Preparation and physicochemical characterization of rotigotine drug-in-adhesive patch containing crystal growth inhibitor

Translation from Preclinical Research to Clinical Trials: Transdermal Drug Delivery for Neurodegenerative and Mental Disorders

Neurodegenerative diseases (NDs), particularly dementia, provide significant problems to worldwide healthcare systems. The development of therapeutic materials for various diseases has a severe challenge in the form of the blood-brain barrier (BBB). Transdermal treatment has recently garnered widespread favor as an alternative method of delivering active chemicals to the brain. This approach has several advantages, including low invasiveness, self-administration, avoidance of first-pass metabolism, preservation of steady plasma concentrations, regulated release, safety, efficacy, and better patient compliance. Topics include the transdermal method for therapeutic NDs, their classification, and the mechanisms that allow the medicine to enter the bloodstream through the skin. The paper also discusses the obstacles and potential outcomes of transdermal therapy, emphasizing the benefits and drawbacks of different approaches.

Using Polymers as Crystal Inhibitors to Prevent the Crystallization of the Rotigotine Patch

This study aimed to enhance the stability of the Rotigotine (ROT) patch using polymers as crystal inhibitors. Three polymers (Poloxamer 188, Soluplus, TPGS) were selected as crystal inhibitors to formulate ROT patches with varying drug loadings (20%, 40%, 60%, and 80%, w/w). SEM and XRD analysis revealed that the Soluplus and Soluplus-TPGS groups with a high concentration (80%, w/w) of ROT could be stored at room temperature for at least 90 days without crystallization. Moreover, the crystallization nucleation time and growth rate were utilized to assess the ability of Poloxamer 188, Soluplus, and TPGS to hinder the formation of ROT crystals and slow down its crystallization rate. Molecular docking results elucidated the intermolecular forces between ROT and different polymers, revealing their mechanisms for crystal inhibition. The ROT-Soluplus-TPGS combination exhibited the lowest binding free energy (-5.3 kcal/mol), indicating the highest binding stability, thereby effectively reducing crystal precipitation. In vitro skin permeation studies demonstrated that ROT patches containing crystal inhibitors exhibited promising transdermal effects. With increasing ROT concentration, the cumulative drug permeation substantially increased, while the lag time was notably reduced. This study offers novel insights for the development of ROT patches.

Formulation of intranasal surface engineered nanostructured lipid carriers of rotigotine: Full factorial design optimization, in vitro characterization, and pharmacokinetic evaluation

The objective of the present research was to develop, optimize, and evaluate rotigotine (RT)-loaded chitosan (CH) coated nanostructured lipid carriers (RT-CH-NLCs) for nose-to-brain delivery. The NLCs were prepared by homogenization and sonication technique as well as optimized by using three factors at three-level Box-Behnken design. The prepared NLCs were evaluated for particle size, zeta potential, entrapment efficiency, drug release, and ex vivo permeation. The pharmacokinetic study was conducted on albino Wistar rats to evaluate the bioavailability and neuropharmacokinetic parameters after intranasal administration of the optimized formulation (RT-CH-NLCs-OPT). The optimized formulation showed the particle size (170.48 ± 8.37 nm), PDI (0.19 ± 0.03), zeta potential (+ 26.73 mV), and entrapment efficiency (82.37 ± 2.48 %). In vitro drug release study displayed a sustained drug release pattern from RT-CH-NLCs-OPT (86.73±8.58 % in 24 h) in comparison to RT-Dis (98.61±7.24 % in 16 h). The permeability coefficient (PC) was found to be 11.39 ± 1.08×10^-4 cm.h^-1 and 2.34 folds higher than RT-Dis (4.85±1.53×10^-4 cm.h^-1). The relative bioavailability of RT from RT-CH-NLCs-OPT was 3.2-fold greater as compared to RT-Dis. The absolute bioavailability of RT after intranasal administration of RT-CH-NLCs-OPT was 2.1-fold higher than RT-CH-NLCs-OPT administered intravenously. The brain targeting and targeting potential was displayed by DTE (422.03 %) and DTP (76.03 %) after intranasal administration of RT-CH-NLCs-OPT as compared to RT-Dis (DTE 173.91 % and DTP 59.97 %). Furthermore, confocal laser scanning microscopy results confirmed better brain targeting for RT-CH-NLCs-OPT as compared to RT-Dis. From these findings, it could be concluded that RT-CH-NLCs could serve as a promising strategy for targeting RT through the intranasal route.

Co-Spray Dried Nafamostat Mesylate with Lecithin and Mannitol as Respirable Microparticles for Targeted Pulmonary Delivery: Pharmacokinetics and Lung Distribution in Rats

Coronavirus disease 2019 (COVID-19), caused by a new strain of coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly worldwide. Nafamostat mesylate (NFM) suppresses transmembrane serine protease 2 and SARS-CoV-2 S protein-mediated fusion. In this study, pharmacokinetics and lung distribution of NFM, administered via intravenous and intratracheal routes, were determined using high performance liquid chromatography analysis of blood plasma, lung lumen using bronchoalveolar lavage fluid, and lung tissue. Intratracheal administration had higher drug delivery and longer residual time in the lung lumen and tissue, which are the main sites of action, than intravenous administration. We confirmed the effect of lecithin as a stabilizer through an ex vivo stability test. Lecithin acts as an inhibitor of carboxylesterase and delays NFM decomposition. We prepared inhalable microparticles with NFM, lecithin, and mannitol via the co-spray method. The formulation prepared using an NFM:lecithin:mannitol ratio of 1:1:100 had a small particle size and excellent aerodynamic performance. Spray dried microparticles containing NFM, lecithin, and mannitol (1:1:100) had the longest residual time in the lung tissue. In conclusion, NFM-inhalable microparticles were prepared and confirmed to be delivered into the respiratory tract, such as lung lumen and lung tissue, through in vitro and in vivo evaluations.