A novel solid dispersion system for natural product-loaded medicine: silymarin-loaded solid dispersion with enhanced oral bioavailability and hepatoprotective activity

Synthesis, physiochemical characterization, molecular docking study, and anti-breast cancer activity of silymarin loaded zein nanoparticles

Breast cancer is a major cause of death in women worldwide leading to requirement of new therapeutic strategies. Silymarin demonstrated the anti-cancer activity however, due to low bioavailability its use is restricted. This study aimed to improve the solubility of silymarin by developing a silymarin loaded zein nanoparticles (SLNPs) which was stabilized by beta cyclodextrin. Comprehensive physiochemical characterization studies based on DLS, FTIR, UV-Vis Spectroscopy, FE-SEM, TEM, XRD, DSC, NMR and TGA confirmed the successful synthesis of SLNPs via an anti-solvent precipitation method. FE-SEM and TEM images demonstrated the uniform size and spherical shape of nanoparticles with encapsulation and loading efficiencies of 84.32 ± 1.9 % and 15.25 ± 2.4 % respectively. The zein protein interaction with silymarin, and β-cyclodextrin was shown to be beneficial via the use of molecular simulations and binding energy calculations. Cellular studies demonstrated dose and time dependent cytotoxicity of SLNPs on MCF-7 breast cancer cell. FACS, qRT-PCR and Western blotting showed Bax (pro-apoptotic) upregulation while Bcl-2 (anti-apoptotic) downregulation. Our findings suggest that these loaded nanoparticles are more efficient than pure drug, enhancing its bioavailability and paving the path for developing it as a promising nutraceutical to treat breast cancer.

Formulation of silymarin binary and ternary solid dispersions: Characterization, simulation study and cell viability assessment against lung cancer cell line

Silymarin (SL) is a water-insoluble flavonoid used in the treatment of different diseases, but its therapeutic activity is limited due to its low solubility. So, in the present study, SL solid dispersions (SDs) were developed using different carriers like Kollidone VA64 (KL), Soluplus (SP), and Poloxamer 188 (PL) by solvent evaporation (SE), microwave irradiation (MI), and freeze-drying (FD) methods. The phase solubility and saturation solubility studies were assessed to estimate the stability constant as well as the carrier effect. The dissolution studies were performed for prepared SL-SDs (binary and ternary) to select the optimum SL-SDs. The selected SL-SDs (F5, F9) were further characterized for infrared spectroscopy (IR), nuclear magnetic resonance (NMR), differential scanning calorimeter (DSC), scanning electron microscope (SEM), and X-ray diffraction (XRD). Finally, the comparative cell viability assay (lung cancer cell line) was performed to evaluate the change in activity after the formulation of SDs. The phase solubility and solubility study results displayed marked enhancements in solubility. The dissolution study findings showed significant enhancement in drug release from ternary solid dispersions (F7-F9) > ternary physical mixture (PM3) > binary solid dispersions (F1-F6) > binary physical mixture (PM1, PM2) in comparison to free SL. A greater release was observed from ternary SDs due to the addition of PL in the formulation, which had a synergistic effect on increasing the solubility. IR and NMR spectra revealed no chemical interaction between SL, KL, and PL. DSC, XRD, and SEM all confirmed the transformation of crystalline SL into amorphous SL. The cell viability assay demonstrated significantly enhanced results from ternary solid dispersion (F9) compared to free SL. Based on the study results, it can be said that SL-SDs are an alternative way to deliver drugs orally that can improve solubility and have anti-cancer activity.

Quality by design-based development and optimization of fourth-generation ternary solid dispersion of standardized Piper longum extract for melanoma therapy

The study aimed to enhance the solubility, dissolution, and oral bioavailability of standardized Piper longum fruits ethanolic extract (PLFEE) via fourth-generation ternary solid dispersion (SD) for melanoma therapy. With the use of solvent evaporation method, the standardized PLFEE was formulated into SD, optimized using Box-Wilson's central composite design (CCD), and evaluated for pharmaceutical performance and in vivo anticancer activity against melanoma (B16F10)-bearing C57BL/6 mice. The optimized SD showed good accelerated stability, high yield, drug content, and content uniformity for bioactive marker piperine (PIP). The X-ray diffraction (XRD), differential scanning calorimetry (DSC), polarized light microscopy (PLM), and selected area electron diffraction (SAED) analysis revealed its amorphous nature. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and high-performance thin layer chromatography (HPTLC) revealed the compatibility of excipients with the PLFEE. The contact angle measurement and in vitro dissolution study revealed excellent wetting of SD and improved dissolution profile as compared to the plain PLFEE. The in vivo oral bioavailability of SD reflected a significant (p < 0.05) improvement in bioavailability (Frel = 188.765%) as compared to plain extract. The in vivo tumor regression study revealed the improved therapeutic activity of SD as compared to plain PLFEE. Further, the SD also improved the anticancer activity of dacarbazine (DTIC) as an adjuvant therapy. The overall result revealed the potential of developed SD for melanoma therapy either alone or as an adjuvant therapy with DTIC.

