Enhanced oral bioavailability of silybin by a supersaturatable self-emulsifying drug delivery system (S-SEDDS)

Development, Optimization, and in vitro Evaluation of Silybin-loaded PLGA Nanoparticles and Decoration with 5TR1 Aptamer for Targeted Delivery to Colorectal Cancer Cells

Chemotherapeutic agents often lack specificity, intratumoral accumulation, and face drug resistance. Targeted drug delivery systems based on nanoparticles (NPs) mitigate these issues. Poly (lactic-co-glycolic acid) (PLGA) is a well-studied polymer, commonly modified with aptamers (Apts) for cancer diagnosis and therapy. In this study, silybin (SBN), a natural agent with established anticancer properties, was encapsulated into PLGA NPs to control delivery and improve its poor solubility. The field-emission scanning electron microscopy (FE-SEM) showed spherical and uniform morphology of optimum SBN-PLGA NPs with 138.57±1.30nm diameter, 0.202±0.004 polydispersity index (PDI), -16.93±0.45mV zeta potential (ZP), and 70.19±1.63% entrapment efficiency (EE). The results of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) showed no chemical interaction between formulation components, and differential scanning calorimetry (DSC) thermograms confirmed efficient SBN entrapment in the carrier. Then, the optimum formulation was functionalized with 5TR1 Apt for active targeted delivery of SBN to colorectal cancer (CRC) cells in vitro. The SBN-PLGA-5TR1 nanocomplex released SBN at a sustained and constant rate (zero-order kinetic), favoring passive delivery to acidic CRC environments. The MTT assay demonstrated the highest cytotoxicity of the SBN-PLGA-5TR1 nanocomplex in C26 and HT29 cells and no significant cytotoxicity in normal cells. Apoptosis analysis supported these results, showing early apoptosis induction with SBN-PLGA-5TR1 nanocomplex which indicated this agent could cause programmed death more than necrosis. This study presents the first targeted delivery of SBN to cancer cells using Apts. The SBN-PLGA-5TR1 nanocomplex effectively targeted and suppressed CRC cell proliferation, providing valuable insights into CRC treatment without harmful effects on healthy tissues.

Current Application of Nanoparticle Drug Delivery Systems to the Treatment of Anaplastic Thyroid Carcinomas

Anaplastic thyroid carcinomas (ATCs) are a rare subtype of thyroid cancers with a low incidence but extremely high invasiveness and fatality. The treatment of ATCs is very challenging, and currently, a comprehensive individualized therapeutic strategy involving surgery, radiotherapy (RT), chemotherapy, BRAF/MEK inhibitors (BRAFi/MEKi) and immunotherapy is preferred. For ATC patients in stage IVA/IVB, a surgery-based comprehensive strategy may provide survival benefits. Unfortunately, ATC patients in IVC stage barely get benefits from the current treatment. Recently, nanoparticle delivery of siRNAs, targeted drugs, cytotoxic drugs, photosensitizers and other agents is considered as a promising anti-cancer treatment. Nanoparticle drug delivery systems have been mainly explored in the treatment of differentiated thyroid cancer (DTC). With the rapid development of drug delivery techniques and nanomaterials, using hybrid nanoparticles as the drug carrier to deliver siRNAs, targeted drugs, immune drugs, chemotherapy drugs and phototherapy drugs to ATC patients have become a hot research field. This review aims to describe latest findings of nanoparticle drug delivery systems in the treatment of ATCs, thus providing references for the further analyses.

Lipid based formulations as supersaturating oral delivery systems: From current to future industrial applications

Lipid-based formulations, in particular supersaturated lipid-based formulations, are important delivery approaches when formulating challenging compounds, as especially low water-soluble compounds profit from delivery in a pre-dissolved state. In this article, the classification of lipid-based formulation is described, followed by a detailed discussion of different supersaturated lipid-based formulations and the recent advances reported in the literature. The supersaturated lipid-based formulations discussed include both the in situ forming supersaturated systems as well as the thermally induced supersaturated lipid-based formulations. The in situ forming drug supersaturation by lipid-based formulations has been widely employed and numerous clinically available products are on the market. There are some scientific gaps in the field, but in general there is a good understanding of the mechanisms driving the success of these systems. For thermally induced supersaturation, the technology is not yet fully understood and developed, hence more research is required in this field to explore the formulations beyond preclinical studies and initial clinical trials.

Integrating Artificial Intelligence with Quality by Design in the Formulation of Lecithin/Chitosan Nanoparticles of a Poorly Water-Soluble Drug

The aim of the current study is to explore the potential of artificial intelligence (AI) when integrated with Quality by Design (QbD) approach in the formulation of a poorly water-soluble drug, for its potential use in carcinoma. Silymarin is used as a model drug for its potential effectiveness in liver cancer. A detailed QbD approach was applied. The effect of the critical process parameters was studied on each of the particle size, size distribution, and entrapment efficiency. Response surface designs were applied in the screening and optimization of lecithin/chitosan nanoparticles, to obtain an optimized formula. The release rate was tested, where artificial neural network models were used to predict the % release of the drug from the optimized formula at different time intervals. The optimized formula was tested for its cytotoxicity. A design space was established, with an optimized formula having a molar ratio of 18.33:1 lecithin:chitosan and 38.35 mg silymarin. This resulted in nanoparticles with a size of 161 nm, a polydispersity index of 0.2, and an entrapment efficiency of 97%. The optimized formula showed a zeta potential of +38 mV, with well-developed spherical particles. AI successfully showed high prediction ability of the drug's release rate. The optimized formula showed an enhancement in the cytotoxic effect of silymarin with a decreased IC50 compared to standard silymarin. Lecithin/chitosan nanoparticles were successfully formulated, with deep process and product understanding. Several tools were used as AI which could shift pharmaceutical formulations from experience-dependent studies to data-driven methodologies in the future.

