Nanosuspension of efavirenz for improved oral bioavailability: formulation optimization,in vitro, in situandin vivoevaluation

Febuxostat ternary inclusion complex using SBE7-βCD in presence of a water-soluble polymer: physicochemical characterization, in vitro dissolution, and in vivo evaluation

Febuxostat (FBX), a potent xanthine oxidase inhibitor, is widely used as a blood uric acid-reducing agent and has recently shown a promising repurposing outcome as an anti-cancer. FBX is known for its poor water solubility, which is the main cause of its weak oral bioavailability. In a previous study, we developed a binary system complex between FBX and sulfobutylether-β-cyclodextrin (SBE7-βCD) with improved dissolution behavior. The aim of the current study was to investigate the effect of incorporating a water-soluble polymer with a binary system forming a ternary one, on further enhancement of FBX solubility and dissolution rate. In vivo oral bioavailability was also studied using LC-MS/MS chromatography. The polymer screening study revealed a marked increment in the solubility of FBX with SBE7-βCD in the presence of 5% w/v polyethylene glycol (PEG 6000). In vitro release profile showed a significant increase in the dissolution rate of FBX from FBX ternary complex (FTC). Oral in vivo bioavailability of prepared FTC showed more than threefold enhancement in Cmax value (17.05 ± 2.6 µg/mL) compared to pure FBX Cmax value (5.013 ± 0.417 µg/mL) with 257% rise in bioavailability. In conclusion, the association of water-soluble polymers with FBX and SBE7-βCD system could significantly improve therapeutic applications of the drug.

Quality-by-design based fabrication of febuxostat-loaded nanoemulsion: Statistical optimization, characterizations, permeability, and bioavailability studies

The present work deals with QbD-based development of FEB-loaded nanoemulsion (FEB-NE) in order to enhance bioavailability and permeability. In the beginning, the risk assessment was performed on different experimental variables using the Ishikawa diagram followed by FMEA study in order to find critical process parameter (CPP) and critical material attributes (CMAs). To build quality in nanoemulsion, the quality target product profiles (QTPP) and critical quality attributes (CQAs) were determined. The different batches of FEB-NE were produced by the microemulsification-probe sonication method. Effect of varying levels of independent variables such as oil concentration (X₁), S_mix concentration (X₃), and amplitude (X₃) on responses such as globule size (Y₁), zeta potential (Y₂), and entrapment efficiency (Y₃) were studied using Box-Behnken design (BDD). FEB-NE formulation was optimized using a graphical and numerical method. The optimized formulation concentrations and their responses (CQAs) were located as design space in an overlay plot. The spherical shapes of globules were visualized by surface morphology using AFM and TEM. In vitro dissolution study showed 93.32% drug release from the optimized FEB-NE formulation. The drug release mechanism followed by the formulation was the Higuchi-matrix kinetics with a regression coefficient of 0.9236 (R²). FEB-NE showed enhanced permeability using PAMPA (artificial non-cell membrane) and everted gut sac model method. The developed optimized FEB-NE exhibited the enhancement of bioavailability by 2.48 fold as compared to FEB-suspension using Wistar rats suggesting improvement of solubility of a lipophilic drug. The optimized batch remained stable for 90 days at 4 °C and 25 °C. Thus, QbD-based development of FEB-NE can be useful for a better perspective on a commercial scale.

Solid lipid nanoparticles cyclodextrin-decorated incorporated into gellan gum-based dry floating in situ delivery systems for controlled release of bioactive compounds of safflower (Carthamus tinctorius. L): A proof of concept study in biorelevant media

Safflower (Carthamus tinctorius L.) has been explored as a source of natural antioxidant. However, quercetin 7-O-beta-D-glucopyranoside and luteolin 7-O-beta-D-glucopyranoside, as its bioactive compounds, possessed poor aqueous solubility, limiting its efficacy. Here, we developed solid lipid nanoparticles (SLNs) decorated with hydroxypropyl beta-cyclodextrin (HPβCD) incorporated into dry floating gel in situ systems to control the release of both compounds. Using Geleol® as a lipid matrix, SLNs were <200 nm in size with >80 % of encapsulation efficiency. Importantly, following the decoration using HPβCD, the stability of SLNs in gastric environment was significantly improved. Furthermore, the solubility of both compounds was also enhanced. The incorporation of SLNs into gellan gum-based floating gel in situ provided desired flow and floating properties, with <30 s gelation time. The floating gel in situ system could control the release of bioactive compounds in FaSSGF (Fasted-State Simulated Gastric Fluid). Furthermore, to assess the effect of food intake on release behavior, we found that the formulation could show a sustained release pattern in FeSSGF (Fed-State Simulated Gastric Fluid) for 24 h after being released in FaSGGF for 2 h. This indicated that this combination approach could be a promising oral delivery for bioactive compounds in safflower.

