Dermatopharmacokinetic and pharmacodynamic evaluation of a novel nanostructured formulation containing capsaicinoids for treating neuropathic pain

Ropivacaine microsphere-loaded electroconductive nerve dressings for long-acting analgesia and functional recovery following diabetic peripheral nerve injury

In recent years, electroconductive hydrogels (ECHs) have shown great potential in promoting nerve regeneration and motor function recovery following diabetic peripheral nerve injury (PNI), attributed to their similar electrical and mechanical characteristics to innate nervous tissue. It is well-established that PNI causes motor deficits and pain, especially in diabetics. Current evidence suggests that ropivacaine (ROP) encapsulated in poly lactic-co-glycolic acid (PLGA) microspheres (MSs) yield a sustained analgesic effect. In this study, an ECH electroconductive network loaded with MS/ROP (ECH-MS/ROP) was designed as a promising therapeutic approach for diabetic PNI to exert lasting analgesia and functional recovery. This dual delivery system allowed ROP's slow and sequential release, achieving sustained analgesia as demonstrated by our in vivo experiments. Meanwhile, this system was designed like a lamellar dressing, with desirable adhesive and self-curling properties, convenient for treating injured nerve tissues via automatically wrapping tube-like structures, facilitating the process of implantation. Our in vitro assays verified that ECH-MS/ROP was able to enhance the adhesion and motility of Schwann cells. Besides, both in vitro and in vivo studies substantiated that ECH-MS/ROP stimulated myelinated axon regeneration through the MEK/ERK signaling pathway, thereby improving muscular denervation atrophy and facilitating functional recovery. Therefore, this study suggests that the ECH-MS/ROP dressing provides a promising strategy for treating diabetic PNI to facilitate nerve regeneration, functional recovery and pain relief.

The Human Dermis as a Target of Nanoparticles for Treating Skin Conditions

Skin has a preventive role against any damage raised by harmful microorganisms and physical and chemical assaults from the external environment that could affect the body's internal organs. Dermis represents the main section of the skin, and its contribution to skin physiology is critical due to its diverse cellularity, vasculature, and release of molecular mediators involved in the extracellular matrix maintenance and modulation of the immune response. Skin structure and complexity limit the transport of substances, promoting the study of different types of nanoparticles that penetrate the skin layers under different mechanisms intended for skin illness treatments and dermo-cosmetic applications. In this work, we present a detailed morphological description of the dermis in terms of its structures and resident cells. Furthermore, we analyze the role of the dermis in regulating skin homeostasis and its alterations in pathophysiological conditions, highlighting its potential as a therapeutic target. Additionally, we describe the use of nanoparticles for skin illness treatments focused on dermis release and promote the use of metal-organic frameworks (MOFs) as an integrative strategy for skin treatments.

Co-Combination of Pregabalin and Withaniacoagulans-Extract-Loaded Topical Gel Alleviates Allodynia and Hyperalgesia in the Chronic Sciatic Nerve Constriction Injury for Neuropathic Pain in Animal Model

The current study reports the fabrication of co-combination gel using Pregabalin and Withania coagulans fruit extract to validate its effectiveness for neuropathic pain in chronic constriction injury (CCI) rat models. Three topical gels were prepared using Carbopol 934 through a pseudo-ternary phase diagram incorporating the Pregabalin (2.5%), Withania coagulans extract (2%), and co-combination of both Pregabalin (2.5%) and Withania coagulans extract (2%). Gels were characterized. FTIR showed a successful polymeric network of the gel without any interaction. The drug distribution at the molecular level was confirmed by XRD. The AFM images topographically indicated the rough surface of gels with a size range from 0.25 to 330 nm. DSC showed the disappearance of sharp peaks of the drug and extract, showing successful incorporation into the polymeric network of gels. The in vitro drug release of co-combination gel was 73% over 48 h. The mechanism of drug release by combination gel was Higuchi+ fickian with values of n (0.282) and R2 (0.947). An in vivo study for pain assessment via four methods: (i) heat hyperalgesia, (ii) cold allodynia, (iii) mechano-hyperalgesia, and (iv) dynamic mechano-allodynia, confirmed that topical treatment with co-combination gel reduced the pain significantly as indicated by the p value: R1 (p < 0.001), R2 (p < 0.001), R3 (p < 0.015), and R4 (p < 0.0344). The significance order was R2 (****) > R1 (***) > R3 (**) > R4 (*) > R5 (ns).