Lipid-Based Delivery Systems for Flavonoids and Flavonolignans: Liposomes, Nanoemulsions, and Solid Lipid Nanoparticles

Herbal chemicals with a long history in medicine have attracted a lot of attention. Flavonolignans and flavonoids are considered as two classes of the above-mentioned compounds with different functional groups which exhibit several therapeutic capabilities such as antimicrobial, anti-inflammatory, antioxidant, antidiabetic, and anticancer activities. Based on the studies, high hydrophobic properties of the aforementioned compounds limit their bioavailability inside the human body and restrict their wide application. Nanoscale formulations such as solid lipid nanoparticles, liposomes, and other types of lipid-based delivery systems have been introduced to overcome the above-mentioned challenges. This approach allows the aforementioned hydrophobic therapeutic compounds to be encapsulated between hydrophobic structures, resulting in improving their bioavailability. The above-mentioned enhanced delivery system improves delivery to the targeted sites and reduces the daily required dosage. Lowering the required daily dose improves the performance of the drug by diminishing its side effects on non-targeted tissues. The present study aims to highlight the recent improvements in implementing lipid-based nanocarriers to deliver flavonolignans and flavonoids.

Solvent Free Twin Screw Processed Silybin Nanophytophospholipid: In Silico, In Vitro and In Vivo Insights

Silybin (SIL) is a polyphenolic phytoconstituent that is commonly used to treat liver disorders. It is difficult to fabricate an orally delivered SIL product due to its low oral bioavailability (0.95%). Therefore, the current research focusses on the development of a novel composition of a phospholipid complex, termed as nanophytophospholipid, of SIL by employing a unique, solvent-free Twin Screw Process (TSP), with the goal of augmenting the solubility and bioavailability of SIL. The optimised SIL-nanophytophospholipid (H6-SNP) was subjected to physicochemical interactions by spectrometry, thermal, X-ray and electron microscopy. The mechanism of drug and phospholipid interaction was confirmed by molecular docking and dynamics studies. Saturation solubility, in vitro dissolution, ex vivo permeation and preclinical pharmacokinetic studies were also conducted. H6-SNP showed good complexation efficiency, with a high practical yield (80%). The low particle size (334.7 ± 3.0 nm) and positively charged zeta potential (30.21 ± 0.3 mV) indicated the immediate dispersive nature of H6-SNP into nanometric dimensions, with good physical stability. Further high solubility and high drug release from the H6-SNP was also observed. The superiority of the H6-SNP was demonstrated in the ex vivo and preclinical pharmacokinetic studies, displaying enhanced apparent permeability (2.45-fold) and enhanced bioavailability (1.28-fold). Overall, these findings indicate that not only can phospholipid complexes be formed using solvent-free TSP, but also that nanophytophospholipids can be formed by using a specific quantity of lipid, drug, surfactant, superdisintegrant and diluent. This amalgamation of technology and unique composition can improve the oral bioavailability of poorly soluble and permeable phytoconstituents or drugs.

Tadalafil-Loaded Self-Nanoemulsifying Chewable Tablets for Improved Bioavailability: Design, In Vitro, and In Vivo Testing

This research aimed to develop innovative self-nanoemulsifying chewable tablets (SNECT) to increase oral bioavailability of tadalafil (TDL), a nearly insoluble phosphodiesterase-5 inhibitor. Cinnamon essential oil, PEG 40 hydrogenated castor oil (Cremophor® RH 40), and polyethylene glycol 400 served as the oil, surfactant, and cosurfactant in the nanoemulsifying system, respectively. Primary liquid self-nanoemulsifying delivery systems (L-SNEDDS) were designed using phase diagrams and tested for dispersibility, droplet size, self-emulsifying capability, and thermodynamic stability. Adsorption on a carrier mix of silicon dioxide and microcrystalline cellulose was exploited to solidify the optimum L-SNEDDS formulation as self-nanoemulsifying granules (SNEG). Lack of crystalline TDL within the granules was verified by DSC and XRPD. SNEG were able to create a nanoemulsion instantaneously (165 nm), a little larger than the original nanoemulsion (159 nm). SNECT were fabricated by compressing SNEG with appropriate excipients. The obtained SNECT retained their quick dispersibility dissolving 84% of TDL within 30 min compared to only 18% dissolution from tablets of unprocessed TDL. A pharmacokinetic study in Sprague−Dawley rats showed a significant increase in Cmax (2.3-fold) and AUC0−24 h (5.33-fold) of SNECT relative to the unprocessed TDL-tablet (p < 0.05). The stability of TDL-SNECT was checked against dilutions with simulated GI fluids. In addition, accelerated stability tests were performed for three months at 40 ± 2 °C and 75% relative humidity. Results revealed the absence of obvious changes in size, PDI, or other tablet parameters before and after testing. In conclusion, current findings illustrated effectiveness of SNECT to enhance TDL dissolution and bioavailability in addition to facilitating dose administration.

A Comprehensive Insight on Self Emulsifying Drug Delivery Systems

BACKGROUND

The oral route is a highly recommended route for the delivery of a drug. But most lipophilic drugs are difficult to deliver via this route due to their low aqueous solubility. Selfemulsifying drug delivery systems (SEDDS) have emerged as a potential approach of increasing dissolution of a hydrophobic drug due to spontaneous dispersion in micron or nano sized globules in the GI tract under mild agitation.

OBJECTIVE

The main motive of this review article is to describe the mechanisms, advantages, disadvantages, factors affecting, effects of excipients, possible mechanisms of enhancing bioavailability, and evaluation of self-emulsifying drug delivery systems.

RESULTS

Self emulsifying systems incorporate the hydrophobic drug inside the oil globules, and a monolayer is formed by surfactants to provide the low interfacial tension, which leads to improvement in the dissolution rate of hydrophobic drugs. The globule size of self-emulsifying systems depends upon the type and ratio of excipients in which they are used. The ternary phase diagram is constructed to find out the range of concentration of excipients used. This review article also presents recent and updated patents on self-emulsifying drug delivery systems. Self-emulsifying systems have the ability to enhance the oral bioavailability and solubility of lipophilic drugs.

CONCLUSION

This technique offers further advantages such as bypassing the first pass metabolism via absorption of drugs through the lymphatic system, easy manufacturing, reducing enzymatic hydrolysis, inter and intra subject variability, and food effects.

Supersaturation-Based Drug Delivery Systems: Strategy for Bioavailability Enhancement of Poorly Water-Soluble Drugs

At present, the majority of APIs synthesized today remain challenging tasks for formulation development. Many technologies are being utilized or explored for enhancing solubility, such as chemical modification, novel drug delivery systems (microemulsions, nanoparticles, liposomes, etc.), salt formation, and many more. One promising avenue attaining attention presently is supersaturated drug delivery systems. When exposed to gastrointestinal fluids, drug concentration exceeds equilibrium solubility and a supersaturation state is maintained long enough to be absorbed, enhancing bioavailability. In this review, the latest developments in supersaturated drug delivery systems are addressed in depth.

