Caleb Kesse Firempong

Enhanced oral bioavailability and in vivo antioxidant activity of chlorogenic acid via liposomal formulation.

In the present study, a formulation system consisting of cholesterol and phosphatidyl choline was used to prepare an effective chlorogenic acid-loaded liposome (CAL) with an improved oral bioavailability and an increased antioxidant activity. The developed liposomal formulation produced regular, spherical and multilamellar-shaped distribution nanoparticles. The pharmacokinetic analysis of CAL compared with chlorogenic acid (CA), showed a higher value of Cmax(6.42 ± 1.49 min versus 3.97 ± 0.39 min) and a delayed Tmax(15 min versus 10 min), with 1.29-fold increase in relative oral bioavailability. The tissue distribution in mice also demonstrated that CAL predominantly accumulated in the liver which indicated hepatic targeting potential of the drug. The increased activities of antioxidant enzymes (Total Superoxide Dismutase (T-SOD) and Glutathione Peroxidase (GSH-Px)) and total antioxidant capacity (T-AOC), in addition to decreased level of malondialdehyde (MDA) in CCl4-induced hepatotoxicity study further revealed that CAL exhibited significant hepatoprotective and antioxidant effects. Collectively, these findings present a liposomal formulation with significantly improved oral bioavailability and an increased in vivo antioxidant activity of CA.

Enhanced oral bioavailability and tissue distribution of a new potential anticancer agent, Flammulina velutipes sterols, through liposomal encapsulation.

This study innovatively investigated the anticancer effect of Flammulina velutipes sterols (FVSs), the in vivo pharmacokinetics, and the tissue distribution of FVS-loaded liposomes. The FVS consisting of mainly 54.8% ergosterol and 27.9% 22,23-dihydroergosterol exhibited evident in vitro antiproliferative activity (liver HepG-2, IC50 = 9.3 μg mL(-1); lung A549, IC50 = 20.4 μg mL(-1)). To improve the poor solubility of FVS, F. velutipes sterol liposome (FVSL) was originally prepared. The encapsulation efficiency of ergosterol was 71.3 ± 0.1% in FVSL, and the encapsulation efficiency of 22,23-dihydroergosterol was 69.0 ± 0.02% in FVSL. In comparison to its two free sterol counterparts, the relative bioavailability of ergosterol and 22,23-dihydroergosterol in FVSL was 162.9 and 244.2%, respectively. After oral administration in Kunming mice, the results of tissue distribution demonstrated that the liposomal FVS was distributed mostly in liver and spleen. The drug was eliminated rapidly within 4 h. These findings support the fact that FVS, a potential nutraceutical and an effective drug for the treatment of liver cancer, could be encapsulated in liposomes for improved solubility and bioavailability.

Enhanced oral bioavailability of a sterol-loaded microemulsion formulation of Flammulina velutipes, a potential antitumor drug

Purpose To investigate the growth inhibition activity of Flammulina velutipes sterol (FVS) against certain human cancer cell lines (gastric SGC and colon LoVo) and to evaluate the optimum microemulsion prescription, as well as the pharmacokinetics of encapsulated FVS. Methods Molecules present in the FVS isolate were identified by gas chromatography/mass spectrometry analysis. The cell viability of FVS was assessed with methyl thiazolyl tetrazolium (MTT) bioassay. Based on the solubility study, phase diagram and stability tests, the optimum prescription of F. velutipes sterol microemulsions (FVSMs) were determined, followed by FVSMs characterization, and its in vivo pharmacokinetic study in rats. Results The chemical composition of FVS was mainly ergosterol (54.8%) and 22,23-dihydroergosterol (27.9%). After 72 hours of treatment, both the FVS (half-maximal inhibitory concentration [IC50] = 11.99 μg · mL−1) and the standard anticancer drug, 5-fluorouracil (IC50 = 0.88 μg · mL−1) exhibited strong in vitro antiproliferative activity against SGC cells, with IC50 > 30.0 μg · mL−1; but the FVS performed poorly against LoVo cells (IC50 > 40.0 μg · mL−1). The optimal FVSMs prescription consisted of 3.0% medium chain triglycerides, 5.0% ethanol, 21.0% Cremophor EL and 71.0% water (w/w) with associated solubility of FVS being 0.680 mg · mL−1 as compared to free FVS (0.67 μg · mL−1). The relative oral bioavailability (area-under-the-curve values of ergosterol and 22,23-dihydroergosterol showed a 2.56-fold and 4.50-fold increase, respectively) of FVSMs (mean diameter ~ 22.9 nm) as against free FVS were greatly enhanced. Conclusion These results indicate that the FVS could be a potential candidate for the development of an anticancer drug and it is readily bioavailable via microemulsion formulations.