The Impact of Process and Formulation Parameters on the Fabrication of Efavirenz Nanosuspension to Improve Drug Solubility and Dissolution

Background

Efavirenz nanosuspensions (EZ-NSs) were developed by the wet milling method as the most promising top-down nanosizing technique. Different process and formulation parameters were studied and optimized to produce appropriate EZ-NS in suitable conditions to enhance drug dissolution.

Methods

In the preliminary studies, various polymeric stabilizers, including Pluronic F68, sodium carboxymethylcellulose (CMC), hydroxypropyl methylcellulose (HPMC), and polyvinyl alcohol (PVA), as well as different sizes and weight of milling beads were used to prepare NSs. The effect of sodium lauryl sulfate (SLS) concentration on the NS properties was also evaluated. The influence of other formulation and process parameters, including polymer concentration, milling speed, and milling time, on the particle size and distribution of NSs were investigated using Box-Behnken design. The optimized freeze-dried nanosuspension was characterized by redispersibility, physicochemical properties, and stability.

Results

A combination of PVA and SLS was selected as steric and electrostatic stabilizers. The optimum EZ-NS displayed a uniform size distribution with a mean particle size and zeta potential of 254.4 nm and 21.1 mV, respectively. The solidified nanosuspension was well redispersed to the original nanoparticles. Significantly enhanced aqueous solubility (about 11-fold) and accelerated dissolution rate were observed for the optimized formulation. This could be attributed to the reduced particle size and partial amorphization of EZ during the preparation process, studied by X-ray diffraction. Accelerated studies confirmed the stability of the optimum freeze-dried formulation over the examined period of three months.

Conclusions

Optimization of different variables led to the formation of EZ-NSs with desired properties through wet milling in a very short time compared to the previous study and therefore reduced production costs. This formulation seems to be a suitable approach for solubility and dissolution enhancement of EZ and may have a great potential to improve the drug's oral bioavailability.

Quercetin-Loaded Mesoporous Silica Nanoparticle-Based Lyophilized Tablets for Enhanced Physicochemical Features and Dissolution Rate: Formulation, Optimization, and In Vitro Evaluation

Mesoporous silica nanoparticles (MSNPs) have been proposed as a potential approach for stabilizing the amorphous state of poorly water-soluble actives. This study aimed to improve the physiochemical characteristics of poorly water-soluble quercetin (QT) through a novel lyophilized formulation. Various parameters, including solvent polarity, QT-carrier mass ratio, and adsorption time, were studied to improve the loading of QT into MSNPs. The optimized loaded MSNPs were formulated into lyophilized tablets through a freeze-drying process using hydrophilic polyvinylpyrrolidone (PVP-K30) as a polymeric stabilizer and water-soluble sucrose as a cryoprotectant. The effect of PVP-K30 and sucrose on the particle size, disintegration time, friability, and time required to release 90% of QT were studied using 3² full factorial design. The optimized formula was characterized using different evaluating techniques; for instance, differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy, drug content, moisture content, and saturation solubility. The analysis proved that QT was consistently kept in the nanosize range with a narrow size distribution. The loaded silica nanoparticles and the optimized formulation are in an amorphous state devoid of any chemical interaction with the silica matrix or the lyophilization excipients. The optimized formula also featured low friability (less than 1%), fast disintegration (< 30 s), and a pronounced enhancement in saturation solubility and dissolution rate. Briefly, we established that the lyophilized MSNPs-based tablet would be a potential strategy for improving the rate of dissolution and, ultimately, the bioavailability of the poorly water-soluble QT.

How to Improve Solubility and Dissolution of Irbesartan by Fabricating Ternary Solid Dispersions: Optimization and In-Vitro Characterization