Pharmaceutical prospects of Silymarin for the treatment of neurological patients: an updated insight

Background

Silymarin is a polyphenolic flavonoid complex extricated from dried fruits and seeds of the plant Silybum marianum L. Chemically, it is a mixture of flavonolignan complexes consisting of silybin, isosilybin, silychristin, silydianin, a minor quantity of taxifolin, and other polyphenolic compounds, which possess different bio medicinal values.

Purpose

This review critically looks into the current status, pharmaceutical prospects and limitations of the clinical application of Silymarin for treating neurological disorders. In particular, Silymarin's medicinal properties and molecular mechanisms are focused on providing a better-compiled understanding helpful in its neuro-pharmacological or therapeutic aspects.

Methods

This review was compiled by the literature search done using three databases, i.e., PubMed (Medline), EMBASE and Science Direct, up to January 2023, using the keywords-Silymarin, neurological disorders, cognitive disorders, Type 2 Diabetes, pharmaceutical prospects and treatment. Then, potentially relevant publications and studies (matching the eligible criteria) were retrieved and selected to explain in this review using PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) study flow chart.

Result

Since its discovery, it has been widely studied as a hepatoprotective drug for various liver disorders. However, in the last 10-15 years, several research studies have shown its putative neuroprotective nature against various brain disorders, including psychiatric, neurodegenerative, cognitive, metabolic and other neurological disorders. The main underlying neuroprotective mechanisms in preventing and curing such disorders are the antioxidant, anti-inflammatory, anti-apoptotic, pro-neurotrophic and pro-estrogenic nature of the bioactive molecules.

Conclusion

This review provides a lucid summary of the well-studied neuroprotective effects of Silymarin, its underlying molecular mechanisms and current limitations for its usage during neurological disorders. Finally, we have suggested a future course of action for developing it as a novel herbal drug for the treatment of brain diseases.

Solid dispersion technology as a formulation strategy for the fabrication of modified release dosage forms: A comprehensive review

Solubility limited bioavailability is one of the crucial parameters that affect the formulation development of the new chemical entities. Thus the major constraint in the pharmaceutical product development is the suitable solubility enhancement technique for Active Pharmaceutical Ingredient. Solid dispersion (SD) is an established and preferred method for improving the solubility which ultimately may be helpful to enhance bioavailability. For long period of time Amorphous solid dispersion (ASD) have been preferred for improving solubility, but since last two decades, ASD approach have been combined with different modified release approaches to improvise the stability and site specificity of SD to grasp a hold over the specific advantages associated with such dosage forms. It is an established fact now that the SD technique not only improves solubility limited bioavailability, but it may be combined with other approaches to modify the drug release profile from the formulation as per the requirement based on the apt selection of SD carriers and suitable technology. This review covers the comprehensive overview of all such formulations where SD technology is used to serve dual purpose rather than only the sole purpose of solubility enhancement. The SD approach has been successfully implemented for some of the poorly soluble herbal drugs and still there is a vast scope of advancement in that area. The current review will provide a broad outcome in the area of SD technology for modified release formulations along with the description of current status and future prospective of SD. The SD formed by dispersing drug within the conventional carrier to form ASD increases solubility, dissolution rate and bioavailability; whereas fourth generation hydrophobic carriers provide added advantage of controlled release (CR) or sustained release (SR) profile along with enhanced stability of SD. On the other frontier, pH dependant carriers enable the SD to achieve site specificity or delayed release (DR) profile.

