Self-nano-emulsifying drug delivery systems: an update of the biopharmaceutical aspects

Factors and dosage formulations affecting the solubility and bioavailability of P-glycoprotein substrate drugs

Introduction: Expression of P-glycoprotein (P-gp) increases toward the distal small intestine, implying that the duodenum is the preferential absorption site for P-gp substrate drugs. Oral bioavailability of poorly soluble P-gp substrate drugs is low and varied but increases with high-fat meals that supply lipoidal components and bile in the duodenum.Areas covered: Absorption properties of P-gp substrate drugs along with factors and oral dosage formulations affecting their solubility and bioavailability were reviewed with PubMed literature searches. An overview is provided from the viewpoint of the 'spring-and-parachute approach' that generates supersaturation of poorly soluble P-gp substrate drugs.Expert opinion: The oral bioavailability of P-gp substrate drugs is difficult to predict because of their low solubility, preferential absorption sites, and overlapping substrate specificities with CYP3A4, along with the scattered intestinal P-gp expression/function. To attain high and steady oral bioavailability of poorly soluble P-gp substrate drugs, physicochemical modification of drugs to improve solubility, or oral dosage formulations that generate long-lasting supersaturation in the duodenum, is preferred. In particular, supersaturable lipid-based drug delivery systems that can increase passive diffusion and/or lymphatic absorption are effective and applicable to many poorly soluble P-gp substrate drugs.

Recent Developments in Solid Lipid Microparticles for Food Ingredients Delivery

Health food has become a prominent force in the market place, influencing many food industries to focus on numerous bioactive compounds to reap benefits from its properties. Use of these compounds in food matrices has several limitations. Most of the food bio-additives are sensitive compounds that may quickly decompose in both food and within the gastrointestinal tract. Since most of these bioactives are highly or partially lipophilic molecules, they possess very low water solubility and insufficient dispersibility, leading to poor bioavailability. Thus, various methods of microencapsulation of large number of food bioactives have been studied. For encapsulation of hydrophobic compounds several lipid carriers and lipid platforms have been studied, including emulsions, microemulsions, micelles, liposomes, and lipid nano- and microparticles. Solid lipid particles (SLP) are a promising delivery system, can both deliver bioactive compounds, reduce their degradation, and permit slow and sustained release. Solid lipid particles have important advantages compared to other polymer carriers in light of their simple production technology, including scale up ability, higher loading capacity, extremely high biocompatibility, and usually low cost. This delivery system provides improved stability, solubility in various matrixes, bioavailability, and targeting properties. This article reviews recent studies on microencapsulation of selected bioactive food ingredients in solid lipid-based carriers from a point of view of production methods, characteristics of obtained particles, loading capability, stability, and release profile.

Bortezomib-loaded lipidic-nano drug delivery systems; formulation, therapeutic efficacy, and pharmacokinetics

AIM

Nano drug delivery systems can provide the opportunity to reduce side effects and improve the therapeutic aspect of a variety of drugs. Bortezomib (BTZ) is a proteasome inhibitor approved for the treatment of multiple myeloma and mantle cell lymphoma. Severe side effects of BTZ are the major dose-limiting factor. Particulate drug delivery systems for BTZ are polymeric and lipidic drug delivery systems. This review focussed on lipidic-nano drug delivery systems (LNDDSs) for the delivery of BTZ.

RESULTS

LNDDSs including liposomes, solid lipid nanoparticles, and self-nanoemulsifying drug delivery systems showed reduce systemic side effects, improved therapeutic efficacy, and increased intestinal absorption. Besides LNDDSs were used to target-delivery of BTZ to cancer.

CONCLUSION

Overall, LNDDSs can be considered as a novel delivery system for BTZ to resolve the treatment-associated restrictions.

Oral Nano Drug Delivery Systems for the Treatment of Type 2 Diabetes Mellitus: An Available Administration Strategy for Antidiabetic Phytocompounds

In view of the worldwide serious health threat of type 2 diabetes mellitus (T2DM), natural sources of chemotherapies have been corroborated as the promising alternatives, with the excellent antidiabetic activities, bio-safety, and more cost-effective properties. However, their clinical application is somewhat limited, because of the poor solubility, instability in the gastrointestinal tract (GIT), low bioavailability, and so on. Nowadays, to develop nanoscaled systems has become a prominent strategy to improve the drug delivery of phytochemicals. In this review, we primarily summarized the intervention mechanisms of phytocompounds against T2DM and presented the recent advances in various nanosystems of antidiabetic phytocompounds. Selected nanosystems were grouped depending on their classification and structures, including polymeric NPs, lipid-based nanosystems, vesicular systems, inorganic nanocarriers, and so on. Based on this review, the state-of-the-art nanosystems for phytocompounds in T2DM treatment have been presented, suggesting the preponderance and potential of nanotechnologies.

Self-Nano-Emulsifying Drug-Delivery Systems: From the Development to the Current Applications and Challenges in Oral Drug Delivery

Approximately one third of newly discovered drug molecules show insufficient water solubility and therefore low oral bio-availability. Self-nano-emulsifying drug-delivery systems (SNEDDSs) are one of the emerging strategies developed to tackle the issues associated with their oral delivery. SNEDDSs are composed of an oil phase, surfactant, and cosurfactant or cosolvent. SNEDDSs characteristics, their ability to dissolve a drug, and in vivo considerations are determinant factors in the choice of SNEDDSs excipients. A SNEDDS formulation can be optimized through phase diagram approach or statistical design of experiments. The characterization of SNEDDSs includes multiple orthogonal methods required to fully control SNEDDS manufacture, stability, and biological fate. Encapsulating a drug in SNEDDSs can lead to increased solubilization, stability in the gastro-intestinal tract, and absorption, resulting in enhanced bio-availability. The transformation of liquid SNEDDSs into solid dosage forms has been shown to increase the stability and patient compliance. Supersaturated, mucus-permeating, and targeted SNEDDSs can be developed to increase efficacy and patient compliance. Self-emulsification approach has been successful in oral drug delivery. The present review gives an insight of SNEDDSs for the oral administration of both lipophilic and hydrophilic compounds from the experimental bench to marketed products.