Solidification of Self-Emulsifying Drug Delivery Systems as a Novel Approach to the Management of Uncomplicated Malaria

Malaria affects millions of people annually, especially in third-world countries. The mainstay of treatment is oral anti-malarial drugs and vaccination. An increase in resistant strains of malaria parasites to most of the current anti-malarial drugs adds to the global burden. Moreover, existing and new anti-malarial drugs are hampered by significantly poor aqueous solubility and low permeability, resulting in low oral bioavailability and patient noncompliance. Lipid formulations are commonly used to increase solubility and efficacy and decrease toxicity. The present review discusses the findings from studies focusing on specialised oral lipophilic drug delivery systems, including self-emulsifying drug delivery systems (SEDDSs). SEDDSs facilitate the spontaneous formation of liquid emulsions that effectively solubilise the incorporated drugs into the gastrointestinal tract and thereby improve the absorption of poorly-soluble anti-malaria drugs. However, traditional SEDDSs are normally in liquid dosage forms, which are delivered orally to the site of absorption, and are hampered by poor stability. This paper discusses novel solidification techniques that can easily and economically be up-scaled due to already existing industrial equipment that could be utilised. This method could, furthermore, improve product stability and patient compliance. The possible impact that solid oral SEDDSs can play in the fight against malaria is highlighted.

Development of Piperine-Loaded Solid Self-Nanoemulsifying Drug Delivery System: Optimization, In-Vitro, Ex-Vivo, and In-Vivo Evaluation

Hypertension is a cardiovascular disease that needs long-term medication. Oral delivery is the most common route for the administration of drugs. The present research is to develop piperine self-nanoemulsifying drug delivery system (PE-SNEDDS) using glyceryl monolinoleate (GML), poloxamer 188, and transcutol HP as oil, surfactant, and co-surfactant, respectively. The formulation was optimized by three-factor, three-level Box-Behnken design. PE-SNEDDs were characterized for globule size, emulsification time, stability, in-vitro release, and ex-vivo intestinal permeation study. The optimized PE-SNEDDS (OF3) showed the globule size of 70.34 ± 3.27 nm, percentage transmittance of 99.02 ± 2.02%, and emulsification time of 53 ± 2 s Finally, the formulation OF3 was transformed into solid PE-SNEDDS (S-PE-SNEDDS) using avicel PH-101 as adsorbent. The reconstituted SOF3 showed a globule size of 73.56 ± 3.54 nm, PDI of 0.35 ± 0.03, and zeta potential of −28.12 ± 2.54 mV. SEM image exhibited the PE-SNEDDS completely adsorbed on avicel. Thermal analysis showed the drug was solubilized in oil, surfactant, and co-surfactant. S-PE-SNEDDS formulation showed a more significant (p < 0.05) release (97.87 ± 4.89% in 1 h) than pure PE (27.87 ± 2.65% in 1 h). It also exhibited better antimicrobial activity against S. aureus and P. aeruginosa and antioxidant activity as compared to PE dispersion. The in vivo activity in rats exhibited better (p < 0.05) antihypertensive activity as well as 4.92-fold higher relative bioavailability than pure PE dispersion. Finally, from the results it can be concluded that S-PE-SNEDDS might be a better approach for the oral delivery to improve the absorption and therapeutic activity.

The Emerging Role of Nanomedicine in the Management of Nonalcoholic Fatty Liver Disease: A State-of-the-Art Review

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease that can lead to end-stage liver disease needing a liver transplant. Many pharmacological approaches are used to reduce the disease progression in NAFLD. However, current strategies remain ineffective to reverse the progression of NAFLD completely. Employing nanoparticles as a drug delivery system has demonstrated significant potential for improving the bioavailability of drugs in the treatment of NAFLD. Various types of nanoparticles are exploited in this regard for the management of NAFLD. In this review, we cover the current therapeutic approaches to manage NAFLD and provide a review of recent up-to-date advances in the uses of nanoparticles for the treatment of NAFLD.

Supersaturated LFCS type III self-emulsifying delivery systems of sorafenib tosylate with improved biopharmaceutical performance: QbD-enabled development and evaluation

The current studies investigate the application of quality by design-enabled type III self-emulsifying delivery system (Type III-SEDDS) of sorafenib tosylate (SFN) in improving its biopharmaceutical attributes. Initially, lipidic and emulsifying excipients were selected by carrying out solubility and phase titration experiments. After screening studies using Taguchi OA design, Type III-SEDDS were further optimised using D-optimal mixture design. The prepared formulations were assessed for globule size, zeta potential and percent of drug release. Following graphical optimisation, the optimum formulation was earmarked and further supersaturated to form saturated Type III-SEDDS (Sat-Type III-SEDDS) using a combination of HPMC and PVP to improve the stability of the formulation for a prolonged period. In vitro drug release of Type III-SEDDS study indicated approximately 8-fold improvement in dissolution rate over the pure powder drug. Cell uptake studies demonstrated higher uptake of dye-loaded Type III-SEDDS formulations in Caco-2 cells vis-à-vis plain dye. Cytotoxicity assay on Hep G2 cells revealed significant reduction in cell growth with Type III- and Sat-Type III-SEDDS vis-à-vis the pure drug. Furthermore, in situ permeation studies carried out using Wistar rats exhibited nearly 8.3- to 10.2-fold augmentation in permeation and absorption parameters of the drug from the Type III- and Sat-Type III-SEDDS, respectively, vis-à-vis the pure drug. Pharmacokinetic studies indicated nearly 3.98- and 3.62-fold improvement in AUC_0-72, and 8.01- and 5.42-fold in C_max, along with 0.25-fold decrease in T_max of the drug from Type III- and Sat-Type III-SEDDS, respectively, in comparison with the SFN suspension. Furthermore, high degree of level A linear correlation was established between fractions of drug dissolved (in vitro) and of drug absorbed (in vivo) at the corresponding time points for Sat-Type III-SEDDS and pure drug, whereas the Type III-SEDDS exhibited a nonlinear relationship. Stability studies indicated the robustness of Sat-Type III-SEDDS, when stored at 25 °C for 3 months. Overall, the manuscript documents the successful systematic development of SFN-loaded Sat-Type III-SEDDS with distinctly improved biopharmaceutical performance. Graphical abstract.