Improved Hygroscopicity and Bioavailability of Solid Dispersion of Red Ginseng Extract with Silicon Dioxide

This study aims to develop a powder formulation for the Korean red ginseng extract (RGE) and to evaluate its in vitro and in vivo formulation characteristics. The solid dispersion of RGE was prepared with hydrophilic carriers using a freeze-drying method. After conducting the water sorption–desorption isothermogram (relative humidity between 30 and 70% RH), differential scanning calorimetry thermal behavior, dissolution test, and intestinal permeation study, a solid dispersion formulation of RGE and silicon dioxide (RGE-SiO₂) was selected. RGE-SiO₂ formulation increased intestinal permeability of ginsenoside Rb1 (GRb1), GRb2, GRc, and GRd by 1.6-fold in rat jejunal segments as measured by the Ussing chamber system. A 1.6- to 1.8-fold increase in plasma exposure of GRb1, GRb2, GRc, and GRd in rats was observed following oral administration of RGE-SiO₂ (375 mg/kg as RGE). No significant difference was observed in the time to reach maximum concentration (T_max) and half-life in comparison to those in RGE administered rats (375 mg/kg). In conclusion, formulating solid dispersion of RGE with amorphous SiO₂, the powder formulation of RGE was successfully formulated with improved hygroscopicity, increased intestinal permeability, and enhanced oral bioavailability and is therefore suitable for processing solid formulations of RGE product.

Systematic review of pharmacokinetics and potential pharmacokinetic interactions of flavonolignans from silymarin

Silymarin is an extract from the seeds (fruits) of Silybum marianum that contains flavonolignans and flavonoids. Although it is frequently used as a hepatoprotective agent, its application remains somewhat debatable, in particular, due to the low oral bioavailability of flavonolignans. Moreover, there are claims of its potential interactions with concomitantly used drugs. This review aims at a systematic summary and critical assessment of known information on the pharmacokinetics of particular silymarin flavonolignans. There are two known major reasons for poor systemic oral bioavailability of flavonolignans: (1) rapid conjugation in intestinal cells or the liver and (2) efflux of parent flavonolignans or formed conjugates back to the lumen of the gastrointestinal tract by intestinal cells and rapid excretion by the liver into the bile. The metabolism of phase I appears to play a minor role, in contrast to extensive conjugation and indeed the unconjugated flavonolignans reach low plasma levels after common doses. Only about 1%-5% of the administered dose is eliminated by the kidneys. Many in vitro studies tested the inhibitory potential of silymarin and its components toward different enzymes and transporters involved in the absorption, metabolism, and excretion of xenobiotics. In most cases, effective concentrations are too high to be relevant under real biological conditions. Most human studies showed no silymarin-drug interactions explainable by these suggested interferences. More interactions were found in animal studies, likely due to the much higher doses administered.

Enhanced Bioavailability and Efficacy of Silymarin Solid Dispersion in Rats with Acetaminophen-Induced Hepatotoxicity

We evaluated the bioavailability, liver distribution, and efficacy of silymarin-D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) solid dispersion (silymarin-SD) in rats with acetaminophen-induced hepatotoxicity (APAP) compared with silymarin alone. The solubility of silybin, the major and active component of silymarin, in the silymarin-SD group increased 23-fold compared with the silymarin group. The absorptive permeability of silybin increased by 4.6-fold and its efflux ratio decreased from 5.5 to 0.6 in the presence of TPGS. The results suggested that TPGS functioned as a solubilizing agent and permeation enhancer by inhibiting efflux pump. Thus, silybin concentrations in plasma and liver were increased in the silymarin-SD group and liver distribution increased 3.4-fold after repeated oral administration of silymarin-SD (20 mg/kg as silybin) for five consecutive days compared with that of silymarin alone (20 mg/kg as silybin). Based on higher liver silybin concentrations in the silymarin-SD group, the therapeutic effects of silymarin-SD in hepatotoxic rats were evaluated and compared with silymarin administration only. Elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were significantly decreased by silymarin-SD, silymarin, and TPGS treatments, but these decreases were much higher in silymarin-SD animals than in those treated with silymarin or TPGS. In conclusion, silymarin-SD (20 mg/kg as silybin, three times per day for 5 days) exhibited hepatoprotective properties toward hepatotoxic rats and these properties were superior to silymarin alone, which may be attributed to increased solubility, enhanced intestinal permeability, and increased liver distribution of the silymarin-SD formulation.

Anti-apoptotic effect of silymarin-loaded chitosan nanoparticles on hippocampal caspase-3 and Bcl-2 expression following cerebral ischemia/reperfusion injury

BACKGROUND

Cerebral ischemia/reperfusion (I/R) causes memory and learning impairments and apoptosis in the hippocampus. The aim of present study aimed to investigate the anti-apoptotic effects of silymarin-loaded chitosan nanoparticles (SM-CS-NPs) on the expression of Bcl-2 and Caspase-3 genes in hippocampal neurons after I/R injury.