Resveratrol: nanocarrier-based delivery systems to enhance its therapeutic potential

Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic compound existing in trees, peanuts and grapes and exhibits a broad spectrum of promising therapeutic activities, but it is unclear whether this entity targets the sites of action after oral administration. In vivo applicability of resveratrol has limited success so far, mainly due to its incompetent systemic delivery resulting from its low water solubility, poor bioavailability and short biological half-life. First-pass metabolism and presence of enterohepatic recirculation create doubt on the biological application of high doses typically used for in vitro trials. To augment bioavailability, absorption and uptake of resveratrol by cellular internalization, countless approaches have been implemented which involve the use of nanocarriers. Nanocarriers are a well-known delivery system used to reduce first-pass hepatic metabolism, overcome enterohepatic recirculation and accelerate the absorption of drugs via lymphatic pathways.

Enhancement of oral bioavailability of drugs using lipid-based carriers: a meta-analysis study

Cancer is the disease of this era. Its therapy is moving through ups and downs not only due to poor effectiveness of many treating drugs, but also due to the serious side effects always evolving. In an attempt to overcome this problem, many systems, including lipid-based carriers, have been exploited for their oral delivery. Throughout this study, the meta-analysis tool was used to combine data from different studies and extract evidences that lipid-based carriers enhance the oral bioavailability. Consequently, increasing the efficiency and the reduction in side effects of drugs would follow. Accordingly, the usual parameter to indicate the bioavailability; the area under effect curve (AUC) was used where the lipid carriers have proven their superiority over conventional formulations. Interestingly, by comparing microemulsion/self-microemulsifying system (SMEDDS) versus liposomes/pro-liposomes as subgroups of the meta-analysis study, insignificant differences were recorded between them.

Evaluation of the hypoglycemic effect of exendin-4's new oral self-nanoemulsifying system in rats

The objective of this study is to develop a new self-nanoemulsifying system containing exendin-4 with or without enzyme inhibitor chymostatin and to evaluate the effects of oral administration of exendin-4 and exendin-4/chymostatin loaded self nanoemulsifying system on plasma exendin-4, plasma insulin, blood glucose levels and to compare with the oral and subcutaneous administration of exendin-4 in non-diabetic and streptozotocin-induced type 2 diabetic rats. Exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying system containing ethyl oleate as the oil phase, Cremophor EL®/Labrasol® as the surfactants and propylene glycol as the co-solvent were prepared. The mean droplet size, polydispersity index, zeta potential and viscosity of exendin-4 loaded self-nanoemulsifying system were found as 24.28 ± 0.43 nm, 0.17 ± 0.01, -1.28 ± 3.61 mV, 79.60 ± 3.30 m.Pas, respectively. The mean droplet size, polydispersity index, zeta potential and viscosity of exendin-4/chymostatin loaded self-nanoemulsifying system were found as 20.25 ± 0.35 nm, 0.11 ± 0.02, -1.85 ± 2.49 mV, 100.02 ± 7.65 m.Pas, respectively according to our previous study. In the present study, we focused on long-term physical stability studies, pharmacokinetic studies and pharmacodynamic studies of prepared self-nanoemulsifying systems. According to the long- term physical stability data, exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying systems were found stable both at 5°C ± 3°C and at 25°C ± 60% RH for 12 months. Exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying systems increased AUC and C_max values in non-diabetic rats compared to the oral exendin-4 solution. In diabetic rats, exendin-4/chymostatin loaded self nanoemulsifying systems increased C_max values compared to the exendin-4 solution. Exendin-4/chymostatin loaded self-nanoemulsifying system decreased inter-subject variability compared to commercial Byetta®. At 30^th minute after administration of exendin-4 loaded self-nanoemulsifying system, exendin-4/chymostatin loaded self nanoemulsifying system and Byetta®, blood glucose levels decreased to 23%, 25%, 29%, respectively. It has been shown that pharmacodynamic response is close to Byetta® with exendin-4/chymostatin self-nanoemulsifying system oral administration. In conclusion, a self nanoemulsifying system was found to be a suitable carrier system, and the combination with enzyme inhibitor chymostatin is thought to be promising for oral delivery of exendin-4.

Solid Self-Emulsifying Drug Delivery System (Solid SEDDS) for Testosterone Undecanoate: In Vitro and In Vivo Evaluation

OBJECTIVE

The current study aimed to investigate the potential of Solid Self-Emulsifying Drug Delivery Systems (solid SEDDS) loaded with Testosterone Undecanoate (TU) (solid TUSEDDS). The solid TU-SEDDS was composed of TU, Medium-Chain Triglycerides (MCT, oil), 2- Chloro-1-(chloromethyl) ethyl carbamate (EL-35, surfactant) and polyethylene glycol (PEG400, cosurfactant). It was expected to improve the dissolution and oral bioavailability of TU, as a result of investigating the feasibility of the clinical application of SEDDS.