In vitro and in vivo evaluation of capsaicin‐loaded microemulsion for enhanced oral bioavailability

BACKGROUND Capsaicin, as a food additive, has attracted worldwide concern owing to its pungency and multiple pharmacological effects. However, poor water solubility and low bioavailability have limited its application. This study aims to develop a capsaicin-loaded microemulsion to enhance the oral bioavailability of the anti-neuropathic-pain component, capsaicin, which is poorly water soluble. RESULTS In this study, the microemulsion consisting of Cremophor EL, ethanol, medium-chain triglycerides (oil phase) and water (external phase) was prepared and characterized (particle size, morphology, stability and encapsulation efficiency). The gastric mucosa irritation test of formulated capsaicin was performed in rats to evaluate its oral feasibility, followed by the pharmacokinetic study in vivo. Under these conditions, the encapsulated capsaicin revealed a faster capsaicin release in vitro coupled with a greater absorption in vivo when compared to the free capsaicin. The oral bioavailability of the formulated capsaicin-loaded microemulsions was 2.64-fold faster than that of free capsaicin. No significant irritation was observed on the mucosa from the pathological section of capsaicin-loaded microemulsion treated stomach. CONCLUSION These results indicate that the developed microemulsion represents a safe and orally effective carrier for poorly soluble substances. The formulation could be used for clinical trials and expand the application of capsaicin.

Hypolipidemic potential of perillaldehyde-loaded self-nanoemulsifying delivery system in high-fat diet induced hyperlipidemic mice: Formulation, in vitro and in vivo evaluation

This study reports the hypolipidemic effects of perillaldehyde-loaded self-nanoemulsifying delivery system (PAH-SNEDS) developed with D-optimal experimental design based on a three component system: 40% w/w drug-oil phase, X1 (a mixture of perillaldehyde-isopropyl myristate/medium chain triglyceride, 1:1, w/w); 48% surfactant, X2 (Kolliphor EL); and 12% co-surfactant, X3 (PEG 200). The design space was navigated using a linear model to produce spherical and homogenous droplets which were observed under TEM, with mean size, polydispersity index (PDI) and zeta potential of 32.8 ± 0.1 nm, 0.270 ± 0.029 and -10.14 ± 0.66 mV, respectively. PAH-SNEDS demonstrated significant increase in dissolution in vitro compared to the free PAH, and further yielded an oral relative bioavailability of about 206.18% in vivo which suggested a promising formulation design for potential liquid bioactive compounds. Oral administration of PAH-SNEDS (240 mg/kg per body weight) in high-fat induced hyperlipidemia in mice, also significantly decreased serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) while increasing high-density lipoprotein cholesterol (HDL-C) level. The improved bioavailability and functional application of PAH via SNEDDS suggested a suitable approach to promote hypolipidemic effect of the drug. Perillaldehyde, therefore, promises to be a useful bioactive compound to prevent high-fat diet induced hyperlipidemia.