The purpose of this study is to improve the solubility and dissolution of a poorly soluble drug, Irbesartan, using solid dispersion techniques. For that purpose, different polymers such as Soluplus^®, Kollidon^® VA 64, Kolliphor^® P 407, and Polyinylpyrrolidone (PVP-K30) were used as carriers at different concentrations to prepare solid dispersion formulations through the solvent evaporation method. In order to prepare binary dispersion formulations, Soluplus^® and Kollidon^® VA 64 were used at drug: polymer ratios of 1:1, 1:2, 1:3, and 1:4 (w/w). Saturation solubility of the drug in the presence of used carriers was performed to investigate the quantitative increase in solubility. Dissolution studies were performed to explore the drug release behavior from the prepared dispersions. Additionally, the characterization of the prepared formulations was carried out by performing DSC, SEM, XRD, and FTIR studies. The results revealed that among binary systems, K₄ formulation (Drug: Kollidon^® VA 64 at ratio of 1:4 w/w) exhibited optimal performance in terms of increased solubility, drug release, and other investigated parameters. Furthermore, ternary dispersion formulations of the optimized binary formulation were prepared with two more polymers, Kolliphor^® P 407 and Polyvinylpyrrolidone (PVP-K30), at (Drug: Kollidon^® VA 64:ternary polymer) ratios of 1:4:1, 1:4:2, and 1:4:3 (w/w). The results showed that KPVP (TD₃) exhibited the highest increase in solubility, as well as dissolution rate, among ternary solid dispersion formulations. Results of solubility enhancement by ternary solid dispersion formulations were also supported by FTIR, DSC, XRD, and SEM analysis. Conclusively, it was found that the ternary solid dispersion-based systems were more effective compared to the binary combinations in improving solubility as well as dissolution of a poorly soluble drug (Irbesartan).

Nanoemulsions Containing Megestrol Acetate: Development, Characterization, and Stability Evaluation

Many active pharmaceutical ingredients (API) are poorly soluble in water and their low oral bioavailability is a major hindrance to their potential use. Megestrol acetate (MGA) is insoluble in water and its oral absorption is limited and considerably affected by food. Nanoemulsions (NEs) can be used as effective oral drug delivery systems where the hydrophobic API is loaded into the oil phase. In this study, MGA-loaded NEs were prepared based on the spontaneous emulsification technique. The effects of different excipients such as ethanol, Tween 80, Lipoid E80, and medium-chain triglyceride (MCT) on the NEs characterization were investigated. The experimental results indicated that optimum MGA-loaded NEs (F20) were nanometer-sized droplets (166.9 ± 3.0 nm) with negative zeta potential (-12.2 ± 1.1 mV). The effect of polyvinylpyrrolidone (PVP) on characteristic properties of F20 was also evaluated. On the selected NEs, in vitro dissolution tests and stability studies in various mediums and storage conditions were performed. The encapsulation efficiency of NEs were > 99%. The overall droplet size of F20 and PVP-2 (PVP-coated NEs) remained relatively stable as the pH changed from 1.2 to 6.8. It was determined that F20 and PVP-2 remained stable at 4°C until 12 weeks and had higher cytotoxicity on MCF-7 cells. To conclude, droplet size, surface charge, and stability are important properties for NEs to have sufficient effectiveness. In this study, alternative oral NEs of low-solubility drug MGA were developed considering the above features.

Assessment of Pharmacokinetic Parameters of Daidzein-Containing Nanosuspension and Nanoemulsion Formulations After Oral Administration to Rats

BACKGROUND AND OBJECTIVES

Daidzein has several biological effects such as antioxidation, anti-inflammation, chemoprevention, and anticancer effects. The aim of this study was to evaluate the impact of nano-formulations (nanoemulsion-NE and nanosuspension-NS) prepared to increase the oral bioavailability of daidzein, a poorly water-soluble isoflavone, on the pharmacokinetic parameters of daidzein in rats.

METHODS

A high-performance liquid chromatography-ultraviolet (HPLC-UV) method was successfully developed for daidzein analysis in rat plasma. The pharmacokinetics studies of the nano-sized formulations, compared to coarse daidzein suspension, were carried out in the rats by a single oral dose at 10 mg/kg (n = 6/group). Area under the plasma concentration-time curve from time zero to extrapolation to time infinity (AUC_0-∞), maximum plasma concentration (C_max), time to reach maximum plasma concentration (t_max), and elimination half life (t_1/2) values for coarse daidzein suspension, daidzein-NS, and daidzein-NE were estimated by a non-compartmental analysis.

RESULTS

The AUC values of daidzein-NE and daidzein-NS were approximately 2.62 and 2.65 times higher than that of coarse daidzein suspension, respectively (p < 0.05). Relative bioavailability (F_rel) (%) values of daidzein following oral administration of nanosuspension or nanoemulsion formulations were about 265.6% and 262.3%, respectively.

CONCLUSION

It revealed that nanoscale size is an important factor to overcome any dissolution rate barriers to oral bioavailability of the low water-soluble compound. Nanoemulsion and nanosuspension formulations are beneficial dosage forms to increase the oral bioavailability of Biopharmaceutical Classification System (BCS) Class II and Class IV compounds.