Preparation and evaluation of oral self-microemulsifying drug delivery system of Chlorophyll

OBJECTIVE

This study was aimed at improving the water solubility and oral bioavailability of Chl by self-microemulsifying drug delivery system (Chl-SMEDDS).

METHODS

Compatibility experiments, pseudo-ternary phase diagram and central composite design were used to optimize the formulation. The selected systems were further evaluated for physical characteristics, including particle size, zeta potential, and appearance. The stability, in vitro dispersion test, and in vivo intestinal perfusion experiments were used to evaluate the SMEDDS.

RESULTS

The optimal composition of Chl-SMEDDS included: Labrafil M 1944 CS (35%), kolliphor RH 40 (46%), Transcutol HP (19%) and 60 mg/g Chl. The appearance of water emulsified Chl-SMEDDS was green and transparent. The particle size, ζ-potential, and transmission electron microscopy studies showed that spherical globules of Chl-SMEDDS with a size of about 22.82 ± 1.29 nm and a negative surface charge of -24.21 ± 3.45 mV were obtained. Chl-SMEDDS could remain stable at 25 °C and 4 °C for at least 6 months. The dispersion test showed that Chl-SMEDDS dispersed spontaneously to form microemulsion after disintegration of capsule shell and 90% drug dispersed in just 30 min in pH 1.2 HCl without any drug precipitation during the test period. In vivo intestinal perfusion experiment revealed that the main absorption site for Chl-SMEDDS was duodenum.

CONCLUSIONS

This study indicates that SMEDDS formulation could be an effective strategy for the oral administration of Chl.

Abdulbaqi I, Seok Ming T, Siok Yee C, A. Wahab H, Asif SM, Darwis Y. Liquid and Solid Self-Emulsifying Drug Delivery Systems (SEDDs) as Carriers for the Oral Delivery of Azithromycin: Optimization, In Vitro Characterization and Stability Assessment

Azithromycin (AZM) is a macrolide antibiotic used for the treatment of various bacterial infections. The drug is known to have low oral bioavailability (37%) which may be attributed to its relatively high molecular weight, low solubility, dissolution rate, and incomplete intestinal absorption. To overcome these drawbacks, liquid (L) and solid (S) self-emulsifying drug delivery systems (SEDDs) of AZM were developed and optimized. Eight different pseudo-ternary diagrams were constructed based on the drug solubility and the emulsification studies in various SEDDs excipients at different surfactant to co-surfactant (Smix) ratios. Droplet size (DS) < 150 nm, dispersity (Đ) ≤ 0.7, and transmittance (T)% > 85 in three diluents of distilled water (DW), 0.1 mM HCl, and simulated intestinal fluids (SIF) were considered as the selection criteria. The final formulations of L-SEDDs (L-F1(H)), and S-SEDDs (S-F1(H)) were able to meet the selection requirements. Both formulations were proven to be cytocompatible and able to open up the cellular epithelial tight junctions (TJ). The drug dissolution studies showed that after 5 min > 90% and 52.22% of the AZM was released from liquid and solid SEDDs formulations in DW, respectively, compared to 11.27% of the pure AZM, suggesting the developed SEDDs may enhance the oral delivery of the drug. The formulations were stable at refrigerator storage conditions.

Enhanced oral bioavailability of Bisdemethoxycurcumin-loaded self-microemulsifying drug delivery system: Formulation design, in vitro and in vivo evaluation

In this study, we sought to overcome the poor solubility and bioavailability of bismethoxycurcumin (BDMC) by fabricating a BDMC-loaded self micro-emulsifying system (BDMC-SMEDDS). Solubility and compatibility tests, pseudo-ternary phase diagrams (PTPDs) as well as d-optimal concept was applied to design the formulation. The assessment of the prepared BDMC-SMEDDS in-vitro mainly included droplet size (DS) and entrapment efficiency (EE) determination, morphology, drug release and stability testing. Besides, the in vivo behavior was also evaluated after oral administration of BDMC-SMEDDS to rats. The optimal formulation was found to compose of Kolliphor EL (K-EL, emulsifier, 645.3 mg), PEG 400 (co-emulsifier, 147.2 mg), ethyl oleate (EO, oil, 207.5 mg) and BDMC (50 mg). The BDMC-SMEDDS with satisfactory stability had a mean size of 21.25 ± 3.23 nm and EE of 98.31 ± 0.32%. Roughly 70% of BDMC was released from BDMC-SMEDDS within 84 h compared with <20% from the free BDMC. More importantly, the in-vivo behavior of BDMC-SMEDDS showed that the AUC_(0-12h) and plasma concentration of BDMC increased substantially as compared to the free BDMC. Altogether, BDMC-SMEDDS has the potential to enhance the solubility and bioavailability of BDMC and could be applied in the clinics.

Amelioration of lipophilic compounds in regards to bioavailability as self-emulsifying drug delivery system (SEDDS)

Background

High lipophilicity and poor aqueous solubility are the endemic problems of new drug molecules. Sixty to seventy percent of these drugs are unable to solubilize completely in aqueous media, or have very low permeability. This hampers their oral absorption and further leads to their poor bioavailability. Various researches are in progress to overcome these limitations. Novel technologies like nano-carrier systems have become popular for improving the solubility of drugs.

Main body

Lipid-based formulations, among nano systems, are taking pace for the enhancement of solubility, oral absorption, and hence the bioavailability of drugs. Among the lipid formulations, self-emulsification systems are gaining popularity by offering various advantages to delivery systems. Self-emulsifying drug delivery systems (SEDDS) are isotropic blends of oil and surfactant/co-surfactants. These ingredients upon gentle agitation in aqueous media results in the formation of o/w emulsion. In spite of many works published in SEDDS, the major concerns of this article are to discuss the various approaches to formulate a good lipid-based carrier system for poorly aqueous soluble drugs, role of various polymers, and their categories used in the formulation along-with the modern technologies used for enhancing the stability of liquid SEDDS. This review majorly focuses upon the problems related to the poor aqueous solubility of the newer lipid molecules and the solutions to overcome their solubility and in addition bioavailability.