Preparation, characterization, and pharmacokinetics study of capsaicin via hydroxypropyl-beta-cyclodextrin encapsulation

Abstract Context: Capsaicin (CAP) is an effective drug in the treatment of pain and cancer. However, its practical administration has been limited due to poor aqueous solubility and bioavailability, as well as strong gastrointestinal irritation. Objective: The objective of this study is to improve the solubility and oral bioavailability of CAP by reducing irritation via hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex formulation, in vitro and in vivo analysis. Materials and methods: The complex (CAP-HP-β-CD) was developed via the magnetic stirring method and characterized using ultraviolet (UV) absorption spectrometry, infrared radiation (IR) spectroscopy, and differential scanning calorimetry (DSC). Rats were treated with CAP (90 mg × kg−1) or CAP-HP-β-CD (corresponding to 90 mg × kg−1 CAP) by gavage, and all the plasma samples were analyzed with high performance liquid chromatography (HPLC). Results: The results of UV, IR, and DSC showed that an acceptable CAP-HP-β-CD (encapsulation efficiency, 75.83%; drug loading, 7.44%) was formulated. In vitro release study of CAP-HP-β-CD revealed that the cumulative release of CAP from HP-β-CD encapsulation was obviously enhanced (above 80% increases). Similarly, the in vivo pharmacokinetics parameters also increased, Cmax (from 737.94 to 1117.57 ng × mL−1), AUC0– (from 5285.9 to 7409.8 ng × h × mL−1) or relative bioavailability (139.38%). The gastric irritation bioassay further showed that the CAP-HP-β-CD was far better than free CAP. Discussion and conclusion: CAP exhibited significant aqueous solubility and oral bioavailability, as well as minimal irritation effect after forming inclusion complex with HP-β-CD. Therefore, these findings could provide an equally important alternative option for the clinical use of CAP.

Cytotoxic effect of novel Flammulina velutipes sterols and its oral bioavailability via mixed micellar nanoformulation.

The aim of this study was to investigate the anti-tumor effect of sterols initially separated from Flammulina velutipes and the pharmacokinetics and tissue distribution after oral administration of F. velutipes sterol nanomicelles (FVSNs). F. velutipes sterol (FVS) consisted of mainly ergosterol (54.78%), 22,23-dihydroergosterol (27.94%) and ergost-8(14)-ene-3β-ol (discovered for the first time in F. velutipes). In vitro cytotoxicity assay of FVS against U251 cells and HeLa cells showed that at 72h treatment, the FVS (IC50=23.42μg/mL) exhibited strong inhibitory effect against U251 cells, even overwhelmed the standard anti-tumor drug (5-fluorouracil) to an extent, while the HeLa cells were not significantly susceptible to the FVS. To improve the solubility and bioavailability of FVS, a model for insoluble anti-tumor drugs, FVSNs were prepared. In vitro characterization of FVSNs revealed satisfactory size distribution, loading capacity and encapsulation efficiency. Pharmacokinetic study in SD rats demonstrated that the mixed micellar nanoformulation significantly enhanced the bioavailability of FVS than free drug. Additionly, tissue distribution in mice manifested that the biodistribution of FVSNs as compared to the free FVS suspension were significantly improved. In conclusion, the nanomicelles developed in our study provided a promising delivery system for enhancing the oral bioavailability and selective biodistribution of FVS, a potential anti-tumor agent.

Ergosterol-loaded poly(lactide-co-glycolide) nanoparticles with enhanced in vitro antitumor activity and oral bioavailability.

Aim:Ergosterol is a plant sterol with anti-tumor and anti-angiogenic activities, but is poorly soluble. In this study, we attempted to enhance its anti-tumor action and oral bioavailability via poly(lactide-co-glycolide) (PLGA) nanoparticle encapsulation.Methods:Ergosterol-loaded PLGA nanoparticles (NPs/Erg) were prepared using the emulsion/solvent evaporation technique. Their physicochemical properties were characterized, and their cytotoxicity against human cancer cell lines was evaluated with MTT assay. The pharmacokinetics and tissue distribution of NPs/Erg were investigated in rats and mice, respectively.Results:NPs/Erg were spherical in shape with a particle size of 156.9±4.8 nm and a Zeta potential of -19.27±1.13 mV, and had acceptable encapsulation efficiency and loading capacity. NPs/Erg exerted much stronger cytotoxicity against human cancer cells than the free ergosterol, and showed significantly reduced IC50 values (14.69±0.48 μg/mL in glioma U251 cells; 9.43±0.52 μg/mL in breast cancer MCF-7 cells; 4.70±0.41 μg/mL in hepatoma HepG2 cells). After oral administration of a single dose in rats, NPs/Erg displayed a prolonged plasma circulation with a 4.9-fold increase of oral bioavailability compared with the free ergosterol. After mice received NPs/Erg, the ergosterol in NPs/Erg was rapidly distributed in stomach, kidneys, liver, brain, spleen, and virtually non-existent in heart and lungs. The presence of NPs/Erg in brain was particularly improved compared with the free ergosterol.Conclusion:The PLGA nanoparticles serve as a promising carrier for the poorly soluble ergosterol and significantly improve its bioavailability, biodistribution and in vitro anti-tumor activities.

