Improvement in oral bioavailability and dissolution of tanshinone IIA by preparation of solid dispersions with porous silica

Curcumin-loaded soluplus® based ternary solid dispersions with enhanced solubility, dissolution and antibacterial, antioxidant, anti-inflammatory activities

Amorphous solid dispersion (ASD) has emerged to be an outstanding strategy among multiple options available for improving solubility and consequently biological activity. Interestingly several binary SD systems continue to exhibit insufficient solubility over time. Therefore, the goal of current research was to design ternary amorphous solid dispersions (ASDs) of hydrophobic model drug curcumin (CUR) to enhance the solubility and dissolution rate in turn, presenting enhanced anti-bacterial, antioxidant and anti-inflammatory activity. For this purpose several ternary solid dispersions (TSDs) consisting of Soluplus®, Syloid® XDP 3150, Syloid® 244 and Poloxamer® 188 in combination with HPMC E5 (binary carrier) were prepared using solvent evaporation method. Both solubility and dissolution testing of prepared solid dispersion were performed to determine the increase in solubility and dissolution. Solid state investigation was carried out utilizing infrared spectroscopy, also known as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM),Differential scanning calorimetry (DSC) and X-ray diffraction (XRD).Optimized formulations were also tested for their biological effectiveness including anti-bacterial, anti-oxidant and anti-inflammatory activity. Amid all Ternary formulations F3 entailing 20 % soluplus® remarkably improved the solubility (186 μg/ml ± 3.95) and consequently dissolution (91 % ± 3.89 %) of curcumin by 3100 and 9 fold respectively. These finding were also supported by FTIR, SEM, XRD and DSC. In-vitro antibacterial investigation of F3 also demonstrated significant improvement in antibacterial activity against both gram positive (Staphylococcus aureus, Bacillus cereus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. Among all the tested strains Staphylococcus aureus was found to be most susceptible with a zone of inhibition of 24 mm ± 2.87. Antioxidant activity of F3 was also notably enhanced (93 % ± 5.30) in contrast to CUR (69 % ± 4.79). In vitro anti-inflammatory assessment also exhibited that F3 markedly protected BSA (bovine serum albumin) from denaturation with percent BSA inhibition of 80 % ± 3.16 in comparison to CUR (49 % ± 2.91). Hence, F3 could be an effective solid dispersion system for the delivery of model hydrophobic drug curcumin.

Preparation, characterization, oral bioavailability, and pharmacodynamic study of eugenol-porous silica solidified powder

Eugenol possesses anti-inflammatory and antioxidant properties, and may serve as a potential therapeutic agent for hepatic fibrosis. However, the development of solid eugenol formulations is challenging due to its volatility. To address this issue, this study employed porous silica to adsorb solidified eugenol. The solidified powder was characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). In addition, the differences in in vitro release and oral bioavailability between eugenol and solidified eugenol powder were investigated. The effectiveness of eugenol and eugenol powder in treating liver fibrosis was investigated using enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), and histopathological observations. Our results indicate that porous silica can effectively solidify eugenol into powder at a lower dosage. Furthermore, we observed that porous silica accelerates eugenol release in vitro and in vivo. The pharmacodynamic results indicated that eugenol has a positive therapeutic effect against hepatic fibrosis and that porous silica does not affect its efficacy. In conclusion, porous silica was able to solidify eugenol, which may facilitate the preparation and storage of solid formulations.

Application of commercially available mesoporous silica for drug dissolution enhancement in oral drug delivery

Due to the high number of poorly water-soluble active pharmaceutical ingredients, oral drug delivery development has become challenging. One of the strategies to enhance drug solubility and to achieve high oral bioavailability is to formulate such compounds into amorphous solid dispersions. In recent years, porous materials have been investigated as possible carriers into which a drug can be adsorbed, such as mesoporous silica, in particular. Unlike the ordered mesoporous network of silica, non-ordered silica already has a "generally regarded as safe" status, and is already used as an excipient in pharmaceutical and cosmetic products. Thus, it is reasonable to expect that products that contain solid dispersions with non-ordered carriers will reach the market sooner and more easily than those with ordered mesoporous carriers. The emphasis of this review is therefore on non-ordered commercially available mesoporous silica and the progress that has been made in development of the use of these materials for improved dissolution rates in oral drug delivery. First, a thorough categorisation of the drug loading methods is presented, followed by discussion on the most important characteristics of solid dispersions (i.e., physical state, stability, drug release). Finally, manufacturability and production of a final solid dosage form are considered.