METHODS

First, a TU-SEDDS was developed by using rational blends of components with the good solubilizing ability for TU. Next, a ternary phase diagram was constructed to determine the self-emulsifying region, and the formulation was optimized. Then, the solid TU-SEDDS formulation was established by screening suitable solid adsorptions. Finally, the prepared SEDDS, TUSEDDS and solid TU-SEDDS formulations were evaluated in vitro and in vivo.

RESULTS

The size of the solid TU-SEDDS was 189.1 ± 0.23 nm. The Transmission Electron Microscopy (TEM) results showed that the oil droplets were homogenous and spherical with good integrity. The Differential Scanning Calorimetry (DSC) and X-Ray Powder Dffraction (XRD) results indicated that the solid TU-SEDDS formulation almost preserves the amorphous state. Scanning Electron Microscopy (SEM) indicated that neusilin US2 successfully adsorbed the TU-SEDDS. Drug release indicated that the dissolution of the solid TU-SEDDS was faster than that of Andriol Testocaps ®. Furthermore, in vivo pharmacokinetic (PK) studies in Sprague-Dawley (SD) rats showed that the Area Under the Curve (AUC) of the solid TU-SEDDS (487.54±208.80 μg/L×h) was higher than that of Andriol Testocaps® (418.93±273.52 μg/L×h, P < 0.05). In beagles not fed a high-fat diet, the AUC of the solid TU-SEDDS (5.81±4.03 μg/L×h) was higher than that of Andriol Testocaps ® (5.53±3.43 μg/L×h, P > 0.05). In beagles fed a high-fat diet, the AUC of the solid TUSEDDS (38.18±21.90 μg/L×h) was higher than that of Andriol Testocaps® (37.17±13.79 μg/L×h, P > 0.05).

CONCLUSION

According to the results of this research, oral solid TU-SEDDS is expected to be another alternative delivery system for the late-onset hypogonadism. This is beneficial to the transformation of existing drug delivery systems into preclinical and clinical studies.

The Solubility-Permeability Interplay for Solubility-Enabling Oral Formulations

The Biopharmaceutical classification system (BCS) classifies the drugs based on their intrinsic solubility and intestinal permeability. The drugs with good solubility and intestinal permeability have good bioavailability. The drugs with poor solubility and poor permeability have solubility dependent and permeability dependent bioavailability, respectively. In the current pharmaceutical field, most of the drugs have poor solubility. To solve the problem of poor solubility, various solubility enhancement approaches have been successfully used. The effects of these solubility enhancing approaches on the intestinal permeability of the drugs are a matter of concern, and must not be overlooked. The current review article focuses on the effect of various solubility enhancing approaches viz. cyclodextrin, surfactant, cosolvent, hydrotropes, and amorphous solid dispersion, on the intestinal permeability of drugs. This article will help in the designing of the optimized formulations having balanced solubility enhancement without affecting the permeability of drugs.

Lipid Drug Carriers for Cancer Therapeutics: An Insight into Lymphatic Targeting, P-gp, CYP3A4 Modulation and Bioavailability Enhancement

In the treatment of cancer, chemotherapy plays an important role though the efficacy of anti-cancer drug administered orally is limited, due to their poor solubility in physiological medium, inability to cross biological membrane, high Para-glycoprotein (P-gp) mediated drug efflux, and pre-systemic metabolism. These all factors cumulatively reduce drug exposure at the target site leading to multidrug resistance (MDR). Lipid based carriers systems has been explored to overcome solubility and permeability related issues of anti-cancer drugs. The lipid based formulations have also been reported to circumvent the effect of P-gp and CYP3A4. Further long chain triglycerides (LCT) has shown their ability to access Lymphatic route over Medium Chain Triglycerides, as the former has been extensively used for targeting anti-cancer drugs at proliferating cells through lymphatic route. Therefore this review tries to reflect the usefulness of lipid based drug carriers systems (viz. liposome, solid lipid nanoparticle, nano-lipid carriers, self-emulsifying, lipidic pro-drugs) in targeting lymphatic system and overcoming issues related to solubility and permeability of anti-cancer drugs. Moreover, we have also tried to reflect how critically lipid based carriers are important in maximizing therapeutic safety and efficacy of anti-cancer drugs.

Pharmacokinetic investigation of synthetic cannabidiol oral formulations in healthy volunteers

Recent advances in the research of medicinal cannabis has placed the non-intoxicating cannabinoid cannabidiol (CBD) at the front of scientific research. The reasons behind this popularity is the compound's therapeutic properties, alongside a safe profile of administration lacking addictive properties such as euphoric state of mind and a wide dosing range. Oral administration of CBD is challenging due to poor solubility in the gastro-intestinal system and susceptibility to extensive first pass metabolism. As a result, the practice in clinic and investigational trials is to administer cannabinoids in edible oils or oil-based solutions. Nonetheless, reported pharmacokinetics of cannabinoids and CBD in particular are not uniform among research groups and are affected by the vehicle of administration. The purpose of the work presented here is to investigate oral absorption processes of synthetic CBD when given in different oral formulations in healthy volunteers. The study design was a three way, blind, cross-over single administration study of 12 healthy male volunteers. CBD was administered in powder form, dissolved in sesame oil and in self-nano-emulsifying drug delivery system (SNEDDS). Administration of CBD in lipid-based vehicles resulted in a significant increase in C_max and AUC of CBD, as compared to powder form. Overall plasma exposure of CBD did not differ between sesame oil vehicle and the SNEDDS formulation. However, administration of CBD in pure oil resulted in two absorption behaviors of early and delayed absorption among subjects, as opposed to SNEDDS platform that resulted in a uniform early absorption profile. Results of this trial demonstrate the importance of solubilization process of lipophilic drugs such as CBD and demonstrated the ability of the nano formulation to achieve a reliable, predictable PK profile of the drug. These findings offer a standardized oral formulation for the delivery of cannabinoids and contribute data for the growing field of cannabinoid pharmacokinetics.