Lipid Raft Stationary Phase Chromatography for Screening Anti-tumor Components from Galla chinensis

For the first time, a novel biological affinity separating system called lipid raft stationary phase chromatography (LRSC) was developed. It was employed to screen bioactive components from Chinese gallnut, a traditional Chinese medicine (TCM). The LRSC was prepared by the addition of activated silica to Tris–HCl solution, which contains the isolated lipid rafts of U251 cells. This was followed by agitation, washing, centrifugation and then re-suspension of the residue in another Tris–HCl solution. The lipid rafts possess abundant receptor tyrosine kinase, specifically tropomyosin-related kinase A (TrkA), which is a widely researched anti-tumor drug target. Thus, TrkA provided the LRSC model with the ability to select fractions that specifically interact with it. Using a non-TrkA targeted anti-tumor drug (gemcitabine) and TrkA targeted anti-tumor drugs (lestaurtinib and gefitinib) as controls to evaluate the specific affinity of the LRSC column, the different fractions of Chinese gallnut were subjected to LRSC screening for the identification of anti-tumor components. As a result, the ether fraction of Chinese gallnut manifested desirable affinity properties. The methyl thiazolyl tetrazolium assay confirmed the anti-tumor effect of the screened ether fraction, and more importantly, the ether fraction failed woefully to exhibit its anti-proliferative activity in the presence of TrkA inhibitors (K252a and primary antibody). This further proves the selectivity of LRSC on TrkA-targeted drugs. The LRSC model has, therefore, shown to be of high efficiency and selectivity in screening bioactive components from the complex TCM extracts, thus offering an effective approach for the development of anticancer natural products.

Preparation, characterization and pharmacokinetic studies of linalool-loaded nanostructured lipid carriers

Abstract Context Linalool (LL) is associated with numerous pharmacological activities. However, its poor solubility usually results in poor bioavailability, and further limited its applications. Objective To reduce volatilization and improve bioavailability of LL, linalool-loaded nanostructured lipid carriers (LL-NLCs) were prepared. Materials and methods LL-NLCs were prepared using high-pressure homogenization method and optimized via response surface methodology-central composite design, followed by characterization, including particle size (PS), zeta potential (ZP), transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and in vitro release study. Rats were administered 300 mg × kg − 1 LL with each preparation (LL-NLCs or LL) via oral gavage. Results LL-NLCs had a PS of 52.72 nm with polydispersity index of 0.172, and ZP of –16.0 mV. The encapsulation efficiency and drug loading gave 79.563 and 7.555%, respectively. The cumulative release of LL from free LL reached 51.414% at 180 min, while LL from LL-NLCs was 15.564%. All the pharmacokinetics parameters of LL-NLCs were better than those of LL, including Cmax (from 1915.45 to 2182.45 ng × mL − 1), AUC0–t (from 76003.40 to 298948.46 ng × min × mL − 1) and relative bioavailability (393.34%). The t1/2, MRT and tmax of LL-NLCs (110.50, 146.66 and 60 min) were also longer than that of LL (44.72, 45.66 and 40 min). Discussion and conclusion LL-NLCs were for the first time prepared and its oral administration in rats thoroughly investigated. LL-NLCs exhibited sustained release effect and increased absorption of LL. Therefore, these findings might provide a potential possibility for clinical application of LL.