[Preparation of microemulsion gel loading enriched ingredients of Epimedii Folium and its pharmacodynamics evaluation]

On the basis of previous studies, this study prepared and evaluated microemulsion gel loading enriched ingredients of Epimedii Folium and investigated its protective effect against peripheral nervous system damage caused by chemotherapeutics. The preparation method and the type and dosage of the matrix were investigated from rheology, preparation difficulty, and drug loading. Then the optimal prescription was determined and the microemulsion gel loading enriched ingredients of Epimedii Folium was prepared. The in vitro release and transdermal behaviors of the gel were investigated in the Franz diffusion cell with epimedin A1,A,B,C, and icariin as evaluation indicators. The oxaliplatin-induced peripheral neuropathy(OIPN) model was established in Wistar rats. The protective effect of the microemulsion gel loading enriched ingredients of Epimedii Folium against peripheral nervous system damage caused by chemotherapeutics was evaluated by behavioral measurement after drug administration and histopathological examination of dorsal root ganglia and sciatic nerve. The preparation process of the microemulsion gel loading enriched ingredients of Epimedii Folium was stable, and the release of the five components was consistent with the Hixson-Crowell cube root law. Behavioral indicators intuitively showed that the drug could effectively relieve mechanical allodynia caused by oxaliplatin. The histopathological examination showed that the drug can improve neuron damage in the dorsal root ganglia, axon degeneration, and demyelination caused by oxaliplatin. Therefore, the preparation process of the microemulsion gel loading enriched ingredients of Epimedii Folium is feasible, which can achieve stable drug release. It has a certain therapeutic effect on chemotherapy-induced peripheral neuropathy(CIPN).

[Comparative study on in vivo and in vitro permeability of Huoxue Zhitong gel patch and microemulsion gel]

This study aims to establish a method for determination of paeonol(Pae), eugenol(Eug), and piperine(Pip) content in receptor liquid and research on the permeability and pharmacokinetics of Huoxue Zhitong gel patch and microemulsion gel. The Franz diffusion experiment was conducted to assess the percutaneous permeability, and the microdialysis method was employed to assess pharmacokinetics of Huoxue Zhitong gel patch and microemulsion gel. The content of Pae, Eug, and Pip in receptor liquid in vitro and in vivo was determined by HPLC and UPLC-MS. The Q_n and J_(ss) of Pae, Eug, and Pip in the gel patch were significantly higher than those in the microemulsion gel, indicating that the drug release was faster in the gel patch. The C_(max), AUC_(0-760), and MRT of Pae, Eug, and Pip in the gel patch were higher than those in the microemulsion gel, indicating that the gel patch can promote the penetration and prolong the skin residence of the drug. The results of this study provide reference for improving the dosage form of Huoxue Zhitong patch.

[Preparation of compound liquorice microemulsion gel and its pharmacodynamics evaluation]

Based on the previous study of compound liquorice microemulsion, this paper aims to prepare the compound liquorice microemulsion gel and investigate its pharmacodynamics of chronic eczema. The type, dosage and adding method of gel matrix, and formula dosage of humectant were optimized by single factor method to obtain the formula and preparation technique of the gel. With glycyrrhizic acid, glycyrrhetin and oxymatrine used as evaluation indexes, the Franz diffusion cell method was adopted to monitor the in vitro release profile of the gel. Eczema model of delayed-type hypersensitivity in mice was chosen to detect the ear swelling rate, degree of inflammatory cell infiltration of ear pieces, and pathological changes of ear pieces, so as to investigate the therapeutic effect of the microemulsion gel. The preparation process of the compound liquorice microemulsion gel was stable. The release of glycyrrhizin and oxymatrine was most consistent with the Hixcon-Crowell kinetic model, while the release of glycyrrhizic acid was most consistent with the Ritger-Peppas kinetic model. The pharmacodynamics studies proved that compound liquorice microemulsion gel could significantly reduce the ear swelling rate in mice, with good anti-inflammatory effect as well as the ability to resist the pathological changes of chronic eczema and inhibit the infiltration of dermal inflammatory cells. Therefore, the preparation process of compound liquorice microemulsion gel is feasible, with stable drug release and a significant therapeutic effect on chronic eczema.

Development of galangal essential oil-based microemulsion gel for transdermal delivery of flurbiprofen: simultaneous permeability evaluation of flurbiprofen and 1,8-cineole

Flurbiprofen (FP) is one of the most potent nonsteroidal anti-inflammatory drugs with very low bioavailability of approximately 12% following transdermal administration, compared to that after oral administration. This study aimed to deliver FP as a microemulsion (ME) gel by transdermal administration. Galangal essential oil (GEO) was extracted from Rhizoma Alpiniae Officinarum and identified by GC-MS. The most abundant constituent was determined to be 1,8-cineole (52.06%). Compared to azone, GEO was proved to exert significantly higher (p < .01) penetration enhancement effect and significantly (p < .001) lower skin cell toxicity. The formulation (FP-GEO-ME gel) was prepared using GEO as an oil phase and a penetration enhancer. Compared to that of FP solution, the enhancement ratio (ER) of FP-GEO-ME gel was 4.06. In addition, more than 25% 1,8-cineole permeated through the rat skin. In vivo pharmacokinetic studies revealed that the AUC_0-t of FP after transdermal administration of FP-GEO-ME gel was higher by approximately 4.56-fold than that of marketed FP cataplasms. The relative bioavailability of FP and 1,8-cineole after transdermal administration compared to oral administration of FP-GEO-ME were determined to be 96.58% and 85.49%, respectively. FP-GEO-ME gel significantly inhibited carrageenan-induced hind-paw edema and decreased PGE2 levels in rat serum. GEO-ME gel also exhibited significant anti-inflammatory effects at 2 h after the therapy (p < .05). The synergistic effects of FP and GEO were expected for the application of FP-GEO-ME gel. In conclusion, GEO-ME gel may be a promising formulation for transdermal administration of anti-inflammatory hydrophobic drugs, such as FP.