Novel self-nanoemulsifying drug-delivery system enhances antileukemic properties of all-trans retinoic acid

Aim: All- trans retinoic acid (ATRA) shows erratic oral bioavailability when administered orally against leukemia, which can be solved through its incorporation in self-nanoemulsifying drug-delivery systems (SEDDS). The SEDDS developed contained a hydrophobic ion pair between benzathine (BZT) and ATRA and was enriched with tocotrienols by the input of a palm oil tocotrienol rich fraction (TRF) in its composition. Results: SEDDS-TRF-ATRA-BZT allowed the formation of emulsions with nanometric size that retained ATRA within their core after dispersion. Pharmacokinetic parameters after oral administration of SEDDS-TRF-ATRA-BZT in mice were improved compared with what was seen for an ATRA solution. Moreover, SEDDS-TRF-ATRA-BZT had improved activity against HL-60 cells compared with SEDDS without TRF. Conclusion: SEDDS-TRF-ATRA-BZT is a promising therapeutic choice over ATRA conventional medicine.

Benznidazole self-emulsifying delivery system: A novel alternative dosage form for Chagas disease treatment

Benznidazole (BZ) tablets are a unique form of treatment available for treating Chagas disease. Development of a liquid formulation containing BZ easy to administer orally for the treatment of paediatric patients, particularly for newborns is urgently required, with the same efficacy, safety and suitable biopharmaceutical properties as BZ tablets. Self-emulsifying drug delivery systems (SEDDS) may improve bioavailability of drugs such as BZ, which have poor water solubility and low permeability. In this context, the aim of this work was to develop a liquid BZ-SEDDS formulation as an alternative to tablets and to evaluate its cytotoxicity in different host cell lines and its efficacy in experimental Trypanosoma cruzi infection in mice. The optimized SEDDS formulation (25 mg/ml of BZ) induced no cytotoxicity in H9c2, HepG2 and Caco2 cells in vitro at 25 μM level. BZ-SEDDS and free-BZ showed similar in vitro trypanocidal activity in H9c2 cells infected by T. cruzi Y strain, with IC₅₀ values of 2.10 ± 0.41 μM and 1.29 ± 0.01 μM for BZ and BZ-SEDDS, respectively. A follow up of efficacy in an acute model of infected mice resulted in the same percentage of cure (57%) for both free-BZ and BZ-SEDDS- groups according to established parameters. Furthermore, no additional in vivo toxicity was observed in animals treated with BZ-SEDDS. Taken together, in vitro and in vivo data of BZ-SEDDS showed that the incorporation of BZ into SEDDS does not alter its potency, efficacy and safety. Thus, BZ-SEDDS can be a more practical and personalized orally administered liquid dosage form compared to suspension of crushed BZ-tablets to treat newborn and young children by emulsifying SEDDS in different aqueous liquids with advantage of dosing flexibility.

Attenuation of Benign Prostatic Hyperplasia by Optimized Tadalafil Loaded Pumpkin Seed Oil-Based Self Nanoemulsion: In Vitro and In Vivo Evaluation

The FDA has approved tadalafil (TDL) for the treatment of benign prostatic hyperplasia (BPH)-associated symptoms. Pumpkin seed oil (PSO) has shown promise for the relief of prostatitis-related lower urinary tract symptoms. The aim was to improve TDL delivery to the prostate and assess the combined effect of TDL with a PSO-based formula in the management of BPH. PSO, Tween 80, and polyethylene glycol 200 were selected for the optimization of self nano-emulsified drug delivery system (SNEDDS). The formed vesicles were assessed for their globule size and zeta potential. A rat in vivo study was carried out to investigate prostate weight and index, histopathology, and pharmacokinetics. The average globule size for the optimized TDL-PSO SNEDDS was 204.8 ± 18.76 nm, with a zeta-potential value of 7.86 ± 1.21 mV. TDL-PSO SNEDDS produced a marked drop in prostate weight by 35.51% and prostate index by 36.71% compared to the testosterone-only group. Pharmacokinetic data revealed a 2.3-fold increase of TDL concentration, from optimized TDL-PSO SNEDDS, in the prostate compared with the raw TDL group. This study indicated that the combination of TDL and PSO in an optimized TDL PSO SNEDDS formula improved the efficacy of TDL in the management of BPH.

Physiological and Pharmaceutical Considerations for Rectal Drug Formulations

Although the oral route is the most convenient route for drug administration, there are a number of circumstances where this is not possible from either a clinical or pharmaceutical perspective. In these cases, the rectal route may represent a practical alternative and can be used to administer drugs for both local and systemic actions. The environment in the rectum is considered relatively constant and stable and has low enzymatic activity in comparison to other sections of the gastrointestinal tract. In addition, drugs can partially bypass the liver following systemic absorption, which reduces the hepatic first-pass effect. Therefore, rectal drug delivery can provide significant local and systemic levels for various drugs, despite the relatively small surface area of the rectal mucosa. Further development and optimization of rectal drug formulations have led to improvements in drug bioavailability, formulation retention, and drug release kinetics. However, despite the pharmaceutical advances in rectal drug delivery, very few of them have translated to the clinical phase. This review will address the physiological and pharmaceutical considerations influencing rectal drug delivery as well as the conventional and novel drug delivery approaches. The translational challenges and development aspects of novel formulations will also be discussed.

