[Molding matrix formulation of hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine preparations].

This study aims to optimize the matrix formulation for the hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine(TCM) preparations and verify the applicability of the formulation. The central composite design in JMP Pro 16.1.0 was employed to optimize the dosages of styrene-isoprene-styrene triblock copolymer(SIS), hydrogenated petroleum resin, and lightweight liquid paraffin, with the fine powder of Yipifang as the model drug(drug loading of 10%) and the sensory score and objective evaluation as the comprehensive evaluation indicators. The quality evaluation system of hot-melt pressure-sensitive adhesive plaster of personalized TCM preparations was established. The applicability of the optimized matrix formulation of hot-melt pressure-sensitive adhesive plaster was verified with 16 TCM preparations for external application. Furthermore, the applicability of the matrix formulation was investigated with different drug loadings. The general molding matrix formulation was SIS∶hydrogenated petroleum resin∶lightweight liquid paraffin 3∶3∶5. The optimized matrix formulation showed good molding properties and high quality scores for 16 TCM preparations and were suitable for the plastering of finely powdered decoction pieces with a loading capacity of 10% to 30%. The results suggest that the optimized matrix formulation has good applicability and is suitable for TCM preparations. The findings lay a foundation for the application and promotion of the hot-melt pressure-sensitive adhesive plasters of personalized TCM preparations.

Effect of modified bamboo lignin replacing part of C5 petroleum resin on properties of polyurethane/polysiloxane pressure-sensitive adhesive and its application on the wood substrate.

This paper reports a fresh and robust strategy to develop polyurethane/polysiloxane pressure-sensitive adhesives (PSAs) with excellent properties by replacing part of C5 petroleum resin with modified lignin. A unique aspect of this work is the use of renewable lignin to obtain modified monomers. The phenolic hydroxyl group of lignin is increased by 21.4% after demethylation, which will help to introduce 6-bromo-1-hexene into the lignin structure through Williamson method. The L3 lignin and C5 petroleum resin are mixed with polyurethane/polysiloxane prepolymer, and furthermore a series of PSAs are obtained under ultraviolet light. It turns out that L3 lignin can not only replace part of C5 petroleum resin, but also obtain attractive and controllable features. Especially when the mass ratio of C5 petroleum resin to L3 lignin is 6:4, compared with pure C5 petroleum resin, the 180° peel strength and the shear strength of PU46 are increased by 24.1% and 91.5% respectively. Additionally, the shear strength on the wood substrate is increased by 320.6%. This study provides an effective method for the preparation of high value-added lignin PSA, and expands the application fields of PSA.

Development of transdermal therapeutic formulation of CNS5161, a novel NMDA receptor antagonist, by utilizing pressure-sensitive adhesives II: improved transdermal absorption and evaluation of efficacy and safety.

The aim of this study was to prepare a transdermal therapeutic formulation of CNS5161, an NMDA receptor antagonist developed as a drug for neuropathic pain. Since a silicone pressure-sensitive adhesive (PSA) was found to be the best PSA for CNS5161 among six different PSAs examined in our previous study, the effects of the loading concentration of CNS5161 on release and rat skin permeability were investigated using silicone PSAs. The release of CNS5161 was elevated with an increase in the drug concentration from 1% to 14%. The transdermal flux at the steady state reached a plateau at 8% and over, while crystallization of CNS5161 was not observed for any formulation even at high drug concentrations. The drug concentration in rat skin at the steady state was also saturated at 8% and over, which correlated well with the transdermal flux at the steady state. Therefore, skin permeation clearance defined to the skin concentration at the steady state was almost constant at 0.21/h from 2% to 14% of CNS5161, which suggests that drug concentrations in the skin would be a driving force for transport of the drug to the receptor side. Since increasing the concentration of CNS5161 in the PSA patch was not able to elevate the transdermal flux, 12 formulations containing several permeation enhancers were examined to improve the transdermal transport of CNS5161. Among them, the formulation containing propylene glycol, diisopropyl adipate, and polyvinylpyrrolidone significantly increased the transdermal flux by approximately 1.8-fold by improving the diffusivity of CNS5161 in the skin, and also significantly enhanced the analgesic effect of CNS5161. This formulation caused only slight skin irritation, which indicated that it would be a promising transdermal therapeutic system for CNS5161.

Formulation and in vitro/in vivo evaluation of levodopa transdermal delivery systems.

This study aims to investigate the feasibility of Levodopa transdermal delivery systems (TDSs). Levodopa TDSs were formulated using various vehicles and permeation enhancers, and in vitro permeation and in vivo pharmacokinetic studies were carried out. In the in vitro study, ester-type vehicles showed relatively high enhancing effects; propylene glycol monocaprylate and propylene glycol monolaurate showed the highest permeation fluxes from both solution and pressure sensitive adhesive (PSA) TDS formulations. Lag time was dramatically shortened with PSA TDS formulations as compared with solution formulations. In the in vivo study, the addition of fatty acids increased blood drug concentrations regardless of the kind or concentration of fatty acid; the AUCinf increased up to 8.7 times as compared with propylene glycol (PG) alone. PSA TDS containing 10% linoleic acid exhibited prolonged Tmax as compared with oral form. Total clearance of L-dopa from PSA TDSs was significantly lower than from oral form (up to 86.8 times). Especially, PSA TDS containing 10% linoleic acid (LOA) revealed 76.2 fold higher AUCinf than oral administration. Based on our results, the L-dopa PSA TDS containing PG with 10% LOA could be used as a good adjuvant therapy for Parkinson's disease patients who experience symptom fluctuation by L-dopa oral administration.

Comparison on in vitro transdermal permeability, pharmacodynamics, and skin irritation of Guanjie Zhitong Patches based on two different matrixes / 中草药

Objective: To compare the differences in transdermal permeability, pharmacodynamics, and skin irritation of Guanjie Zhitong Patches based on two different formulations taking hot-melt pressure sensitive adhesive and rubber as matrixes. Methods: In vitro transdermal permeation was performed by means of Franz diffusion cells; The analgesic effect was evaluated by HAc-induced writhing response in mice and hot-plate test, while the anti-inflammatory action was assessed by xylem-induced ear edema in mice and albumin-induced paw edema in rats. The skin irritation of the two matrixes was investigated using guinea pig as model animal. Results: Patches based on hot-melt pressure sensitive adhesives showed better transdermal permeability, analgesic, and anti-inflammatory effects but less skin irritation than the rubber type patches. Conclusion: Hot-melt pressure sensitive adhesive is a kind of appropriate material to compose the patch matrix for Chinese herbal medicine, which has the good transdermal permeability and efficacy and less skin irritation.