[Effect and mechanism of essential oil from Zanthoxylum bungeanum in microemulsion gel preparation on percutaneous delivery of complex components]

This study aimed to investigate the transdermal enhancing effect of essential oil from Zanthoxylum bungeanum(Z. bungeanum oil) in microemulsion gel(ZO-ME-gel) on permeation of different components,and reveal the transdermal enhancing mechanism of ZO-ME-gel. A series of components with different log P values were selected as model drugs and encapsulated in ZO-ME-gel to simplify and characterize the complex components of traditional Chinese medicine. The transdermal behavior of the model drugs was further examined using the improved Franz diffusion cell method. Then attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR),differential scanning calorimetry(DSC) studies and hematoxylin-eosin(HE) staining were used to investigate the effects of Z. bungeanum oil and ZO-ME-gel on keratin,intercellular lipids and microstructure of the stratum corneum(SC). The results showed that Z. bungeanum oil and ZO-ME-gel had a good transdermal enhancing effect on both hydrophilic and lipophilic drugs,and the best effect was achieved when log P value was-0. 5. The transdermal enhancing mechanism of Z. bungeanum oil and ZO-ME-gel was related to affecting the order of the SC lipids,changing lipid fluidity and protein conformation,and disrupting the integrity of the SC structure. 5% Z. bungeanum oil had greater transdermal enhancing effect and destruction of SC structure than ZO-ME-gel. These results suggested that Z. bungeanum oil loaded in microemulsion gel still had a good transdermal enhancing effect although the effect was not as great as Z. bungeanum oil itself,in addition,ZO-ME-gel was less irritating to the skin and safer to use,which had a guiding role in the development and clinical application of Z. bungeanum oil-containing traditional Chinese medicine topical preparations.

Design and Development of Repaglinide Microemulsion Gel for Transdermal Delivery

Microemulsion formulation of repaglinide, a BCS class II hypoglycemic agent with limited oral bioavailability, was developed considering its solubility in various oils, surfactants, and cosurfactants. The pseudo-ternary phase diagrams for microemulsion regions were constructed by water titration method at K _m 1:1 and characterized for optical birefringence, percentage transmittance, pH, refractive index, globule size, zeta potential, viscosity, drug content, and thermodynamic stability. To enhance the drug permeation and residence time, the optimized microemulsions having mean globule size of 36.15 ± 9.89 nm was gelled with xanthan gum. The developed microemulsion-based gel was characterized for globule size, zeta potential, pH, and drug content. All evaluation parameters upon gelling were found to be satisfactory. Ex vivo permeability study across rat skin demonstrated higher steady-state flux (P < 0.05) for microemulsion of repaglinide in comparison to the repaglinide microemulsion gel. At the end of 24 h, the cumulative drug permeation from microemulsion and microemulsion gel was found to be 229.19 ± 24.34 and 180.84 ± 17.40 μg/cm², respectively. The microemulsion formulation showed 12.30-fold increase in flux as compared to drug suspension with highest enhancement ratio (E _r ) of 12.36. Whereas microemulsion gel exhibited 10.97-fold increase in flux (with highest E _r , 11.78) as compared to repaglinide (RPG) suspension. In vivo efficacy study was performed in normal Sprague-Dawley rats by using oral glucose tolerance test. Results of RPG transdermal microemulsion gel demonstrated remarkable advantage over orally administered RPG by reducing the glucose level in controlled manner. Hence, it could be a new, alternative dosage form for effective therapy of type 2 diabetes mellitus.

PREPARATION AND PROPERTIES OF COMPOUND ARNEBIAE RADIX MICROEMULSION GEL

Background:

Compound Arnebiae radix oil has been clinically applied to treat burns and scalds for a long time. However, it is unstable and inconvenient to use. The aim of this study was to prepare a compound Arnebiae radix microemulsion gel for transdermal delivery system and evaluate its characteristics.

Materials and Methods:

Based on the solubility of Shikonin, the active component of Arnebiae radix and the results of phase studies, adequate ratio of each component in microemulsion was determined. The optimized microemulsion gel was prepared using Carbomer 940. The gels were characterized in terms of appearance, preliminary stability test and the content of Shikonin in the compound Arnebiae radix microemulsion gel with HPLC analysis.

Results:

The optimized conditions for preparing microemulsion were Tween-80, glycerin, isopropyl myristate (IPM) with the ratio of 6:3:2. The optimal microemulsion gel was obtained with Carbomer 940 (1.0%).

Conclusion:

The prepared compound Arnebiae radix microemulsion gel showed good stability over time. It is more convenience in application than the previous used formulations.