Conclusion

As per the researches done in formulation and optimization of SEDDS for the enhancement of bioavailability of lipophilic molecules, it can be stated that the aqueous solubility as well as bioavailability can be increased by many folds compared to their marketed or other oral formulations.

Current Status of Supersaturable Self-Emulsifying Drug Delivery Systems

Self-emulsifying drug delivery systems (SEDDSs) are a vital strategy to enhance the bioavailability (BA) of formulations of poorly water-soluble compounds. However, these formulations have certain limitations, including in vivo drug precipitation, poor in vitro in vivo correlation due to a lack of predictive in vitro tests, issues in handling of liquid formulation, and physico-chemical instability of drug and/or vehicle components. To overcome these limitations, which restrict the potential usage of such systems, the supersaturable SEDDSs (su-SEDDSs) have gained attention based on the fact that the inclusion of precipitation inhibitors (PIs) within SEDDSs helps maintain drug supersaturation after dispersion and digestion in the gastrointestinal tract. This improves the BA of drugs and reduces the variability of exposure. In addition, the formulation of solid su-SEDDSs has helped to overcome disadvantages of liquid or capsule dosage form. This review article discusses, in detail, the current status of su-SEDDSs that overcome the limitations of conventional SEDDSs. It discusses the definition and range of su-SEDDSs, the principle mechanisms underlying precipitation inhibition and enhanced in vivo absorption, drug application cases, biorelevance in vitro digestion models, and the development of liquid su-SEDDSs to solid dosage forms. This review also describes the effects of various physiological factors and the potential interactions between PIs and lipid, lipase or lipid digested products on the in vivo performance of su-SEDDSs. In particular, several considerations relating to the properties of PIs are discussed from various perspectives.

Application of Box–Behnken design and desirability function in the development and optimization of self-nanoemulsifying drug delivery system for enhanced dissolution of ezetimibe

Background

This study is focused on developing and optimizing a self-nanoemulsifying drug delivery system (SNEDDS) of BCS class II drug (ezetimibe) through Box–Behnken design (BBD) and desirability function for enhanced dissolution.

Pseudoternary phase diagrams were created by taking oil (Peceol), surfactant (Tween80), and co-surfactant (Transcutol-P) and the concentration ranges were identified for generating BBD. The composition of ezetimibe-SNEDDS was optimized through various response variables viz. globule size (Y1), %transmittance (Y2), self-emulsification time (Y3), dissolution after 5 min and 40 min (Y4, Y5). Optimized formulation was characterized for various physicochemical properties.

Results

Pseudoternary phase diagram having maximum nano-emulsification area was selected to formulate SNEDDS. Derived polynomial equation and model graphs were exercised to investigate the impact of formulation variables on the responses. Significant effect of formulation composition on the responses was observed (p < 0.05). The formulation with least oil (10%) and high surfactant (60%) exhibited low globule size (24.4 ± 2.07 nm), low emulsification time (55 s) but high %transmittance (101.2%) and drug release (49.21% after 5 min; 95.27% after 40 min). Based on the desirability function, the optimized formulation was selected and reformulated. The optimized formulation (FF1) was found to be uniform, stable, and showed similar observed and predicted responses.

Conclusion

The potential of SNEDDS in improving the dissolution profile of weakly soluble drug and the applicability of BBD with desirability function in optimizing a SNEDD formulation has made it possible to identify the impact of various independent variables on optimization of the formulation for better responses.

Self microemulsifying drug delivery system of lurasidone hydrochloride for enhanced oral bioavailability by lymphatic targeting: In vitro, Caco-2 cell line and in vivo evaluation

The global aim of this research was to develop and evaluate self-microemulsifying drug delivery system (SMEDDS) to improve oral bioavailability of Lurasidone Hydrochloride (LH). A chylomicron flow blocking approach was used to evaluate lymphatic drug transport. The developed LH-SMEDDS was composed of Capmul MCM C8 (oil), Cremophor EL (surfactant) and Transcutol HP (co-surfactant). Highest microemulsifying area was obtained at 3:1 ratio (surfactant:cosurfactant) and mean globule size was found to be 49.22 ± 1.60 nm. More than 98% drug release was obtained with LH-SMEDDS in phosphate buffer pH 6.8. Confocal microscopy and flow cytometry studies revealed higher fluorescence indicating deeper penetration across Caco-2 cells with Coumarin-6 SMEDDS as compared to Coumarin-6 solution. Mean Fluorescence Intensity (MFI) with Coumarin-6 loaded SMEDDS was increased 25.57 times with respect to Coumarin-6 solution. The permeability across Caco-2 cells was enhanced 3 times with LH-SMEDDS as compared to LH-suspension. Furthermore, Area Under Curve with LH-SMEDDS was found to be 2.92 times higher than that of LH suspension indicating improved bioavailability after formulating SMEDDS. Lymphatic transport in oral absorption of LH-SMEDDS was proved via lymphatic uptake study. All the findings suggest the effectiveness of lipid-based formulation i.e. SMEDDS of LH to augment the oral bioavailability via intestinal lymphatic pathway.

A Simple HPLC Method for the Quantitative Determination of Silybin in Rat Plasma: Application to a Comparative Pharmacokinetic Study on Commercial Silymarin Products

Silybin (SBN) is a major active constituent of silymarin, a mixture of flavonoids found in fruits and seeds of milk thistle. The aim of this study was to describe a simple bioanalytical method for quantifying SBN in rat plasma. A simple protein deproteinization procedure with acetonitrile (ACN) was employed for plasma sample preparation. A reversed column and gradient elution of a mobile phase (mixture of phosphate buffer (pH 5.0) and ACN) were used for chromatographic separation. The selectivity, linearity (50–5000 ng/mL), precision, accuracy, recovery, matrix effect, and stability for this method were validated as per the current Food and Drug Administration (FDA) guidelines. Our method for SBN was applied to a comparative pharmacokinetic study on four different commercial silymarin products. This in vivo rat study demonstrated that product #4 significantly enhanced the relative oral bioavailability of SBN, as compared to product #1–3. Therefore, the bioanalytical method proposed herein could serve as a promising alternative for preclinical pharmacokinetic studies on silymarin products and, by extension, clinical use after partial modification and validation.

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.

