Aihua Yu

Development and evaluation of penciclovir-loaded solid lipid nanoparticles for topical delivery.

The objective of this investigation was to develop solid lipid nanoparticles (SLNs) of penciclovir and evaluate the potential of SLNs as the carrier of penciclovir for topical delivery. Penciclovir-loaded SLNs were prepared by a double (W/O/W) emulsion technique. The SLNs presented spherical with the mean diameter of 254.9 nm. The entrapment efficiency, drug loading and zeta potential were 92.40%, 4.62% and -25.0 mV, respectively. DSC study showed that penciclovir encapsulated in SLNs was in the amorphous form. The cumulative amount of penciclovir penetrated through excised rat skin from SLNs was more than 2-fold that of the commercial cream as a control at 12h after administration. There was no significant difference of penciclovir content deposited in epidermis between the cream and SLNs administrated for 2, 6 and 12h, while SLNs increased the cumulative uptake of penciclovir in dermis significantly at the same intervals. Microscopic pictures showed that the interaction between SLNs and the skin surface changed the apparent morphology of stratum corneum and broke the close conjugation of corneocyte layers, which was the possible reason that SLNs increased the permeation of penciclovir into skin dermis. It can be concluded from our study that SLNs provide a good skin targeting effect and may be a promising carrier for topical delivery of penciclovir.

Formulation design of microemulsion for dermal delivery of penciclovir

The purpose of the present study was to evaluate the potential application of microemulsions as a dermal drug delivery loading penciclovir. The pseudo-ternary phase diagrams were developed for various microemulsion formulations composed of oleic acid (oil phase), Cremorphor EL (surfactant) and ethanol (cosurfactant). Composition of microemulsion systems was optimized using simplex lattice mixture design including the concentrations of surfactant, cosurfactant and water (independent variables) and the solubility and the cumulative amount of penciclovir permeated through excised mouse skins per unit area (response variables). The physicochemical properties of the optimized microemulsion and the permeating ability of penciclovir from microemulsions were also investigated. The results showed that the optimized microemusion formulation was composed of oleic acid (5%, w/w), Cremorphor EL (20%, w/w), ethanol (30%, w/w) and water (45%, w/w). The mean particle diameter was 36.5nm and solubility of penciclovir in the emulsion was 7.41 mg g(-1). The cumulative amount of penciclovir permeated through excised mouse skins from microemulsion was about 3.5 times that of the commercial cream. The conclusion was that the permeating ability of penciclovir was significantly increased from the microemulsion formulation compared with commercial cream.

Advances in nanotechnology-based delivery systems for curcumin.

Curcumin (CUR), a bioactive component of turmeric, which is a commonly used spice and nutritional supplement, is isolated from the rhizomes of Curcuma longa Linn. (Zingiberaceae). In recent years, the potential pharmacological actions of CUR in inflammatory disorders, cardiovascular disease, cancer, Alzheimers disease and neurological disorders have been shown. However, the clinical application of CUR is severely limited by its main drawbacks such as instability, low solubility, poor bioavailability and rapid metabolism. Multifarious nanotechnology-based delivery approaches have been used to enhance the oral bioavailability, biological activity or tissue-targeting ability of CUR. This article reviews potential novel drug delivery systems for CUR including liposomes, polymeric nanoparticles, solid lipid nanoparticles, micelles, nanogels, nanosuspensions, nanoemulsions, complexes and dendrimer/dimer, which provide promising results for CUR to improve its biological activities.

Microemulsion-based hydrogel formulation of penciclovir for topical delivery

The purpose of this study was to investigate microemulsion-based hydrogel (MBH) as a topical delivery system for penciclovir. Topical delivery of penciclovir in the forms of microemulsion, MBH and the commercial cream was evaluated in vitro and in vivo. The results of permeation test in vivo in mice showed that compared with the commercial cream, MBH and microemulsion could significantly increase the permeation of penciclovir into both epidermis and dermis. Stability test showed that MBH stored at 4 degrees C for 3 months had no significant change in physicochemical properties. Skin irritation test in rabbit demonstrated that single application or multiple applications of MBH did not cause any erythema or edema, slight skin irritation for microemulsion. Microstructure changes of skins after administration observed under light microscope and scanning electron microscope (SEM) might result from the interaction of the ingredients of microemulsion with skins, which was related with the permeation enhancement of penciclovir. It can be concluded that the MBH could be a promising vehicle for topical delivery of penciclovir.

