[Determination of main flavone glycosides in Flos Chrysanthemi and observation of factors influenced contents].

OBJECTIVE: To determine and compare the content of luteolin-7-O-beta-D-glucoside and apigenin-7-O-beta-D-glucoside in Flos Chrysanthemi from different collection time, sources, grades and processes. METHOD: The contents were determined by RP-HPLC. Zorbax SB C18 column (4.6 mm x 250 mm, 5 microm) was used as analysis column, the mobile phase was acetonitrile-pH 2.0 phosphate buffer solution with gradient elution, the detector was set at 338 nm. RESULT: The contents of two components changed at some degree in Flos Chrysanthemi from different collection time, different plant sites or with different grades, while the contents varied obviously among Flos Chrysanthemi from different source and different sorts. No obvious difference was found in Flos Chrysanthemi from different year. CONCLUSION: The contents of two components were influenced by process, plane site, source and sorts, especially by source and sorts.

Hyaluronic acid-coated niosomes facilitate tacrolimus ocular delivery: Mucoadhesion, precorneal retention, aqueous humor pharmacokinetics, and transcorneal permeability.

Tacrolimus (FK506) was used to prevent corneal allograft rejection in patients who were resistant to steroids and cyclosporine. However, the formulation for FK506 ocular delivery remained a challenge due to the drug's high hydrophobicity, high molecular weight, and eye's physiological and anatomical constraints. The aim of this project is to develop an ocular delivery system for FK506 based on a combined strategy of niosomes and mucoadhesive hyaluronic acid (HA), i.e., FK506HA-coated niosomes, which exploits virtues of both niosomes and HA to synergistically improve ophthalmic bioavailability. The FK506HA-coated niosomes were characterized with particle size, zeta potential, and rheology behavior. Mucoadhesion of FK506HA-coated niosomes to mucin was investigated through surface plasmon resonance in comparison with non-coated niosomes and HA solution. The results showed that niosomes possessed adhesion to mucin, and HA coating enhanced the adhesion. The in vivo precorneal retention was evaluated in rabbit, and the results showed that HA-coated niosomes prolonged the residence of FK506 significantly in comparison with non-coated niosomes or suspension. Aqueous humor pharmacokinetics test showed that area under curve of HA-coated niosomes was 2.3-fold and 1.2-fold as that of suspension and non-coated niosomes, respectively. Moreover, the synergetic corneal permeability enhancement of the hybrid delivery system on FK506 was visualized and confirmed by confocal laser scanning microscope. Overall, the results indicated that the hybrid system facilitated FK506 ocular delivery on mucoadhesion, precorneal retention, aqueous humor pharmacokinetics and transcorneal permeability. Therefore, HA-coated niosomes may be a promising approach for ocular targeting delivery of FK506.

Combination of hydrotropic nicotinamide with nanoparticles for enhancing tacrolimus percutaneous delivery.

Tacrolimus (FK506), an effective immunosuppressant for treating inflammatory skin diseases, hardly penetrates into and through the skin owing to its high hydrophobicity and molecular weight. The aim of this study was to develop a hybrid system based on nicotinamide (NIC) and nanoparticles (NPs) encapsulating FK506, such as FK506-NPs-NIC, for facilitating percutaneous delivery, which exploited virtues of both NIC and NPs to obtain the synergetic effect. Solubility and percutaneous permeation studies were carried out. The results showed that NIC could increase the solubility and permeability of FK506 and that 20% (w/v) NIC presented higher FK506 permeability and was thus chosen as the hydrotropic solution to solubilize FK506 and prepare FK506-NPs-NIC. Hyaluronic acid (HA) was chemically conjugated with cholesterol (Chol) to obtain amphiphilic conjugate of HA-Chol, which self-assembled NPs in 20% NIC solution containing FK506. The particle size, zeta potential, and morphology of NPs were characterized. The encapsulation efficiency and in vitro percutaneous permeation of NPs were evaluated in the presence and absence of NIC. The results demonstrated that hydrotropic solubilizing FK506 was readily encapsulated into NPs with a higher encapsulation efficiency of 79.2%±4.2%, and the combination of NPs with NIC exhibited a significantly synergistic effect on FK506 deposition within the skin (2.39±0.53 µg/cm(2)) and penetration through the skin (13.38±2.26 µg/cm(2)). The effect of the combination of NPs with NIC on drug permeation was further visualized by confocal laser scanning microscope through in vivo permeation studies, and the results confirmed that NPs-NIC synergistically enhanced the permeation of the drug into the skin. The cellular uptake performed in HaCaT cells presented a promoting effect of NPs on cellular uptake. These overall results demonstrated that HA-Chol-NPs-NIC can synergistically improve the percutaneous delivery of FK506, and it is a novel potential strategy based on a nano-sized carrier for FK506 to treat skin diseases.