Solid Self-Emulsifying Delivery System (S-SEDS) of Dihydromyricetin: A New Way for Preparing Functional Food

The present study was aimed at formulating and evaluating a novel solid self-emulsifying delivery system (S-SEDS) for the application in functional foods of dihydromyricetin (DMY). First, solubility study and pseudo-ternary phase diagram analysis were adopted to optimize the formulation of liquid self-emulsifying delivery system (L-SEDS). And the thermodynamic stable L-SEDS with 5% content of DMY was fabricated and further developed into a solid form via vacuum rotary evaporation with Aerosil 300 as the solid adsorbent. Solid state characterization of the S-SEDS was performed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray powder diffraction. Furthermore, studies proved that the antioxidant activity and bioaccessibility of DMY were improved after incorporated into S-SEDS formulation compared to pure DMY. The S-SEDS showed good resistance against various storage conditions investigated for 10 weeks. PRACTICAL APPLICATION: Solid self-emulsifying delivery system (S-SEDS) combined the advantages of liquid self-emulsifying delivery system with those of a solid dosage form to overcome the disadvantages associated with liquid formulations is more convenient for storage and transportation in practical application. Furthermore, the technology of producing S-SEDS is simple and can be realized in industrial production. Hence, S-SEDS could be a promising strategy to overcome the poor water solubility and short biological half-life of dihydromyricetin for further application in functional foods and beverage industry.

Self-emulsifying drug delivery system: Mucus permeation and innovative quantification technologies

Mucus is a dynamic barrier which covers and protects the underlying mucosal epithelial membrane against bacteria and foreign particles. This protection mechanism extends to include therapeutic macromolecules and nanoparticles (NPs) through trapping of these particles. Mucus is not only a physical barrier that limiting particles movements based on their sizes but it selectively binds with particles through both hydrophilic and lipophilic interactions. Therefore, nano-carriers for mucosal delivery should be designed to eliminate entrapment by the mucus barrier. For this reason, different strategies have been approached for both solid nano-carriers and liquid core nano-carriers to synthesise muco-diffusive nano-carrier. Among these nano-strategies, Self-Emulsifying Drug Delivery System (SEDDS) was recognised as very promising nano-carrier for mucus delivery. The system was introduced to enhance the dissolution and bioavailability of orally administered insoluble drugs. SEDDS has shown high stability against intestinal enzymatic activity and more importantly, relatively rapid permeation characteristics across mucus barrier. The high diffusivity of SEDDS has been tested using various in vitro measurement techniques including both bulk and individual measurement of droplets diffusion within mucus. The selection and processing of an optimum in vitro technique is of great importance to avoid misinterpretation of the diffusivity of SEDDS through mucus barrier. In conclusion, SEDDS is a system with high capacity to diffuse through intestinal mucus even though this system has not been studied to the same extent as solid nano-carriers.

Self-microemulsifying Drug Delivery System for Problematic Molecules: An Update

BACKGROUND

The poor bioavailability of a problematic molecule is predominantly due to its high lipophilicity, low solubility in gastric fluids and/or high fist pass metabolism. Self microemulsifying drug delivery system (SMEDDS), a lipidic type IV nano-formulation has been of interest in the field of pharmaceutical research due to its potential for tailoring the physicochemical properties of pharmaceutical molecules.

METHODS

This review provides insights on various recent innovations and reports from the past seven years (2012-2019) of self-emulsifying formulations for the delivery of various types of poorly soluble drugs, phytoconstituents and high molecular peptides and gives exhaustive details of the outcome of the endeavors in this field.

RESULTS

Various types of innovative formulations have been molded from SMEDDS like selfemulsifying powders, granules, tablets, pellets, eutectic and cationic formulations. Till date, many research reports and patents have been filed on self-emulsifying dosage forms and many formulations have gained US-FDA approvals which are summarized in the review article.

CONCLUSION

This review content highlighted the increasing scope of SMEDDS in augmenting the physiochemical properties of an API, the variegated formulation types and the attributes of API that can be improved by SMEDD based formulations.

Stabilizing supersaturated drug-delivery system through mechanism of nucleation and crystal growth inhibition of drugs

A supersaturated drug-delivery system is capable of enhancing oral bioavailability of hydrophobic drugs. Maintenance of the supersaturated system both in vitro and in vivo is one of the most challenging parts, for that it is required to keenly understand the nucleation and crystal growth behavior. Polymers are widely used to stabilize supersaturated solutions; screening of polymers is done on the basis of their interaction with drug. Nucleation and crystal growth inhibition and drug–polymer interactions can be investigated by using various spectroscopic methods. Various formulations are prepared as supersaturated systems using different drug-delivery systems utilizing different polymers, which illustrates that supersaturation is worthwhile to increase the solubility and hence oral bioavailability of poorly soluble drugs.

Polymeric Precipitation Inhibitors Promote Fenofibrate Supersaturation and Enhance Drug Absorption from a Type IV Lipid-Based Formulation

The ability of lipid-based formulations (LBFs) to increase the solubilization, and prolong the supersaturation, of poorly water-soluble drugs (PWSDs) in the gastrointestinal (GI) fluids has generated significant interest in the past decade. One mechanism to enhance the utility of LBFs is to prolong supersaturation via the addition of polymers that inhibit drug precipitation (polymeric precipitation inhibitors or PPIs) to the formulation. In this work, we have evaluated the performance of a range of PPIs and have identified PPIs that are sufficiently soluble in LBF to allow the construction of single phase formulations. An in vitro model was first employed to assess drug (fenofibrate) solubilization and supersaturation on LBF dispersion and digestion. An in vitro-in situ model was subsequently employed to simultaneously evaluate the impact of PPI enhanced drug supersaturation on drug absorption in rats. The stabilizing effect of the polymers was polymer specific and most pronounced at higher drug loads. Polymers that were soluble in LBF allowed simple processing as single phase formulations, while formulations containing more hydrophilic polymers required polymer suspension in the formulation. The lipid-soluble polymers Eudragit (EU) RL100 and poly(propylene glycol) bis(2-aminopropyl ether) (PPGAE) and the water-soluble polymer hydroxypropylmethyl cellulose (HPMC) E4M were identified as the most effective PPIs in delaying fenofibrate precipitation in vitro. An in vitro model of lipid digestion was subsequently coupled directly to an in situ single pass intestinal perfusion assay to evaluate the influence of PPIs on fenofibrate absorption from LBFs in vivo. This coupled model allowed for real-time evaluation of the impact of supersaturation stabilization on absorptive drug flux and provided better discrimination between the different PPIs and formulations. In the presence of the in situ absorption sink, increased fenofibrate supersaturation resulted in increased drug exposure, and a good correlation was found between the degree of in vitro supersaturation and in vivo drug exposure. An improved in vitro-in vivo correlation was apparent when comparing the same formulation under different supersaturation conditions. These observations directly exemplify the potential utility of PPIs in promoting drug absorption from LBF, via stabilization of supersaturation, and further confirm that relatively brief periods of supersaturation may be sufficient to promote drug absorption, at least for highly permeable drugs such as fenofibrate.