Multi-directionally evaluating the formation mechanism of 1,4-dihydropyridine drug nanosuspensions through experimental validation and computer-aided drug design

The poor aqueous solubility of 1,4-dihydropyridine drugs needs to be solved urgently to improve the bioavailability. Nanotechnology can improve drug solubility and dissolution by reducing particle size, but usually a specific polymer or surfactant is required for stabilization. In this study, Poloxamer-407(P-407) was screened as the optimal stabilize through energy simulation, molecular docking and particle size. morphological study, X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman, in vitro dissolution test and molecular simulation of interactions were utilized to explore the formation mechanisms of four 1,4-dihydropyridine drugs/P-407 nanosuspensions. The result shows that the optimized nanosuspensions had the particle size in the nano-size range and maintained the original crystal state. The in vitro dissolution rate of the nanosuspension was 3-4 times higher than the corresponding API and could reduce the restriction of drug dissolution in different pH environments. Raman spectroscopy, FTIR and molecular docking simulations provided strong supporting evidence for the formation mechanism of 1,4-dihydropyridine drugs/P-407 nanosuspensions at the molecular level, which confirmed that the stable intermolecular hydrogen bond adsorption and hydrophobic interaction were formed between the drug and P-407. This research will provide practical concepts and technologies, which are helpful to develop nanosuspensions for the same class of drugs.

Oral delivery of ambrisentan-loaded lipid-core nanocapsules as a novel approach for the treatment of pulmonary arterial hypertension

Ambrisentan (AMB) is an orphan drug approved for oral administration that has been developed for the treatment of pulmonary arterial hypertension (PAH), a chronic and progressive pathophysiological state that might result in death if left untreated. Lipid-core nanocapsules (LNCs) are versatile nanoformulations capable of loading lipophilic drugs for topical, vaginal, oral, intravenous, pulmonary, and nasal administration. Our hypothesis was to load AMB into these nanocapsules (LNC_amb) and test their effect on slowing or reducing the progression of monocrotaline-induced PAH in a rat model, upon oral administration. LNC_amb displayed a unimodal distribution of diameters (around 200 nm), negative zeta potential (-11.5 mV), high encapsulation efficiency (78%), spherical shape, and sustained drug release (50-60% in 24 h). The in vivo pharmacodynamic effect of the LNC_amb group was evaluated by observing the echocardiography, hemodynamic, morphometric, and histological data, which showed a significant decrease in PAH in this group, as compared to the control group (AMB_solution). LNC_amb showed the benefit of reversing systolic dysfunction and preventing vascular remodeling with greater efficacy than that observed in the control group. The originality and contribution of our work reveal the promising value of this nanoformulation as a novel therapeutic strategy for PAH treatment.

HPLC-MS/MS studies of brimonidine in rabbit aqueous humor by microdialysis

Aim: The pharmacokinetic study of the brimonidine tartrate in situ gel in the anterior chamber of the rabbit eye was studied by microdialysis technique, and samples were analyzed by HPLC-MS/MS. Materials & methods: It was monitored in ESI mode at transition 291.9→212.0 and 296.0→216.0 for brimonidine and internal standard, respectively. Acetonitrile and 0.1% aqueous formic acid (50:50, v/v) were used as the mobile phase at 0.4 ml/min. Results & conclusion: It showed a good linear correlation between 5 and 5000 ng/ml in microdialysis solution, and the inter- and intra-day precision (relative standard deviation) was less than 4.0%. The pharmacokinetic study showed that the AUC(0-t) of in situ gel was 3.5-times than that of eyedrops, which significantly improve the bioavailability of brimonidine.