Microemulsion based gel for topical dermal delivery of pseudolaric acid B: In vitro and in vivo evaluation.

Pseudolaric acid B (PAB) possesses comparable fungicidal activity against Candida albicans to amphotericin B and antifungal activity against azole-resistant Candida species. However, its poor water solubility makes the formulation a considerable challenge for dermal permeation of PAB. The aim of this project was to improve the solubility and eventually the dermal permeability and bioavailability by developing a microemulsion based gel for PAB (PAB ME-gel). PAB ME-gel was formulated using isopropyl myristate as oil phase, cremphor EL as surfactant, transcutol P as cosurfactant, and carbopol as gel matrix, and characterized by droplet size, morphology, pH, and rheology. The 3 month storage test showed that PAB ME-gel possessed good physicochemical stability. In vitro permeation of PAB through rat skin from ME-gel was investigated in comparison with PAB microemulsion (PAB ME) and PAB hydrogel (PAB gel), and results showed that ME significantly enhanced PAB retention in the skin and permeation through the skin whether it was incorporated into the gel or not. In vivo dermatopharmacokinetics study using microdialysis further confirmed that ME-gel significantly increased PAB dermal bioavailability compared with the gel (41.95 ± 8.89 µg/ml vs. 13.90 ± 2.22 µg/ml). In vitro sensitivity against C. albicans test indicated that the antifungal activity of PAB ME-gel increased with the increase of PAB loading, and 8 mg/g of PAB ME-gel exhibited a higher antifungal activity than that of 20mg/g miconazole nitrate cream. In vivo antifungal activity evaluation in C. albicans infected guinea pigs showed that 8 mg/g of PAB ME-gel exhibited a higher efficacy than that of 20mg/g miconazole nitrate cream after 7 day treatment. Overall, the results indicated that the ME enhanced in vitro permeability, in vivo dermal bioavailability, and antifungal activity of PAB. Therefore, ME-gel may be a promising approach for topical dermal delivery of PAB to treat skin fungal infection.

Synergetic skin targeting effect of hydroxypropyl-ß-cyclodextrin combined with microemulsion for ketoconazole.

The objective was to develop a ternary skin targeting system for ketoconazole (KET) using a combined strategy of microemulsion (ME) and cyclodextrin (HP-ß-CD), i.e., KET-CD-ME, which exploits both virtues of cyclodextrin complex and ME to obtain the synergetic effect. KET-CD-ME was formulated using Labrafil M 1944 CS as oil phase, Solutol HS 15 as surfactant, Transcutol P as cosurfactant, and HP-ß-CD solution as aqueous phase. The formulation of KET-CD-ME was optimized and the optimal formulation was characterized in terms of particle size, size distribution, pH value, and viscosity. Long term stability experiment showed that HP-ß-CD could increase the physical stability of ternary system and KET chemical stability. Percutaneous permeation of KET from KET-CD-ME in vitro through rat skin was investigated in comparison with KET microemulsion (KET-ME), KET HP-ß-CD inclusion solution (KET-CD), KET aqueous suspension, and commercial KET cream; the results showed that the combination of ME with HP-ß-CD exhibited significantly synergistic effect on KET deposition within the skin (29.38 ± 1.79 µg/cm(2)) and a slightly synergistic effect on KET penetration through the skin (11.3 µg/cm(2)/h). The enhancement of the combination on skin deposition was further visualized by confocal laser scanning microscope (CLSM). In vitro sensitivity against Candida parapsilosis test indicated that KET-CD-ME enhanced KET antifungal activity mainly owing to the solubilization of HP-ß-CD on KET in the ternary system. Moreover, the interactions between HP-ß-CD and KET in the ternary system were elucidated through microScale thermophoresis (MST) and 2D (1)H NMR spectroscopy. The profiles from MST confirmed the host-guest interactions of HP-ß-CD with KET in the ternary system and a deep insight into the interactions between KET and HP-ß-CD were obtained by means of 2D (1)H NMR spectroscopy. The results indicate that the ternary system of ME combination with HP-ß-CD may be a promising approach for skin targeting delivery of KET.