Electroporation-delivered transdermal neostigmine in rats: equivalent action to intravenous administration

[Investigations into the distribution of neohistamine methylsulfate in the organism of the warm blooded animals following its intragastric administration]

The objective - of the present study was to elucidate the specific features of the distribution of neohistamine methylsulfate (proserin) in the organism of the omnivorous warm blooded animals following its intragastric administration. The analytical methods included TLC, HPLC, and UV-spectrophotometry. Neohistamine methylsulfate was administered intrgastrically to the male Wistar rats at a dose equivalent to the triple LD₅₀ dose. The substance of interest was extracted by acetone from the biological matrices of the dead animals and purified by sequential treatment with the relevant solvents and chromatography in a thin layer of the reverse-phase sorbent (C₁₄-C₁₅ bonded phase model) with the elution in the buffer solution (pH 1.98) - acetone (8:2) system. The compound of interest was identified based on the Rf values (obtained by TLC), retention time (in HPLC), and the spectral characteristics. The quantitative determination of the analyte in the biomatrices was performed with the use of UV spectrophotometry. The analytical methods were validated based on the criteria for linearity, selectivity, correctness, and precision as well as detection threshold and results of quantitation. The largest amount of the study compound were determined in the heart (365.2±33.94 mcg/g), spleen (288.6±24.97 mcg/g), kidney (127.6±9.33 mcg/g), and the gastric walls (124.6±12.17 mcg/g) of the experimental animals.

Reevaluation and update on efficacy and safety of neostigmine for reversal of neuromuscular blockade

Postoperative residual neuromuscular block is a serious threat which endangers the patient safety. Neostigmine has been the most commonly used anticholinesterase for the pharmacological reversal of neuromuscular blockade. Although newer agents have been introduced recently, neostigmine has some irreplaceable advantages, including broad-spectrum reversal of all nondepolarizing neuromuscular blocking drugs, low cost, and availability of more related data for clinical practice to refer to. Neostigmine is also noticed to have some drawbacks, such as the inability to reverse profound and deep blockade, potential induction of muscle weakness, cardiovascular adverse effects, and so on. Data on the usage of neostigmine in the geriatric and the pediatric population are still insufficient. Some discrepancies are observed in the results from previous studies which need further investigation. However, recent studies offer some renewed information. Regarding both efficacy and safety, the key for successful reversal of neuromuscular blockade is to use neostigmine “appropriately,” optimizing the dosage and timing of administration under close monitoring.

Controlled release of optimized electroporation enhances the transdermal efficiency of sinomenine hydrochloride for treating arthritis in vitro and in clinic

Sinomenine hydrochloride (SH) is an ideal drug for the treatment of rheumatoid arthritis and osteoarthritis. However, high plasma concentration of systemically administered SH can release histamine, which can cause rash and gastrointestinal side effects. Topical delivery can increase SH concentration in the synovial fluid without high plasma level, thus minimizing systemic side effects. However, passive diffusion of SH was found to be inefficient because of the presence of the stratum corneum layer. Therefore, an effective method is required to compensate for the low efficiency of SH passive diffusion. In this study, transdermal experiments in vitro and clinical tests were utilized to explore the optimized parameters for electroporation of topical delivery for SH. Fluorescence experiment and hematoxylin and eosin staining analysis were performed to reveal the mechanism by which electroporation promoted permeation. In vitro, optimized electroporation parameters were 3 KHz, exponential waveform, and intensity 10. Using these parameters, transdermal permeation of SH was increased by 1.9–10.1 fold in mice skin and by 1.6–47.1 fold in miniature pig skin compared with passive diffusion. After the electroporation stimulation, the intercellular intervals and epidermal cracks in the skin increased. In clinical tests, SH concentration in synovial fluid was 20.84 ng/mL after treatment with electroporation. Therefore, electroporation with optimized parameters could significantly enhance transdermal permeation of SH. The mechanism by which electroporation promoted permeation was that the electronic pulses made the skin structure looser. To summarize, electroporation may be an effective complementary method for transdermal permeation of SH. The controlled release of electroporation may be a promising clinical method for transdermal drug administration.