MATERIAL AND METHODS

SM and SM-CS-NPs were orally administered (15 mg/kg) for 14 days, and then cerebral I/R injury was induced by the bilateral common carotid artery occlusion (BCCAO). One day after I/R induction, memory and learning impairments and various biochemical estimations were assessed.

RESULTS

Our results indicated that SM-CS-NPs improved I/R-induced memory and learning impairments and oxidative damage in the hippocampal region. The qRT-PCR analysis indicated that SM-CS-NPs pretreatment inhibited I/R-induced neuronal apoptosis by increasing the expression of Bcl-2 and decreasing the expression of Caspase-3 in the hippocampus.

CONCLUSION

These findings suggest that SM-CS-NPs exert neuroprotective effects, and the neuroprotection is likely to be associated with the regulation of Bcl-2 and Caspase-3, leading to inhibition of apoptotic cell death in hippocampal neurons.

Hepatoprotective activity of silymarin encapsulation against hepatic damage in albino rats

Liver fibrosis occurs due to liver injuries and toxins. Silymarin (SMR) extracted by the milk thistle seeds, is widely used such as herbal drug for its hepatoprotective properties. The purpose of this study to assess the properties of an optimized dose of encapsulated crude SMR on antidiabetic activity and liver fibrosis induced by paracetamol in male albino rat. Hepatic fibrosis was assessed by measuring liver enzymes. Results revealed that the consumption of encapsulated SMR, can effectively affluence the target and avoid the degradation of bioactive compound. Body weight of animal also significantly increased in each group during all the period. According to our optimized study, the long-term induction of SMR (300 mg/kg) significantly amplified survival time of rats with paracetamol induced hepatic injuries. The changes of liver fibrosis and the significant increase of hepatic enzyme biomarkers were also observed. In conclusion, the results suggest that SMR acts as a hepatoprotective agent by inhibiting the fibrogenisis and apoptosis in liver, as well as insulin resistance.

Therapeutic Applications of Solid Dispersions for Drugs and New Molecules: In Vitro and In Vivo Activities

This review aims to provide an overview of studies that address the use, in therapeutic applications, of solid dispersions (SDs) with biological activities in vitro and/or in vivo mainly made up of polymeric matrices, as well as to evaluate the bioactive activity of their constituents. This bibliographic survey shows that the development of solid dispersions provides benefits in the physicochemical properties of bioactive compounds, which lead to an increase in their biological potential. However, despite the reports found on solid dispersions, there is still a need for biological assay-based studies, mainly in vivo, to assist in the investigation and to devise new applications. Therefore, studies based on such an approach are of great importance to enhance and extend the use of solid dispersions in the most diverse therapeutic applications.

Formulation Strategies for Enhancing the Bioavailability of Silymarin: The State of the Art

Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, has anti-oxidant, anti-inflammatory, anti-cancer and anti-viral activities potentially useful in the treatment of several liver disorders, such as chronic liver diseases, cirrhosis and hepatocellular carcinoma. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 μg/mL), low bioavailability and poor intestinal absorption. To improve its bioavailability and provide a prolonged silymarin release at the site of absorption, the use of nanotechnological strategies appears to be a promising method to potentiate the therapeutic action and promote sustained release of the active herbal extract. The purpose of this study is to review the different nanostructured systems available in literature as delivery strategies to improve the absorption and bioavailability of silymarin.

Silymarin-laden PVP-PEG polymeric composite for enhanced aqueous solubility and dissolution rate: Preparation and in vitro characterization

The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone (PVP)-polyethylene glycol (PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000 (0.25/1.5/1.5, w/w/w) furnished the highest solubility (24.39±2.95 mg/mL) and an excellent dissolution profile (~100% in 40 min). The solubility enhancement with this formulation was ~1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.

Preparation, characterizations and anti-pollutant activity of 7,3',4'-trihydroxyisoflavone nanoparticles in particulate matter-induced HaCaT keratinocytes

Background

7,3',4'-Trihydroxyisoflavone (734THI), a secondary metabolite derived from daidzein in soybean, possesses several biological activities, including antioxidant, skin whitening and anti-atopic dermatitis properties, but the poor aqueous solubility of 734THI has limited its application in medicine and cosmetic industry.