Enhanced Release Kinetics and Stability of Resveratrol Loaded Self Nanoemulsifying Delivery Systems Developed using Experimental Design

Background:

Resveratrol is a member of the stilbene family emerged as a leading candidate for improving healthspan through potentially slowing the aging process and preventing chronic diseases. A number of institutions and scientists specialized in this field across the world are working to develop a promising Self Emulsifying formulation to enhance bioavailability of hydrophobic resveratrol using oil.

Objective:

The objective of the current study is to develop self-nano emulsifying drug delivery systems using long-chain triglycerides of resveratrol to enhance solubility, stability, release kinetics and to overcome low bioavailability.

Methods:

Solubility studies performed in different lipids, surfactants and cosurfactants. Phase diagrams constructed to select the areas of nanoemulsion. SNEDDS formulation was optimized using 33 central composite design considering lipid (X1), surfactant (X2) and co-surfactant (X3) as critical variables, optimized formulation was located using overlay plot.

Results:

The nanometer size and high values of zeta potential depicted non-coalescent nature of SNEDDS. The resulted SNEDDS formulation had improved in vitro release followed by Hixson Crowell model with higher regression R2value 0. 929. Thermodynamic stability studies ascertained stable formulation. Mean droplet size in selected nanocarrier was found to be 83.29 nm. The nanocarriers subjected to 2-8°C (45% RH), 25-30°C (60% RH) and 45-50°C (75% RH) in glass vials exhibited no significant changes in 3 months.

Conclusion:

The novel approach was developed by selecting optimum blends of lipids, surfactants and cosurfactant using central composite design. This study not only offers a good example of augmenting bioavailability of resveratrol but will also provide a promising oral formulation for clinical application.

Solid dispersions of telaprevir with improved solubility prepared by co-milling: formulation, physicochemical characterization, and cytotoxicity evaluation

Telaprevir (TVR) is typically a poorly soluble drug with an extremely low bioavailability of 1.7%. Polymorph modifications cannot improve the solubility of TVR because it only has a single unsolvated crystalline form. Co-crystals also provide limited bioavailability enhancement for TVR. Thus, in this study, we increased the solubility and dissolution rate of TVR through formulations of TVR-polymer solid dispersions. Three solid dispersions of TVR were successfully prepared by co-milling with polyvinylpyrrolidone K30 (PVP), polyethylene glycol 6000, and hydroxypropyl methylcellulose (HPMC), which were characterized by different techniques. According to X-ray powder diffraction and differential scanning calorimetry results, TVR presented in amorphous form in all solid dispersions. The fourier transform infrared spectra results indicated that TVR may connect with polymers through the N-H···O or O-H···O hydrogen bonds, which were verified by molecular docking. TVR-PVP and TVR-HPMC displayed a good stability at conventional RH levels, and their thermostabilities were better than those of milled TVR. Among the three solid dispersions, TVR-HPMC showed significant solubility and dissolution rate advantages in different media. Moreover, TVR-HPMC displayed the same anticancer efficacy with crystalline TVR and presented no toxic side effects to normal liver cells. Thus, TVR-HPMC showed potential application value.

Comparisons of in vitro Fick's first law, lipolysis, and in vivo rat models for oral absorption on BCS II drugs in SNEDDS

Purpose

The objective of this study was to compare the in vitro Fick’s first law, in vitro lipolysis, and in vivo rat assays for oral absorption of Biopharmaceutical Classification Systems Class II (BCS II) drugs in self-nanoemulsifying drug delivery system (SNEDDS), and studied drugs and oils properties effects on the absorption.

Methods

The transport abilities of griseofulvin (GRI), phenytoin (PHE), indomethacin (IND), and ketoprofen (KET) in saturated water solutions and SNEDDS were investigated using the in vitro Madin-Darby canine kidney cell model. GRI and cinnarizine (CIN) in medium-chain triglycerides (MCT)-SNEDDS and long-chain triglycerides (LCT)-SNEDDS were administered in the in vivo SD rat and in vitro lipolysis models to compare the oral absorption and the distribution behaviors in GIT and build an in vitro-in vivo correlation (IVIVC).

Results

In the cell model, the solubility of GRI, PHE, IND, and KET increased 6–8 fold by SNEDDS, but their permeability were only 18%, 4%, 8%, and 33% of those of their saturated water solutions, respectively. However, in vivo absorption of GRI-SNEDDS was twice that of the GRI suspension and those of CIN-SNEDDS were 15–21 fold those of the CIN suspension. In the lipolysis model, the GRI% in aqueous and pellet phases of MCT were similar to that in LCT. In contrast, the CIN% in the aqueous and pellet phases were decreased but that of the lipid phase increased. In addition, an IVIVC was found between the CIN% in the lipid phase and in vivo relative oral bioavailability (F_r).

Conclusion

The in vitro cell model was still a suitable tool to study drug properties effects on biofilm transport and SNEDDS absorption mechanisms. The in vitro lipolysis model provided superior oral absorption simulation of SNEDDS and helped to build correlation with in vivo rats. The oral drug absorption was affected by drug and oil properties in SNEDDS.