Enhanced Oral Bioavailability of Curcumin Using a Supersaturatable Self-Microemulsifying System Incorporating a Hydrophilic Polymer; In Vitro and In Vivo Investigations

A supersaturatable self-microemulsifying drug delivery system (S-SMEDDS) with a reduced amount of surfactant and incorporation of a polymer precipitation inhibitor, Eudragit® E PO was developed. The optimized S-SMEDDS formulation (SS-15) consisted of 55% surfactants, 40% oils, and 5% Eudragit® E PO (curcumin at 44.4 mg/g of the formulation). The precipitation profiles from the supersaturation assay revealed that the curcumin S-SMEDDS performed as a better inhibitor of curcumin precipitation in simulated gastric fluid over a 240-min study than the normal curcumin SMEDDS and an aqueous curcumin suspension. In addition, the mean droplet size of the curcumin S-SMEDDS (21.6 ± 0.1 nm) was significantly smaller than the SMEDDS (28.1 ± 0.3 nm). The curcumin S-SMEDDS exhibited a threefold reduction of Caco-2 cell toxicity when compared to the curcumin SMEDDS because of the reduced toxic effect of the surfactant present in the SMEDDS formulation. In addition, the absorptive permeability across the Caco-2 monolayer of curcumin in the S-SMEDDS was significantly higher than for the unformulated curcumin (~ 5-folds). The plasma concentration-time profiles from the oral absorption studies in rats dosed with the curcumin S-SMEDDS showed a 1.22- and 53.14-fold increased absorption of curcumin, compared to the SMEDDS and the aqueous suspension, respectively. The curcumin S-SMEDDS was stable under both intermediate and accelerated conditions after 6 months of storage.

The efficiency and mechanism of N-octyl-O, N-carboxymethyl chitosan-based micelles to enhance the oral absorption of silybin

This study demonstrates the preparation of a silybin-loaded N-octyl-O, N-carboxymethyl chitosan micelle (OCC-SLB) to enhance the oral absorption efficiency of silybin (SLB) and investigate the related mechanisms of enhancement. Firstly, the physicochemical properties of OCC and OCC-SLB micelles, including critical micelle concentration (CMC), particle size, zeta potential, drug-loading, etc., were determined. Results of pharmacokinetic studies on rats then confirmed a desirable enhancement in the oral bioavailability of SLB by OCC-SLB micelles compared with a stock SLB suspension solution. Subsequently, uptake studies on the Caco-2 cell line demonstrated that OCC-SLB micelles effectively accumulated SLB or rhodamine-123 into cells through clathrin and caveolae-mediated endocytosis and the inhibition of P-glycoprotein (P-gp) efflux. In addition, results of the Caco-2 transport study further clarified that OCC-SLB micelles enhanced the permeability of SLB via tight junction opening and clathrin-mediated transcytosis across the endothelium. These findings indicated the OCC micelle platform as a potential delivery vehicle for oral administration of P-gp substrates such as SLB.

Self-Emulsifying Granules and Pellets: Composition and Formation Mechanisms for Instant or Controlled Release

Many articles have been published in the last two decades demonstrating improvement in the dissolution and absorption of low solubility drugs when formulated into self-emulsifying drug delivery systems (SEDDS). Several such pharmaceutical products have appeared in the market for medium dose (Neoral^® for Cyclsoprin A, Kaletra^® for Lopinavir and Ritonavir), or low dose medications (Rocaltrol^® for Calcitriol and Avodart^® for Dutasteride). However, these are in the form of viscous liquids or semisolid presentations, characterized by the disadvantages of high production cost, stability problems and the requirement of large quantities of surfactants. Solid SEDDS (S-SEDDS), as coarse powders, granules or pellets, besides solubility improvement, can be filled easily into capsules or processed into tablets providing a handy dosage form with instant release, which can be further developed into controlled release by mixing with suitable polymers or coating with polymeric films. In this review, the materials used for the preparation of S-SEDDS, their properties and role in the formulations are detailed. Factors affecting the physical characteristics, mechanical properties of S-SEDDS as well as their in vitro release and in vivo absorption are discussed. The mechanisms involved in the formation of instant and sustained release self-emulsifying granules or pellets are elucidated. Relationships are demonstrated between the characteristics of S-SEDDS units (size, shape, mechanical properties, re-emulsification ability, drug migration and drug release) and the properties of the submicron emulsions used as massing liquids, with the aim to further elucidate the formation mechanisms. The influence of the composition of the powdered ingredients forming the granule or pellet on the properties of S-SEDDS is also examined. Examples of formulations of S-SEDDS that have been reported in the literature in the last thirteen years (2004–2017) are presented.

Preparation and evaluation of Vinpocetine self-emulsifying pH gradient release pellets

The main objective of this study was to develop a pH gradient release pellet with self-emulsifying drug delivery system (SEDDS), which could not only improve the oral bioavailability of Vinpocetine (VIN), a poor soluble drug, but reduce the fluctuation of plasma concentration. First, the liquid VIN SEDDS formulation was prepared. Then the self-emulsifying pH gradient release pellets were prepared by extrusion spheronization technique, and formulation consisted by the liquid SEDDS, absorbent (colloidal silicon dioxide), penetration enhancer (sodium chloride), microcrystalline cellulose, ethyl alcohol, and three coating materials (HPMC, Eudragit L30D55, Eudragit FS30D) were eventually selected. Three kinds of coated pellets were mixed in capsules with the mass ratio of 1:1:1. The release curves of capsules were investigated in vitro under the simulated gastrointestinal conditions. In addition, the oral bioavailability and pharmacokinetics of VIN self-emulsifying pH gradient release pellets, commercial tablets and liquid VIN SEDDS were evaluated in Beagle dogs. The oral bioavailability of self-emulsifying pH gradient release pellets was about 149.8% of commercial VIN tablets, and it was about 86% of liquid VIN SEDDS, but there were no significant difference between liquid SEDDS and self-emulsifying pH gradient release pellets. In conclusion, the self-emulsifying pH gradient release pellets could significantly enhance the absorption of VIN and effectively achieve a pH gradient release. And the self-emulsifying pH gradient release pellet was a promising method to improve bioavailability of insoluble drugs.