PEI-PEG-Coated Mesoporous Silica Nanoparticles Enhance the Antitumor Activity of Tanshinone IIA and Serve as a Gene Transfer Vector

Tanshinone IIA (TanIIA) and gene therapy both hold promising potentials in hepatocellular carcinoma (HCC) treatment. However, low solubility and poor bioavailability of TanIIA limit its clinical application. Similarly, gene therapy with GPC3-shRNA, a type of short hairpin RNAs (shRNAs) capable of silencing the glypican-3 (GPC3) expression, is seriously limited due to its susceptibility to nuclease degradation and high off-target effects. In the present study, polyethyleneimine (PEI)-polyethylene glycol (PEG)-coated mesoporous silica nanoparticles (MSN-PEG) were used as a drug carrier. By encapsulating TanIIA into MSN-PEG, we synthesized MSN-TanIIA-PEG nanoparticles and observed the involved characteristics. This was followed by exploration of antitumor activity on the HepG2 cell lines in vitro. Meanwhile, in order to construct GPC3-shRNA plasmids, a shRNA sequence targeting GPC3 was synthesized and cloned into the pSLenti-U6 vector. Accordingly, the performance of MSN-PEG as a gene transfer carrier for GPC3-shRNA gene therapy of HCC in vitro was evaluated, including transfection efficiency and DNA binding biological characteristics. The results indicated successful encapsulation of TanIIA in MSN-PEG, which had satisfactory efficacy, favorable dispersity, suitable particle size, and sustained release effect. The in vitro anti-HCC effects of nano-TanIIA were greatly improved, which outperformed free-TanIIA in terms of proliferation and invasion inhibition, as well as apoptosis induction of HCC cells. As expected, MSN-PEG possessed excellent gene delivery capacity with good binding, release, and protection from RNase digestion. Using MSN-PEG as a gene carrier, the plasmids were successfully transfected into HepG2 cells, and both the mRNA and protein expressions of GPC3 were significantly downregulated. It was thus concluded that a sustained release TanIIA delivery system for HCC treatment was synthesized and that MSN-PEG could also serve as a gene transfer carrier for gene therapy. More interestingly, MSN-PEG may be a potential delivery platform that combines TanIIA and GPC3-shRNA together to enhance their synergistic effect.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

Improved transdermal permeability of tanshinone IIA from cataplasms by loading onto nanocrystals and porous silica

Novel transdermal cataplasms have been designed to improve permeability of poorly soluble drugs by different pretreatments. Nanocrystal and porous silica solid dispersions were loaded with Tanshinone IIA and incorporated into a cross-linked hydrogel matrix of cataplasm. It was shown that the small particle size and improved dissolution would increase dermal bioavailability. The adhesion, rheological properties, drug release, skin permeation, skin deposition and in vivo skin absorption of the different formulations were investigated. In an in vitro experiment using mouse skin, cumulative amount of drug permeated within 24 h was 7.32 ± 0.98 μg/cm² from conventional cataplasm, 13.14 ± 0.70 μg/cm² from nanocrystal-loaded cataplasm and 11.40 ± 0.13 μg/cm² from porous silica solid dispersion-loaded cataplasm. In vitro dissolution profiles showed that drug release was 76.5% and 74.9% from two optimized cataplasms within 24 h, while conventional cataplasm was 55.0%. The cross-linking characteristics of the cataplasms were preserved after incorporation of different drug forms, while the elastic and viscous behaviors of the hydrogel layers increased. In vivo evaluation by CLSM showed the more favorable skin permeation for two optimized cataplasms. These findings suggest that applications of nanocrystal and porous silica systems on cataplasms enable effective transdermal delivery of poorly soluble drugs. The resulting drug delivery and rheological properties are desirable for transdermal application.AbbreviationAll the abbreviations that appear in this article are shown in Table 1.