Multicomponent self nano emulsifying delivery systems of resveratrol with enhanced pharmacokinetics profile

Resveratrol is a drug with high potential for clinical application based on experimental models. Though, resveratrol translation to clinical use has not been successful yet due to its poor pharmacokinetics, related to poor solubility and fast metabolism. The use of drug delivery systems, namely self-emulsifying drug delivery systems (SEDDS), may be a viable strategy to overcome the poor in vivo performance of resveratrol. In this work, a rational development of two different ternary SEDDS was conducted. Experimental data showed that quantitative variations on SEDDS composition impacted dispersion and robustness to dilution of SEDDS, as well as loading capacity and droplet size. Formulations composed of Lauroglycol® 90/Labrasol®/Capryol® PGMC (12.5/75.0/12.5) (Lau/Lab/Cap) and Tween® 80/Transcutol®/Imwitor® 742 (33.3/33.3/33.3) (T80/Trans/Imw) featured improved performance and were selected for further studies. T80/Trans/Imw formulation yield faster emulsification and originated smaller droplet size, with lower cumulative percentile of 90% of particles (D₉₀) (below 200 nm), as compared to the than Lau/Lab/Cap formulation. Higher resveratrol permeation rate was observed in Caco-2 cell monolayer permeability studies for both formulations as compared to the free drug. Reduction of the metabolization and/or efflux of resveratrol was also noticed in the case of SEDDs, as suggested by the increased recovery of total drug. Plasmatic drug concentrations in rats observed after oral gavage indicate that both formulations provided faster resveratrol absorption than free drug, resulting in shorter T_max values (30 min vs. 2 h). No statistically significant differences were observed for AUC_0-t values of both formulations and the free drug. Still, C_max for the Lau/Lab/Cap SEDDs formulation was 2-fold higher than for the free drug. These findings suggest that SEDDS can increase resveratrol solubility and reduce its metabolization, resulting in an overall improvement of its oral pharmacokinetics profile.

Successful development of oral SEDDS: screening of excipients from the industrial point of view

Oral administration is the most accepted and favored route as various side effects such as fear, pain and risk of infections can be avoided resulting in a comparatively high patient compliance. However, from the industrial point of view the development of oral delivery systems is still challenging as various drugs are poorly soluble as well as slightly permeable leading to low bioavailability. As self-emulsifying drug delivery systems are able to incorporate both hydrophobic and hydrophilic drugs, these carrier systems have received more and more attention within the last years. Based on the broad range of currently available excipients, this review provides a kind of guideline for the selection of excipients useful to improve bioavailability of the drug on the one hand. As the regulatory status of potential excipients are highly important to introduce the formulation on the market, the review is focused on the other hand on excipients listed in the IIG database of the FDA by taking their corresponding maximum concentration into account. Furthermore, the issue of oral sensation and taste masking is discussed useful for the development of intraoral SEDDS.

Development and Characterization of a Self-Nanoemulsifying Drug Delivery System Comprised of Rice Bran Oil for Poorly Soluble Drugs

Poor aqueous solubility and low bioavailability are limiting factors in the oral delivery of lipophilic drugs. In a formulation approach to overcome these limitations, rice bran (RB) oil was evaluated as drug carrier in the development of self-nanoemulsifying drug delivery systems (SNEDDS). The performance of RB in formulations incorporating Kolliphor RH40 or Kolliphor EL as surfactants and Transcutol HP as cosolvent was compared to a common oil vehicle, corn oil (CO). Serial dilutions of the preconcentrates were performed in various media [distilled water and simulated intestinal fluids mimicking fasted state (FaSSIF) and fed state (FeSSIF)] and at different dilution ratios to simulate the in vivo droplets' behavior. The developed SNEDDS were assessed by means of phase separation, droplet size, polydispersity index, and ζ-potential. Complex ternary diagrams were constructed to identify compositions exhibiting monophasic behavior, droplet size < 100 nm, and polydispersity index (PDI) < 0.25. Multifactor analysis and response surface areas intended to determine the factors significantly affecting droplet size. The oil capacity to accommodate lipophilic drugs was assessed via fluorescence spectroscopy based on the solvatochromic behavior of Nile Red. Solubility studies were performed to prepare fenofibrate- and itraconazole-loaded SNEDDS and assess their droplet size, whereas dissolution experiments were conducted in simulated intestinal fluids. Caco-2 cell viability studies confirmed the safety of the SNEDDS formulations at 1:100 and 1:1000 dilutions after cell exposure in culture for 4 h. The obtained results showed similar performance between RB and CO supporting the potential of RB as oil vehicle for the effective oral delivery of lipophilic compounds.

Dipeptides as co-formers in co-amorphous systems

Drug-amino acid co-amorphous systems have become increasingly well-investigated systems to improve dissolution rate of poorly water-soluble drugs. In this study, dipeptides were investigated as co-formers for co-amorphous systems based on the hypothesis that dipeptides might combine the inherent properties of the two included amino acids. Co-amorphization of the model drug mebendazole was investigated with five dipeptides, tryptophan-phenylalanine, phenylalanine-tryptophan, aspartic acid-tyrosine, histidine-glycine and proline-tryptophan. The dipeptides were chosen to investigate whether the side chains (nonpolar, polar, basic and acidic), and the sequence of amino acids (tryptophan-phenylalanine versus phenylalanine-tryptophan) have an influence on the performance of dipeptides as co-formers. All mebendazole-dipeptide systems became amorphous after ball milling for only 30 min, while this generally was not the case for the single amino acids or physical mixtures of the amino acids forming the dipeptides. Dissolution studies showed that the dissolution rate of mebendazole from most co-amorphous systems was increased significantly compared to crystalline and amorphous mebendazole. However, no clear trend for the drug dissolution enhancement was observed within the different co-amorphous drug-dipeptide systems. The stability study revealed that co-amorphous mebendazole-dipeptide systems showed higher physical stability compared to amorphous mebendazole. In conclusion, dipeptides are shown to be promising co-formers for co-amorphous systems.

