Pharmacokinetics of Novel Dopamine Transporter Inhibitor CE-123 and Modafinil with a Focus on Central Nervous System Distribution.

S-CE-123, a novel dopamine transporter inhibitor, has emerged as a potential candidate for cognitive enhancement. The objective of this study was to compare the tissue distribution profiles, with a specific focus on central nervous system distribution and metabolism, of S-CE-123 and R-modafinil. To address this objective, a precise liquid chromatography-high resolution mass spectrometry method was developed and partially validated. Neuropharmacokinetic parameters were assessed using the Combinatory Mapping Approach. Our findings reveal distinct differences between the two compounds. Notably, S-CE-123 demonstrates a significantly superior extent of transport across the blood-brain barrier (BBB), with an unbound brain-to-plasma concentration ratio (Kp,uu,brain) of 0.5, compared to R-modafinil's Kp,uu,brain of 0.1. A similar pattern was observed for the transport across the blood-spinal cord barrier. Concerning the drug transport across cellular membranes, we observed that S-CE-123 primarily localizes in the brain interstitial space, whereas R-modafinil distributes more evenly across both sides of the plasma membrane of the brain's parenchymal cells (Kp,uu,cell). Furthermore, our study highlights the substantial differences in hepatic metabolic stability, with S-CE-123 having a 9.3-fold faster metabolism compared to R-modafinil. In summary, the combination of improved BBB transport and higher affinity of S-CE-123 to dopamine transporters in comparison to R-modafinil makes S-CE-123 a promising candidate for further testing for the treatment of cognitive decline.

Quantification of atropine sulphate monohydrate and obidoxime dichloride in two-chamber autoinjectors for accessing uniformity of dosage.

In the treatment of organophosphate poisoning atropine sulphate monohydrate (AT) and obidoxime dichloride (OB) play a vital role. Currently, the Austrian Armed Forces use the DOUBLEPEN OA two-chamber autoinjector (ChemProtect) to administer these two drugs. The autoinjector is a part of military standard equipment as a "Basic CBRN-First Aid Kit" and contains OB and AT with a declared concentration of 220 mg/2 ml and 2 mg/2 ml, respectively. Especially in the two-chamber autoinjectors, it is highly possible that not all the content of the antidote solution is administered when the autoinjector is triggered. The purpose of the study was to analyze one hundred DOUBLEPEN OA autoinjectors from two different production batches (1707068 and 1707067) for volume loss, drug content and uniformity of dosage unit. Uniformity of dosage units, assessed by the content uniformity method (Chapter 2.9.40 of the European Pharmacopeia), requires the calculation of an acceptable value to quantify the uniformity of the drug product. An acceptance value for the first 10 dosage units of 15.0% or below is considered acceptable. The loss of volume was calculated by determining the density and mass of the solution after triggering the autoinjector. A quantitative high-performance liquid chromatography method has been developed and in-house validated for the determination of the content of two drugs. According to International Council for Harmonisation guidelines, the analytical method was proven to be accurate and repeatable. The obtained results show that the average loss of volume after injection was 5%, and the average content of OB and AT for batch 1707068, was 216.5 and 1.9 mg, while for batch 1707067 it was 224.2 and 2.0 mg, respectively. Although the loss of volume and content were observed, the calculated acceptance value for both production batches met the requirements of uniformity of dosage unit by the European Pharmacopeia.