg per mg of nanoparticles were calculated for HI 6 dimethanesulfonate and HI 6 dichloride monohydrate, respectively. These calculated values are higher than the adsorption capacity of 93.5 µg/mg for obidoxime onto HSA nanoparticles determined in a previous study. In vitro testing of the nanoparticulate oxime formulations in primary porcine brain capillary endothelial cells (pBCEC) demonstrated an up to two times higher reactivation of OP-inhibited AChE than the free oximes. These findings show that nanoparticles made of HSA may enable a sufficient antidote OP-poisoning therapy with HI 6 derivatives even within the central nervous system (CNS).
Subject(s)
Antidotes , Blood-Brain Barrier/metabolism , Drug Carriers/chemistry , Nanoparticles/chemistry , Oximes , Pyridinium Compounds , Serum Albumin/chemistry , Animals , Antidotes/administration & dosage , Antidotes/chemistry , Antidotes/pharmacokinetics , Biological Transport , Brain/blood supply , Brain/cytology , Capillaries/cytology , Capillaries/metabolism , Cell Membrane/metabolism , Cells, Cultured , Drug Compounding , Drug Design , Endothelial Cells/metabolism , Endothelium, Vascular/cytology , Endothelium, Vascular/metabolism , Humans , Models, Chemical , Oximes/administration & dosage , Oximes/chemistry , Oximes/pharmacokinetics , Particle Size , Pyridinium Compounds/administration & dosage , Pyridinium Compounds/chemistry , Pyridinium Compounds/pharmacokinetics , SwineABSTRACT
Nanoparticles consisting of human serum albumin (HSA) play an emerging role in the development of new drug delivery systems. Many of these protein-based colloidal carriers are prepared by the well-known desolvation technique, which has shown to be a robust and reproducible method for the laboratory-scale production of HSA nanoparticles. The aim of the present study was to upscale the ethanolic desolvation process utilizing the paddle stirring systems Nanopaddle I and II in combination with a HPLC pump in order to find the optimal conditions for the controlled desolvation of up to 2000 mg of the protein. For characterization of the HSA nanoparticles particle size, zeta potential as a function of the pH, polydispersity index and particle content were investigated. The particle content was determined by microgravimetry and by a turbidimetry to allow optimized in-process control for the novel desolvation technique. Furthermore the sedimentation coefficient was measured by analytical ultracentrifugation (AUC) to gain deeper insight into the size distribution of the nanoparticles. The formed nanocarriers were freeze dryed to achieve a solid preparation for long-term storage and further processing. Particles ranging in size between 251.2 ± 27.0 and 234.1 ± 1.5 nm and with a polydispersity index below 0.2 were achieved.
Subject(s)
Drug Carriers/chemistry , Drug Compounding/methods , Drug Delivery Systems , Nanoparticles/chemistry , Serum Albumin/chemistry , Drug Carriers/analysis , Drug Discovery , Ethanol/chemistry , Excipients/chemistry , Freeze Drying , Humans , Molecular Weight , Nanoparticles/analysis , Particle Size , Serum Albumin/analysis , Serum Albumin/metabolism , Solubility , Surface PropertiesABSTRACT
BACKGROUND: Due to the use of organophosphates (OP) as pesticides and the availability of OP-type nerve agents, an effective medical treatment for OP poisonings is still a challenging problem. The acute toxicity of an OP poisoning is mainly due to the inhibition of acetylcholinesterase (AChE) in the peripheral and central nervous systems (CNS). This results in an increase in the synaptic concentration of the neurotransmitter acetylcholine, overstimulation of cholinergic receptors and disorder of numerous body functions up to death. The standard treatment of OP poisoning includes a combination of a muscarinic antagonist and an AChE reactivator (oxime). However, these oximes can not cross the blood-brain barrier (BBB) sufficiently. Therefore, new strategies are needed to transport oximes over the BBB. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we combined different oximes (obidoxime dichloride and two different HI 6 salts, HI 6 dichloride monohydrate and HI 6 dimethanesulfonate) with human serum albumin nanoparticles and could show an oxime transport over an in vitro BBB model. In general, the nanoparticulate transported oximes achieved a better reactivation of OP-inhibited AChE than free oximes. CONCLUSIONS/SIGNIFICANCE: With these nanoparticles, for the first time, a tool exists that could enable a transport of oximes over the BBB. This is very important for survival after severe OP intoxication. Therefore, these nanoparticulate formulations are promising formulations for the treatment of the peripheral and the CNS after OP poisoning.
Subject(s)
Blood-Brain Barrier , Nanotechnology/methods , Oximes/chemistry , Pyridinium Compounds/pharmacology , Acetylcholine/chemistry , Acetylcholinesterase/metabolism , Animals , Cholinesterase Inhibitors/pharmacology , Cholinesterase Reactivators/pharmacology , Humans , In Vitro Techniques , Mice , Nanoparticles/chemistry , Organophosphates/chemistry , Oximes/pharmacology , Serum Albumin/chemistry , SwineABSTRACT
Intoxication with organophosphorous nerve agents such as paraoxon requires immediate administration of antidotes such as oximes. However, the oximes lack sufficient activity in the central nervous system as they are unable to rapidly penetrate the blood-brain barrier (BBB) in therapeutically relevant concentrations. Human serum albumin (HSA) nanoparticles represent a promising drug carrier system for the transport of drugs across the BBB. This study focussed on the development of an obidoxime-loaded nanoparticles prepared by desolvation using an incorporation technique. The nanoparticle preparation parameters, i.e. drug amount, pH value, ethanol volume and crosslinking degree, were optimised. The in vitro release study showed a sustained release profile, indicating the suitability of the developed formulation for the transport of oximes across the BBB.
Subject(s)
Chemistry, Pharmaceutical/methods , Drug Carriers/chemistry , Drug Delivery Systems/methods , Nanoparticles/chemistry , Obidoxime Chloride/chemistry , Serum Albumin/chemistry , Cross-Linking Reagents/chemistry , Cross-Linking Reagents/pharmacology , Drug Carriers/pharmacology , Drug Compounding , Drug Stability , Ethanol/chemistry , Ethanol/pharmacology , Humans , Hydrogen-Ion Concentration , Obidoxime Chloride/pharmacology , Serum Albumin/pharmacology , Temperature , Time FactorsABSTRACT
The standard treatment of poisoning by organophosphorous compounds such as paraoxon includes the administration of oximes. Due to their inability to rapidly cross the blood-brain barrier (BBB) in therapeutically relevant concentrations, these drugs possess insufficient activity in the central nervous system. Since human serum albumin (HSA) nanoparticles enable the delivery of a variety of drugs across the BBB into the brain, in the present study the antidote obidoxime was bound to these particles by adsorption. The resulting sorption isotherms showed a best fit to Langmuir isotherms indicating that obidoxime adsorbs to HSA nanoparticles forming a monolayer. A maximum drug loading of 93.5 microg obidoxime/mg of nanoparticles at pH 8.3 was calculated. At higher concentrations the particle diameter increased significantly with obidoxime concentration leading to instable particle systems. The in vitro release of obidoxime from HSA nanoparticles showed a rapid release of the drug from the nanoparticles within 3 h.