A novel folate-modified self-microemulsifying drug delivery system of curcumin for colon targeting

Background The objective of this study was to prepare, characterize, and evaluate a folate-modified self-microemulsifying drug delivery system (FSMEDDS) with the aim to improve the solubility of curcumin and its delivery to the colon, facilitating endocytosis of FSMEDDS mediated by folate receptors on colon cancer cells. Methods Ternary phase diagrams were constructed in order to obtain the most efficient self-emulsification region, and the formulation of curcumin-loaded SMEDDS was optimized by a simplex lattice experiment design. Then, three lipophilic folate derivatives (folate-polyethylene glycol-distearoylphosphatidylethanolamine, folate-polyethylene glycol-cholesteryl hemisuccinate, and folate-polyethylene glycol-cholesterol) used as a surfactant were added to curcumin-loaded SMEDDS formulations. An in situ colon perfusion method in rats was used to optimize the formulation of FSMEDDS. Curcumin-loaded FSMEDDS was then filled into colon-targeted capsules and the in vitro release was investigated. Cytotoxicity studies and cellular uptake studies was used in this research. Results The optimal formulation of FSMEDDS obtained with the established in situ colon perfusion method in rats was comprised of 57.5% Cremophor® EL, 32.5% Transcutol® HP, 10% Capryol™ 90, and a small amount of folate-polyethylene glycol-cholesteryl hemisuccinate (the weight ratio of folate materials to Cremophor EL was 1:100). The in vitro release results indicated that the obtained formulation of curcumin could reach the colon efficiently and release the drug immediately. Cellular uptake studies analyzed with fluorescence microscopy and flow cytometry indicated that the FSMEDDS formulation could efficiently bind with the folate receptors on the surface of positive folate receptors cell lines. In addition, FSMEDDS showed greater cytotoxicity than SMEDDS in the above two cells. Conclusion FSMEDDS-filled colon-targeted capsules are a potential carrier for colon delivery of curcumin.

Preparation and characterization of intravenously injectable curcumin nanosuspension

The interest in nanosuspensions by the pharmaceutical industry is increasing given several nanosuspension products currently on the market for poorly soluble drugs. In this study, a novel dosage form for curcumin (CUR), CUR nanosuspension (CUR-NS), was successfully prepared by high pressure homogenization to improve CUR’s cytotoxicity, as well as improve its application via intravenous injection. Characterization of the CUR-NS was evaluated by morphology, size, zeta potential, solubility, dissolution rate, and crystal state of drug. The nanoparticles for CUR-NS presented a sphere-like shape under transmission electron microscopy with an average diameter of 250.6 nm and the zeta potential of CUR-NS was −27.92 mV. Solubility and dissolution rate of CUR in the form of CUR-NS were significantly increased due to the small particle size and the crystalline state of CUR was preserved to increase its stability against degradation. Superior cytotoxicity in Hela and MCF-7 cells was obtained for CUR-NS compared with CUR solution. The safety evaluation showed that, compared with the CUR solution, CUR-NS provided less local irritation and phlebitis risks, lower rate of erythrocyte hemolysis. These findings suggest that CUR-NS may represent a promising new drug formulation for intravenous administration in the treatment of certain cancers.