Patient-centered drug delivery and its potential applications for unmet medical needs

Pharmaceutical dosage forms address diverse key components but satisfying unmet patient needs to enhance patient adherence is a major challenge. The desired design of patient-centered drug products should be based on characteristics of various components, such as patients, disease, routes of administration, drug delivery technologies and active pharmaceutical ingredients. Understanding of targeting patients and their physiological and biological environments is pivotal for developing suitable patient-centered drug products. In this review, key components of an ideal drug delivery system were considered. Then, stepwise approaches for designing patient-centered drug products were suggested. Finally, various case studies are also presented and considered to develop models of patient-centered drug products.

Skin Delivery of EGCG and Silibinin: Potential of Peptide Dendrimers for Enhanced Skin Permeation and Deposition

The aim of the present study was to evaluate the ability of the peptide dendrimers to facilitate transdermal delivery of antioxidants, silibinin, and epigallocatechin-3-gallate (EGCG). Drug-peptide dendrimer complexes were prepared and evaluated for their ability to permeate across the skin. The data revealed the ready formation of complexes between drug and peptide dendrimer in a molar ratio of 1:1. In vitro permeation studies using excised rat skin and drug-peptide dendrimer complexes showed highest values for cumulative drug permeation at the end of 12 h (Q₁₂), with corresponding permeability coefficient (Kp) and enhancement ratio values also determined at this time point. With silibinin, 3.96-, 1.81-, and 1.06-fold increase in skin permeation was observed from silibinin-peptide dendrimer complex, simultaneous application of silibinin + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. With EGCG, 9.82-, 2.04-, and 1.72-fold increase in skin permeation was observed from EGCG-peptide dendrimer complex, simultaneous application of EGCG + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. The present study demonstrates the application of peptide dendrimers in effectively delivering antioxidants such as EGCG and silibinin into the skin, thus offering the potential to provide antioxidant effects when delivered via appropriately formulated topical preparations.

Systematic development of design of experiments (DoE) optimised self-microemulsifying drug delivery system of Zotepine

The aim of present investigation is to improve dissolution rate of poor soluble drug Zotepine by a self-microemulsifying drug delivery system (SMEDDS). Ternary phase diagram with oil (Oleic acid), surfactant (Tween 80) and co-surfactant (PEG 400) at apex were used to identify the efficient self-microemulsifying region. Box-Behnken design was implemented to study the influence of independent variables. Principal Component Analysis was used for scrutinising critical variables. The liquid SMEDDS were characterised for macroscopic evaluation, % Transmission, emulsification time and in vitro drug release studies. Optimised formulation OL1 was converted in to S-SMEDDS by using Aerosil^® 200 as an adsorbent in the ratio of 3:1. The S-SMEDDS was characterised by SEM, DSC, globule size (152.1 nm), zeta-potential (-28.1 mV), % transmission study (98.75%), in vitro release (86.57%) at 30 min. The optimised solid SMEDDS formulation showed faster drug release properties as compared to conventional tablet of Zotepine.

Nanoemulsifying drug delivery system to improve the bioavailability of piroxicam

OBJECTIVE

The aim of this study is to develop and characterize self-nanoemulsifying drug delivery system (SNEDDS) of piroxicam in liquid and solid forms to improve its dissolution, absorption and therapeutic efficacy.

MATERIALS AND METHODS

The generation of liquid SNEDDS (L-SNEDDS) was composed of soybean or coconut oil/Tween 80/Transcutol HP (12/80/8%w/w) and it was selected as the optimized formulation based on the solubility study and pseudo-ternary phase diagram. Optimized L-SNEDDS and liquid supersaturatable SNEDDS (L-sSNEDDS) preparations were then adsorbed onto adsorbents and formulated as directly compressed tablets.

RESULTS AND DISCUSSION

The improved drug dissolution rate in the solid supersaturatable preparation (S-sSNEDDS) may be due to the formation of a nanoemulsion and the presence of drug in an amorphous state with hydrogen bond interaction between the drug and SNEDDS components. In vivo pharmacokinetic studies on eight healthy human volunteers showed a significant improvement in the oral bioavailability of piroxicam from S-sSNEDDS (F12) compared with both the pure drug (PP) and its commercial product (Feldene^®) (commercial dosage form (CD)). The relative bioavailability of S-sSNEDDS (F12) relative to PP or CD was about 151.01 and 98.96%, respectively.

CONCLUSION

The obtained results ratify that S-sSNEDDS is a promising drug delivery system to enhance the oral bioavailability of piroxicam.

In Vitro Release and Bioavailability of Silybin from Micelle-Templated Porous Calcium Phosphate Microparticles

Developing a promising carrier for the delivery of poorly water-soluble drugs, such as silybin, to improve oral absorption has become a very worthy of consideration. The goal of this study was to prepare a novel porous calcium phosphate microparticle using povidone-mixed micelles as template while evaluating its in vitro and in vivo properties with silybin as a model drug. The particle characterization, in vitro drug release behavior, and pharmacokinetic parameters of the prepared silybin-loaded calcium phosphate microparticle were investigated. The mean particle size was found to be 3.54 ± 0.32 μm with a rough surface porous structure. Additionally, the silybin-loaded calcium phosphate microparticle compared with the free silybin showed a prolonged 72-h release in vitro and a higher C max (418.5 ± 23.7 ng mL(-1)) with 167.5% oral relative bioavailability. A level A in vitro-in vivo correlation (IVIVC), established for the first time, demonstrated an excellent IVIVC of the formulated silybin in oral administration. In conclusion, this povidone-mixed micelle-based microparticle was successfully prepared to enhance the oral bioavailability of silybin. Therefore, application of this novel porous calcium phosphate microparticle holds a significant potential for the development of poorly water-soluble drugs.