Enhanced oral bioavailability of Tanshinone IIA using lipid nanocapsules: Formulation, in-vitro appraisal and pharmacokinetics

Tanshinone IIA (TSIIA) is a promising phytomedicine that has been extensively studied due to its numerous biological activities, especially as an anticancer drug. However, it suffers from poor oral bioavailability owing to low aqueous solubility, poor permeability and exposure to first-pass metabolism. This study endeavored to improve TSIIA oral bioavailability by encapsulation into lipid nanocapsules (LNCs) for the first time. A previously reported phase-inversion method was used to prepare Tanshinone II A loaded LNCs (TSIIA-LNCs) with slight modifications based on a constructed phase diagram. They were then in-vitro characterized and their oral pharmacokinetics were studied in rats. TSIIA-LNCs showed excellent colloidal properties (size; 70 nm, PDI < 0.2 and zeta-potential; -13.5 mV), a high percent entrapment efficiency (98%) and a good drug payload (2.6 mg/g). Furthermore, the in-vivo pharmacokinetic study revealed a significant enhancement in both the rate and extent of absorption of TSIIA-LNCs compared with TSIIA suspension with about 3.6-fold increase in AUC _0-inf value (p ≤ 0.01). Additionally, a significant increase in both half-life and mean residence time was exhibited by TSIIA-LNCs (p ≤ 0.01), confirming their long circulating properties. Therefore, the elaborated LNCs could be addressed as a promising nanoplatform permitting higher TSIIA oral bioavailability.

Glabridin smartPearls - Silica selection, production, amorphous stability and enhanced solubility

Glabridin, a compound in the root extract of Glycyrrhiza glabra, has been identified as an effective tyrosinase inhibitor. Applied on skin, melanin synthesis is inhibited, making glabridin an interesting candidate for skin whitening or for the treatment of age spots. However, main obstaclefor its practical use is its low dermal bioavailability, caused by its poor water solubility. In this work smartPearls technology was used to increase the glabridins water solubility. smartPearls consist of silica particles with mesopores in which actives can be loaded. By this, actives are stabilized in amorphous state and simultaneously finely distributed in nm-range. Both amorphization and nanoization are well known approaches to increase saturation solubilities. In smartPearls these approaches are combined. In the first step, glabridin smartPearls formulation was developed, screening systematically the suitability of 4 different silicas varying in their pore sizes (3, 6, 10, 17 nm). Also, most suited filling level of glabridin was determined (25, 50, 80% referred to total pore volume of respective silica). Silica loading was performed by the immersion-evaporation method, resulting in pores filled with glabridin from bottom to top. By light microscopy, dynamic scanning calorimetry and X-ray diffraction the sample with 6 nm pore size and filling levels of 25% and 50% have been verified to be completely amorphous. Highest physical storage stability of 7 months up to now was obtained for the 25% filled sample. In the next step, concept of increased saturation solubility for smartPearls was proven. Dissolution profiles were recorded in situ for glabridin smartPearls and compared to glabridin raw drug powder. Both saturation solubility and dissolution velocity were remarkably improved. The water solubility for example increased by a factor of more than 4. This makes glabridin smartPearls promising for creating skin products with improved dermal bioavailability.