N-trimethyl chitosan chloride-coated liposomes for the oral delivery of curcumin

The aims of this study were to design the formulation of curcumin (CUR) liposomes coated with N-trimethyl chitosan chloride (TMC) and to evaluate in vitro release characteristics and in vivo pharmacokinetics and bioavailability of TMC-coated CUR liposomes in rats. The structure of synthesized TMC was examined by infrared spectroscopy, with the presence of trimethyl groups, and by proton nuclear magnetic resonance spectroscopy, indicating the high degree of substitution quaternization (65.6%). Liposomes, composed of soybean phosphotidylcholine, cholestrol, and D-α-tocopheryl polyethylene glycol 1000 succinate, were prepared by a thin-film dispersion method. Characteristics of the CUR liposomes, including entrapment efficiency (86.67%), drug-loading efficiency (2.33%), morphology, particle size (221.4 nm for uncoated liposomes and 657.7 nm for TMC-coated liposomes), and zeta potential (–9.63 mV for uncoated liposomes and +15.64 mV for TMC-coated liposomes) were investigated. Uncoated CUR liposomes and TMC-coated CUR liposomes showed a similar in vitro release profile. Nearly 50% of CUR was released from liposomes, whereas 80% of CUR was released from CUR propylene glycol solution. CUR incorporated into TMC-coated liposomes exhibited different pharmacokinetic parameters and enhanced bioavailability (Cmax = 46.13 μg/L, t1/2 = 12.05 hours, AUC = 416.58 μg/L·h), compared with CUR encapsulated by uncoated liposomes (Cmax = 32.12 μg/L, t1/2 = 9.79 hours, AUC = 263.77 μg/L·h) and CUR suspension (Cmax = 35.46 μg/L, t1/2 = 3.85 hours, AUC = 244.77 μg/L·h). In conclusion, oral delivery of coated CUR liposomes is a promising strategy for poorly water-soluble CUR.

Advances in clinical study of curcumin.

Curcumin has been estimated as a potential agent for many diseases and attracted great attention owing to its various pharmacological activities, including anti-cancer, and anti-inflammatory. Now curcumin is being applied to a number of patients with breast cancer, rheumatoid arthritis, Alzheimers disease, colorectal cancer, psoriatic, etc. Several clinical trials have stated that curcumin is safe enough and effective. The objective of this article was to summarize the clinical studies of curcumin, and give a reference for future studies.

Formulation Optimization and Bioavailability After Oral and Nasal Administration in Rabbits of Puerarin-Loaded Microemulsion

The main objective of the study was to investigate the efficacy of microemulsion (ME) to facilitate bioavailability of puerarin (PUE) after oral and nasal administration. The pseudo-ternary phase diagrams were constructed to screen the ME components and optimize the ME formulation. The optimized formulation for bioavailability assessment consisted of 20% Tween 80, 20% glycerin, and 1.6% ethyl oleate. The solubility (27.8 mg/mL) of PUE in ME was significantly improved compared to that (4.58 mg/mL) of crude PUE in water. The ME droplets were spherical with a mean particle diameter of 23.4 nm. After nasal (5 mg/kg) and oral (20 mg/kg) administration of a single dose of PUE as ME to fasted rabbits, the absolute bioavailability was 34.58% and 13.54%, respectively. It showed a shorter T(max) (0.75 h) for nasal administration than that (1.0 h) for oral administration of PUE-loaded ME. The C(max) of PUE-loaded ME was 0.55 μg/mL after nasal administration and 0.64 μg/mL after oral administration, respectively. The results showed that nasal administration might be a promising route to enhance the absorption of PUE in the form of ME.

Skin irritation and the inhibition effect on HSV-1 in vivo of penciclovir-loaded microemulsion

The purpose of the present study was to investigate the skin irritation and pharmacodynamics of penciclovir-loaded microemulsion (PCV-ME). The formulation of PCV-ME was comprised of oleic acid (OA) (5%, w/w), Cremorphor EL (20%, w/w), ethanol (30%, w/w) and water (45%, w/w). PCV-ME presented as spherically shaped under transmission electron microscopy with an average diameter of 36.5 nm, and the solubility of PCV in microemulsion (ME) was 7.41 mg/g, almost 6 times that in water. Skin irritation test was performed in male guinea pigs, which demonstrated that no irritation effect was caused after single or multiple applications of PCV-ME. Likewise, male guinea pigs were employed as animal models which were infected with herpes simplex virus type 1 (HSV-1) in pharmacodynamics study. Real-time PCR was utilized to investigate the inhibition effect on HSV-1 exerted by commercial PCV-cream and PCV-ME. The results indicated that compared with commercial PCV-cream, PCV-ME could significantly inhibit the replication of HSV-1 in skin. In conclusion, PCV-ME could be a promising formulation which possessed the virtues of low irritation and high effectiveness.