Methods

The aim of the present study was to improve the physicochemical properties of 734THI using planetary ball mill preparation under a solvent-free process to improve its solubility and anti-pollutant activity.

Results

734THI nanoparticle powder (734THIN) was successfully prepared by the planetary ball mill technique using polyvinylpyrrolidone K30 as the excipient. 734THIN effectively increased the aqueous solubility and cellular uptake of 734THI by improving its physicochemical properties, including particle size reduction, crystalline-amorphous transformation and intermolecular hydrogen bonding with polyvinylpyrrolidone K30. In addition, 734THIN inhibited the overexpression of COX-2 and MMP-9 by downregulating MAPK pathway signaling in particulate matter-exposed HaCaT keratinocytes, while raw 734THI in PBS with low aqueous solubility did not show any anti-inflammatory or antiaging activity.

Conclusion

734THIN may be used as an additive in anti-pollutant skin care products for preventing particulate matter-induced inflammation and aging in skin.

Anti-Parkinson Potential of Silymarin: Mechanistic Insight and Therapeutic Standing

Parkinson’s disease (PD) involves aggregation of α-synuclein and progressive loss of dopaminergic neurons. Pathogenesis of PD may also be related to one’s genetic background. PD is most common among geriatric population and approximately 1–2% of population suffers over age 65 years. Currently no successful therapies are in practice for the management of PD and available therapies tend to decrease the symptoms of PD only. Furthermore, these are associated with diverse range of adverse effects profile. The neuroprotective effects of polyphenols are widely studied and documented. Among phytochemicals, silymarin is one of the most widely used flavonoids because of its extensive therapeutic properties and has been indicated in pathological conditions of prostate, CNS, lungs, skin, liver, and pancreas. Silymarin is a mixture of flavonolignans (silybin, isosilybin, and silychristin), small amount of flavonoids (taxifolin), fatty acids, and other polyphenolic compounds extracted from the dried fruit of Silybum marianum and is clinically used for hepatoprotective effects since ancient times. Neuroprotective effects of silymarin have been studied in various models of neurological disorders such as Alzheimer’s disease, PD, and cerebral ischemia. The aim of the present study is to provide a comprehensive review of the recent literature exploring the effects of silymarin administration on the progression of PD. Reducing oxidative stress, inflammatory cytokines, altering cellular apoptosis machinery, and estrogen receptor machinery are mechanisms that are responsible for neuroprotection by silymarin, as discussed in this review. Additionally, because of poor aqueous solubility, the bioavailability of silymarin is low and only 23–47% of silymarin reaches systemic circulation after oral administration. Our primary focus is on the chemical basis of the pharmacology of silymarin in the treatment of PD and its mechanisms and possible therapeutic/clinical status while addressing the bioavailability limitation.

Inhibitory Effect of Flavonolignans on the P2Y12 Pathway in Blood Platelets

Adenosine diphosphate (ADP) is the major platelet agonist, which is important in the shape changes, stability, and growth of the thrombus. Platelet activation by ADP is associated with the G protein-coupled receptors P2Y1 and P2Y12. The pharmacologic blockade of the P2Y12 receptor significantly reduces the risk of peripheral artery disease, myocardial infarction, ischemic stroke, and vascular death. Recent studies demonstrated the inhibition of ADP-induced blood platelet activation by three major compounds of the flavonolignans group: silybin, silychristin, and silydianin. For this reason, the aim of the current work was to verify the effects of silybin, silychristin, and silydianin on ADP-induced physiological platelets responses, as well as mechanisms of P2Y12-dependent intracellular signal transduction. We evaluated the effect of tested flavonolignans on ADP-induced blood platelets’ aggregation in platelet-rich plasma (PRP) (using light transmission aggregometry), adhesion to fibrinogen (using the static method), and the secretion of PF-4 (using the ELISA method). Additionally, using the double labeled flow cytometry method, we estimated platelet vasodilator-stimulated phosphoprotein (VASP) phosphorylation. We demonstrated a dose-dependent reduction of blood platelets’ ability to perform ADP-induced aggregation, adhere to fibrinogen, and secrete PF-4 in samples treated with flavonolignans. Additionally, we observed that all of the tested flavonolignans were able to increase VASP phosphorylation in blood platelets samples, which is correlated with P2Y12 receptor inhibition. All of these analyses show that silychristin and silybin have the strongest inhibitory effect on blood platelet activation by ADP, while silydianin also inhibits the ADP pathway, but to a lesser extent. The results obtained in this study clearly demonstrate that silybin, silychristin, and silydianin have inhibitory properties against the P2Y12 receptor and block ADP-induced blood platelet activation.