Development on porous particles of Pueraria lobatae Radix for improving its compactibility and dissolution

Herein, we report a study on the influence of particles having different porosities on tablet performance. The ethanol extract of Pueraria lobatae Radix (EPL) was chosen as the model drug. A series of porous EPL particles were prepared by co-spray drying EPL with different amounts of ammonium bicarbonate (NH4HCO3), and their powder properties (particle morphology, particle size, porosity, flowability, bulk density, and tap density) and tablet properties (tensile strength, E sp, yield pressure, dissolution, etc.) were comparatively investigated. The results showed that there were significant differences in the fundamental and functional properties of the spray-dried and parent EPLs. First, the irregular and dense primary EPL particles were transformed into loose, hollow, and spheroidal particles via co-spray drying with NH4HCO3. Second, compared to parent EPL, porous EPLs showed a significant improvement (1.80-7.03 times) in compactibility. Third, the dissolution rates of porous EPLs were similar, and all were more than twice as fast as that of parent EPL. The increased porosity, on the one hand, led to the increase in interparticle and intraparticle bonding forces during tableting and, on the other hand, facilitated water intrusion into tablets for disintegration and dissolution. Porous particle design is therefore promising, especially for drugs with both poor compactibility and dissolution.

Design and pharmaceutical applications of porous particles

Porous particles have been developed as a novel carrier to improve drug delivery, dissolution, tableting, and so on, which can be prepared by many methods.

Tanshinones and mental diseases: from chemistry to medicine

The prevalence of mental diseases, especially neurodegenerative disorders, is ever-increasing, while treatment options for such disorders are limited and insufficient. In this scarcity of available medication, it is a feasible strategy to search for potential drugs among natural compounds, such as those found in plants. One such plant source is the root of Chinese sage, Salvia miltiorrhiza Bunge (Labiatae), which contains several compounds reported to possess neuroprotective activities. The most important of these compounds are tanshinones, which have been reported to possess ameliorative activity against a myriad of mental diseases such as Alzheimer’s disease, cerebral ischemia/reperfusion injury, and glioma, along with promoting neuronal differentiation and manifesting antinociceptive and anticonvulsant outcomes. This review offers a critical evaluation of the utility of tanshinones to treat mental illnesses, and sheds light on the underlying mechanisms through which these naturally occurring compounds confer neuroprotection.

Preparation and tableting of long-term stable amorphous rutin using porous silica

Amorphous state of drugs increases the oral bioavailability, but typically faces physical stability problems. Amorphous rutin was generated and physically stabilized by encapsulating inside mesopores of porous AEROPERL® 300 Pharma and named as rutin CapsMorph® in this study. AEROPERL® 300 Pharma was loaded with rutin dissolved in DMSO containing Tween 80, and subsequently the solvent evaporated (wetness impregnation method). The loading process was monitored by light microscopy and scanning electron microscopy (SEM). X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to confirm the amorphous state in AEROPERL® 300 Pharma. A loading of 20% of the rutin-AEROPERL® 300 Pharma mixture was obtained. The amorphous state proved to be stable over 2years of storage at room temperature. Due to the amorphous state and the nanosize of the rutin in the mesopores, the kinetic saturation solubility increased to about 4mg/ml (water, 0.1MHCl, pH 6.8PBS) compared to the maximum observed thermodynamic equilibrium solubility of rutin raw drug powder of only 74.48±1.42μg/ml in pH 6.8PBS (=increase by factor about 54). The dissolution velocity also increased distinctly, e.g. about 96.1% of rutin dissolution from CapsMorph® powder in water within 5min compared to less than 40% of raw drug powder after 3h. Tablets were produced with rutin CapsMorph®, raw drug powder and their dissolution velocity compared to a marketed product. About 83.0-95.6% were released from the rutin CapsMorph® tablet within 5min, compared to 42.7-52.5% from the marketed tablet after 3h (water, 0.1MHCl, pH 6.8PBS). After dissolution the supersaturation level of rutin CapsMorph® remained over about 2h, then solubility slowly reduced, but remained after 48h still multifold above the thermodynamic rutin solubility. This should be sufficient for many poorly soluble drugs to achieve a sufficient bioavailability. For optimal exploitation of the supersaturation, a multiple step release system could be used, e.g. release of CapsMorph® particles every 2-3h.