Self-assembly and directed assembly of lipid nanocarriers for prevention of liver fibrosis in obese rats: a comparison with the therapy of bariatric surgery

Aim: Whether the obesity prevention by chemicals or surgeries in already obese patients is the better choice remains controversial. We aimed to compare the effect of orally silibinin-loaded nanocarriers and Roux-en-Y gastric bypass surgery on hepatic fibrosis in high-fat feeding-induced obese rats. Methodology: The developed nanocarriers included self-emulsifying drug delivery system (SNEDDS) and nanostructured lipid carriers (NLC). Results: A significant decrease in collagen production and lipid droplet formation was observed upon nanosystem and bariatric surgery than the rats treated with silibinin control suspension. Stage 3 fibrosis was present in 33% of the obese rats. This percentage could be minimized to 0% by SNEDDS and NLC. Following oral administration, SNEDDS and NLC resulted in 3.5- and 2.9-fold increase, respectively, in bioavailability compared with the reference suspension. Conclusion: Nanomedicine prevention provided a comparable efficiency to ameliorate liver steatosis as Roux-en-Y gastric bypass due to the improvement of silibinin dissolution and gastrointestinal permeation.

Self-nanoemulsifying drug-delivery systems improve oral absorption and antischistosomal activity of epiisopiloturine

Aim: To develop a self-nanoemulsifying drug-delivery system (SNEDDS) able to improve oral absorption of epiisopiloturine (EPI), and test the antischistosomal activity in a mice model. Results: SNEDDS had a nanoscopic size and was able to enhance EPI bioavailability after oral administration, and SNEDDS-EPI (40 mg.kg-1) improved the in vivo antischistosomal activity of EPI, demonstrating that SNEDDS was able to improve the pharmacokinetics of EPI, and to maintain the pharmacodynamic activity against Schistosoma mansoni in vivo. Conclusion: Taken together, these results indicate that SNEDDS-EPI is efficient in reducing worm burden in comparison to treatment with the free version of EPI.

[Formula: see text]

The Effect of Piperine Pro-Nano Lipospheres on Direct Intestinal Phase II Metabolism: The Raloxifene Paradigm of Enhanced Oral Bioavailability

Phase II biotransformation reactions have been gaining more attention due to their acknowledged significance in drug bioavailability, drug development, and drug-drug interactions. However, the predominant role of phase I metabolism has always overshadowed phase II metabolism, resulting in insufficient data regarding its mechanisms. In this paper, we investigate the effect of an advanced lipid based formulation on the phase II metabolism process of glucuronidation, occuring in the enterocytes monolayer. The investigated formulation is a self-emulsifying drug delivery system, termed pro-nano lipospheres, which contains the natural absorption enhancer piperine. To evaluate the effect of this formulation on direct glucuronidation we chose the model molecule raloxifene. First, glucuronidation is the main clearance pathway of this compound without involvement of preceding mechanisms. Second, raloxifene's extensive glucuronidation site is primarily at the intestine. Raloxifene's oral bioavailability was determined in a series of pharmacokinetic experiments using the freely moving rat model. In order to test the effect of the formulation on the relevant UGT enzymes reported in the clinic, we used the in vitro method of UGT-Glo Assay. Coadministration of raloxifene and piperine pro-nano lipospheres to rats resulted in a 2-fold increase in the relative oral bioavailability of raloxifene. However, coadministration of raloxifene with blank pro-nano lipospheres had no effect on its oral bioavailability. In contrast to the difference found in vivo between the two vehicles, both formulations extended an inhibitory effect on UGT enzymes in vitro. Ultimately, these findings prove the ability of the formulation to diminish intestinal direct phase II metabolism which serves as an absorption obstacle for many of today's marketed drugs. Pro-nano lipospheres is a formulation that serves as a platform for the simultaneous delivery of the absorption enhancer and a required drug. The discrepancy found between the in vivo and in vitro models demonstrates that the in vitro method may not be sensitive enough to distinguish the difference between the formulations.

Anticancer Efficacy of Self-Nanoemulsifying Drug Delivery System of Sunitinib Malate

Sunitinib malate (SM) is reported as a weakly soluble drug in water due to its poor dissolution rate and oral bioavailability. Hence, in the current study, various "self-nanoemulsifying drug delivery systems (SNEDDS)" of SM were prepared, characterized and evaluated for the enhancement of its in vitro dissolution rate and anticancer efficacy. On the basis of solubilization potential of SM in various excipients, "Lauroglycol-90 (oil), Triton-X100 (surfactant) and Transcutol-P (cosurfactant)" were selected for the preparation of SM SNEDDS. SM-loaded SNEDDS were developed by spontaneous emulsification method, characterized and evaluated for "thermodynamic stability, self-nanoemulsification efficiency, droplet size, polydispersity index (PDI), zeta potential (ZP), surface morphology, refractive index (RI), the percent of transmittance (% T) and drug release profile." In vitro dissolution rate of SM was significantly enhanced from an optimized SNEDDS in comparison with SM suspension. The optimized SNEDDS of SM with droplet size of 42.3 nm, PDI value of 0.174, ZP value of -36.4 mV, RI value of 1.339, % T value of 97.3%, and drug release profile of 95.4% (after 24 h via dialysis membrane) was selected for in vitro anticancer efficacy in human colon cancer cells (HT-29) by MTT assay. MTT assay indicated significant anticancer efficacy of optimized SM SNEDDS against HT-29 cells in comparison with free SM. The results of this study showed the great potential of SNEDDS in the enhancement of in vitro dissolution rate and anticancer efficacy of poorly soluble drug such as SM.