Evaluation of the Cytotoxicity and Genotoxicity of Flavonolignans in Different Cellular Models

Flavonolignans are the main components of silymarin, which represents 1.5-3% of the dry fruit weight of Milk thistle (Silybum marianum L. Gaernt.). In ancient Greece and Romania, physicians and herbalists used the Silybum marianum to treat a range of liver diseases. Besides their hepatoprotective action, silymarin flavonolignans have many other healthy properties, such as anti-platelet and anti-inflammatory actions. The aim of this study was to evaluate the toxic effect of flavonolignans on blood platelets, peripheral blood mononuclear cells (PBMCs) and human lung cancer cell line-A549-using different molecular techniques. We established that three major flavonolignans: silybin, silychristin and silydianin, in concentrations of up to 100 µM, have neither a cytotoxic nor genotoxic effect on blood platelets, PMBCs and A549. We also saw that silybin and silychristin have a protective effect on cellular mitochondria, observed as a reduction of spontaneous mitochondrial DNA (mtDNA) damage in A549, measured as mtDNA copies, and mtDNA lesions in ND1 and ND5 genes. Additionally, we observed that flavonolignans increase the blood platelets' mitochondrial membrane potential and reduce the generation of reactive oxygen species in blood platelets. Our current findings show for the first time that the three major flavonolignans, silybin, silychristin and silydianin, do not have any cytotoxicity and genotoxicity in various cellular models, and that they actually protect cellular mitochondria. This proves that the antiplatelet and anti-inflammatory effect of these compounds is part of our molecular health mechanisms.

Silybin, a Major Bioactive Component of Milk Thistle (Silybum marianum L. Gaernt.)-Chemistry, Bioavailability, and Metabolism

Milk thistle (Silybum marianum) is a medicinal plant that has been used for thousands of years as a remedy for a variety of ailments. The main component of S. marianum fruit extract (silymarin) is a flavonolignan called silybin, which is not only the major silymarin element but is also the most active ingredient of this extract, which has been confirmed in various studies. This compound belongs to the flavonoid group known as flavonolignans. Silybin's structure consists in two main units. The first is based on a taxifolin, the second a phenyllpropanoid unit, which in this case is conyferil alcohol. These two units are linked together into one structure by an oxeran ring. Since the 1970s, silybin has been regarded in official medicine as a substance with hepatoprotective properties. There is a large body of research that demonstrates silybin's many other healthy properties, but there are still a lack of papers focused on its molecular structure, chemistry, metabolism, and novel form of administration. Therefore, the aim of this paper is a literature review presenting and systematizing our knowledge of the silybin molecule, with particular emphasis on its structure, chemistry, bioavailability, and metabolism.

Effect of HM30181 mesylate salt-loaded microcapsules on the oral absorption of paclitaxel as a novel P-glycoprotein inhibitor

The purpose of this study was to develop HM30181 mesylate salt (HM30181M)-loaded microcapsules as a novel P-glycoprotein inhibitor for enhancing the oral absorption of paclitaxel. The effect of various carriers including hydrophilic polymers and solvents on the solubility of HM30181M were evaluated. Among the hydrophilic polymers and solvents tested, HPMC and methylene chloride (and ethanol) provided the highest HM30181M solubility. Numerous HM30181M-loaded microcapsules were prepared with HPMC, silicon dioxide and acidifying agents using a spray-drying technique, and their solubility, dissolution and physicochemical properties were evaluated. Furthermore, a pharmacokinetic study was performed after oral administration of paclitaxel alone, simultaneously with HM30181M powder or HM30181M-loaded microcapsules to rats. Among the acidifying agents investigated, phosphoric acid provided the best improvement in the solubility and dissolution of HM30181M. Moreover, the microcapsule composed of HM30181M, HPMC, silicon dioxide and phosphoric acid at a weight ratio of 3:6:3:2 remarkably enhanced the solubility and dissolution of HM30181M compared with the HM30181M powder alone. The microcapsules were spherical in shape, had a reduced particle size of about 7μm, and contained HM30181M in an amorphous state. Furthermore, this microcapsule significantly enhanced HM30181M absorption, making it about 1.7-fold faster and 1.6-fold greater after simultaneous administration, leading to about 70- and 2-fold improved oral bioavailability of paclitaxel compared with paclitaxel alone and the simultaneous administration with HM30181M powder, respectively. Thus, this novel microcapsule could be a potential candidate for effective P-glycoprotein inhibition during oral administration of paclitaxel.

Enhanced oral bioavailability of silymarin using liposomes containing a bile salt: preparation by supercritical fluid technology and evaluation in vitro and in vivo

The aim of this investigation was to develop a procedure to improve the dissolution and bioavailability of silymarin (SM) by using bile salt-containing liposomes that were prepared by supercritical fluid technology (ie, solution-enhanced dispersion by supercritical fluids [SEDS]). The process for the preparation of SM-loaded liposomes containing a bile salt (SM-Lip-SEDS) was optimized using a central composite design of response surface methodology with the ratio of SM to phospholipids (w/w), flow rate of solution (mL/min), and pressure (MPa) as independent variables. Particle size, entrapment efficiency (EE), and drug loading (DL) were dependent variables for optimization of the process and formulation variables. The particle size, zeta potential, EE, and DL of the optimized SM-Lip-SEDS were 160.5 nm, −62.3 mV, 91.4%, and 4.73%, respectively. Two other methods to produce SM liposomes were compared to the SEDS method. The liposomes obtained by the SEDS method exhibited the highest EE and DL, smallest particle size, and best stability compared to liposomes produced by the thin-film dispersion and reversed-phase evaporation methods. Compared to the SM powder, SM-Lip-SEDS showed increased in vitro drug release. The in vivo AUC_0−t of SM-Lip-SEDS was 4.8-fold higher than that of the SM powder. These results illustrate that liposomes containing a bile salt can be used to enhance the oral bioavailability of SM and that supercritical fluid technology is suitable for the preparation of liposomes.

Nano-silymarin provides protection against γ-radiation-induced oxidative stress in cultured human embryonic kidney cells

Radiation can produce biological damage, mainly oxidative stress, via production of free radicals, including reactive oxygen species (ROS). Nanoparticles are of interest as radioprotective agents, particularly due to their high solubility and bioavailability. Silymarin is a hepatoprotective agent but has poor oral bioavailability. Silymarin was formulated as a nanoemulsion with the aim of improving its bioavailability and therapeutic efficacy. In the present study, we evaluated self-nanoemulsifying drug delivery systems (SNEDDS) formulated with surfactants and co-surfactants. Nano-silymarin was characterized by estimating % transmittance, globule size, and polydispersity index, and by transmission electron microscopy (TEM). The nano-silymarin obtained was in the range of 3-8nm diameter. With regard to DNA damage, measured by a plasmid relaxation assay, maximum protection was obtained at 10μg/mL. Cytotoxicity of nano-silymarin to human embryonic kidney (HEK) cells was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Protective efficacy against γ-radiation was assessed by reduction in micronucleus frequency and ROS generation, using the 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay. Radiation-induced apoptosis was estimated by microscopic analysis and cell-cycle estimation. Nano-silymarin was radioprotective, supporting the possibility of developing new approaches to radiation protection via nanotechnology.

Formulation development and systematic optimization of stabilized ziprasidone hydrochloride capsules devoid of any food effect

CONTEXT AND OBJECTIVE

The objective of the study was to develop a stable capsule formulation of ziprasidone hydrochloride which can be administered without regards to food intake.

MATERIALS AND METHODS

The unstable anhydrous form of ziprasidone hydrochloride was stabilized employing hot-melt extrusion and further optimized by 3² central composite design. The formulation was optimized after establishing acceptable ranges for response variables like disintegration time, dissolution and impurity profile. A crossover fasted and fed in vivo study was conducted in human volunteers to assess the food-effect of optimized formulation vis-à-vis the marketed brand.

RESULTS AND DISCUSSION

The optimized formulation met in-house specifications for various response variables. Further, high values of correlation coefficient vouch the adequate selection of experimental design and its high prognostic ability. In our study, no significant difference was observed between the C_max and AUC values after administration of the optimized formulation in fasted and fed states. On the contrary, there was a statistically significant increase in the C_max and AUC values after oral administration of Zeldox in fed state in comparison to fasted state.

CONCLUSIONS

The present study describes the successful development of a stable formulation of 20 mg of ziprasidone devoid of any food-effects.