Nanotechnology: Revolutionizing the Science of Drug Delivery

Growing interest in the field of nanotechnology has led to its emergence in the field of medicine too. Nanomedicines encompass the various medical tools, diagnostic agents and the drug delivery vehicles being evolved with the advancements in the aura of nanotechnology. This review emphasizes on providing a cursory literature on the past events that led to the procession of nanomedicines, various novel drug delivery systems describing their structural features along with the pros and cons associated with them and the nanodrugs that made a move to the clinical practice. It also focuses on the need of the novel drug delivery systems and the challenges faced by the conventional drug delivery systems.

Measuring the emulsification dynamics and stability of self-emulsifying drug delivery systems

Self-emulsifying drug delivery systems (SEDDS) are one of the most promising technologies in the drug delivery field, particularly for addressing solubility and bioavailability issues of drugs. The development of these drug carriers excessively relies in visual observations and indirect determinations. The present manuscript intended to describe a method able to measure the emulsification of SEDDS, both micro and nano-emulsions, able to measure the droplet size and to evaluate the physical stability of these formulations. Additionally, a new process to evaluate the physical stability of SEDDS after emulsification was also proposed, based on a cycle of mechanical stress followed by a resting period. The use of a multiparameter continuous evaluation during the emulsification process and stability was of upmost value to understand SEDDS emulsification process. Based on this method, SEDDS were classified as fast and slow emulsifiers. Moreover, emulsification process and stabilization of emulsion was subject of several considerations regarding the composition of SEDDS as major factor that affects stability to physical stress and the use of multicomponent with different properties to develop a stable and robust SEDDS formulation. Drug loading level is herein suggested to impact droplets size of SEDDS after dispersion and SEDDS stability to stress conditions. The proposed protocol allows an online measurement of SEDDS droplet size during emulsification and a rationale selection of excipients based on its emulsification and stabilization performance.

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.

PLGA nanoparticles for the oral delivery of nuciferine: preparation, physicochemical characterization and in vitro/in vivo studies

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89 ± 0.71 and 88.54 ± 7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83 ± 5.72 nm and negative charge of -22.73 ± 1.63 mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ∼77 ± 6.67% was released in simulating intestinal juice, while only about 45.95 ± 5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG2 cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.

Long-chain triglycerides-based self-nanoemulsifying oily formulations (SNEOFs) of darunavir with improved lymphatic targeting potential

The current studies entail systematic development of SNEOFs containing long-chain triglycerides for improving lymphatic targeting of darunavir for complete inhibition of HIV progression. As per QbD-oriented approach for formulation development, the QTPP was defined and CQAs were earmarked. Preformulation equilibrium solubility and phase diagram studies, and risk assessment through FMEA studies identified Lauroglycol 90, Tween 80 and Transcutol HP as the lipid, emulgent and cosolvent, respectively, for formulating SNEOFs of darunavir. Systematic optimisation of SNEOFs was conducted using IV-optimal mixture design, and the optimised formulation was chosen through numerical desirability function. Characterisation of optimised SNEOFs exhibited globule size of 50 nm,  >85% drug release within 15 min and >75% permeation within 45 min. In vivo lymph cannulation and in situ intestinal perfusion studies indicated significant improvement in the drug absorption parameters from SNEOFs via intestinal lymphatic pathways, owing primarily to the presence of long-chain triglycerides. Also, in vivo pharmacokinetic studies in rat corroborated significant improvement in rate and extent of drug absorption into plasma vis-à-vis pure drug. In a nutshell, these studies indicate significant improvement in the biopharmaceutical attributes of a robust and stable SNEOFs formulation of darunavir for holistic management of viral loads in lymph and blood.

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.

Hyperuricemia-Related Diseases and Xanthine Oxidoreductase (XOR) Inhibitors: An Overview

Uric acid is the final oxidation product of purine metabolism in humans. Xanthine oxidoreductase (XOR) catalyzes oxidative hydroxylation of hypoxanthine to xanthine to uric acid, accompanying the production of reactive oxygen species (ROS). Uric acid usually forms ions and salts known as urates and acid urates in serum. Clinically, overproduction or under-excretion of uric acid results in the elevated level of serum uric acid (SUA), termed hyperuricemia, which has long been established as the major etiologic factor in gout. Accordingly, urate-lowering drugs such as allopurinol, an XOR-inhibitor, are extensively used for the treatment of gout. In recent years, the prevalence of hyperuricemia has significantly increased and more clinical investigations have confirmed that hyperuricemia is an independent risk factor for cardiovascular disease, hypertension, diabetes, and many other diseases. Urate-lowering therapy may also play a critical role in the management of these diseases. However, current XOR-inhibitor drugs such as allopurinol and febuxostat may have significant adverse effects. Therefore, there has been great effort to develop new XOR-inhibitor drugs with less or no toxicity for the long-term treatment or prevention of these hyperuricemia-related diseases. In this review, we discuss the mechanism of uric acid homeostasis and alterations, updated prevalence, therapeutic outcomes, and molecular pathophysiology of hyperuricemia-related diseases. We also summarize current discoveries in the development of new XOR inhibitors.