The quest for a better fight: How can nanomaterials address the current therapeutic and diagnostic obstacles in the fight against COVID-19?

The inexorable coronavirus disease 2019 (COVID-19) pandemic with around 226 million people diagnosed and approximately 4.6 million deaths, is still moving toward more frightening statistics, calling for the urgent need to explore solutions for the current challenges in therapeutic and diagnostic approaches. The challenges associated with existing therapeutics in COVID-19 include lack of in vivo stability, efficacy, and safety. Nanoparticles (NPs) can offer a handful of tools to tackle these problems by enabling efficacious and safe delivery of both virus- and host-directed therapeutics. Furthermore, they can enable maximized clinical outcome while eliminating the chance of resistance to therapy by tissue-targeting and concomitant delivery of multiple therapeutics. The promising application of NPs as vaccine platforms is reflected by the major advances in developing novel COVID-19 vaccines. Two of the most critical COVID-19 vaccines are mRNA-based vaccines delivered via NPs, making them the first FDA-approved mRNA vaccines. Besides, NPs have been deployed as simple, rapid, and precise tools for point of care disease diagnosis. Not enough said NPs can also be exploited in novel ways to expedite the drug discovery process. In light of the above, this review discusses how NPs can overcome the hurdles associated with therapeutic and diagnostic approaches against COVID-19.

Best practices in current models mimicking drug permeability in the gastrointestinal tract - an UNGAP review

The absorption of orally administered drug products is a complex, dynamic process, dependent on a range of biopharmaceutical properties; notably the aqueous solubility of a molecule, stability within the gastrointestinal tract (GIT) and permeability. From a regulatory perspective, the concept of high intestinal permeability is intrinsically linked to the fraction of the oral dose absorbed. The relationship between permeability and the extent of absorption means that experimental models of permeability have regularly been used as a surrogate measure to estimate the fraction absorbed. Accurate assessment of a molecule's intestinal permeability is of critical importance during the pharmaceutical development process of oral drug products, and the current review provides a critique of in vivo, in vitro and ex vivo approaches. The usefulness of in silico models to predict drug permeability is also discussed and an overview of solvent systems used in permeability assessments is provided. Studies of drug absorption in humans are an indirect indicator of intestinal permeability, but in vitro and ex vivo tools provide initial screening approaches are important tools for direct assessment of permeability in drug development. Continued refinement of the accuracy of in silico approaches and their validation with human in vivo data will facilitate more efficient characterisation of permeability earlier in the drug development process and will provide useful inputs for integrated, end-to-end absorption modelling.

Efavirenz Loaded Mixed Polymeric Micelles: Formulation, Optimization, and In Vitro Characterization

Efavirenz (EFZ) is a biopharmaceutics classification system (BCS) Class-II, first-line antiretroviral (ARV) drug. However, its utility through the oral route is restricted by its poor solubility. The objective of this study was to formulate EFZ-loaded binary-mixed micelles as a potential carrier for oral administration of EFZ. Rubingh's regular solution theory was used to determine the interaction behavior of the two components (Cremophor RH 40 and Phospholipon 80H) and of the mixed micelles and synergistic behavior was confirmed. The mixed miceller system was formulated using solvent evaporation method and a 3² factorial design was used for the optimization of selected independent variables. Miceller systems were further characterized in terms of morphology, particle size, zeta potential, percent entrapment efficiency, and drug loading. Fourier transform infrared and differential scanning calorimetry measurements confirmed the entrapment of EFZ in the micelles. The optimized formulation presented desirable qualities viz., nanometric size (17.27 ± 0.079), high entrapment efficiency, and good colloidal stability. The prepared optimized micelles can be potential carriers for EFZ in ARV therapies.

Characterization, in vitro dissolution, and pharmacokinetics of different batches of efavirenz raw materials

OBJECTIVE

To perform the solid-state characterization and the in vitro-in vivo correlation (IVIVC) of three batches of efavirenz (EFV) active pharmaceutical ingredients.

SIGNIFICANCE

EFV is an effective anti-HIV drug. Due to the poor aqueous solubility, the rate and extent of EFV absorption deeply depend on its dissolution characteristics.

METHODS

Thermal analyses, x-ray diffraction, and particle size distribution were performed. The saturation solubility and dissolution profiles were assessed in 0.5% (w/v) sodium lauryl sulfate (SLS), fasted-state simulated intestinal fluid (FaSSIF), and fed-state simulated intestinal fluid (FeSSIF) using a flow-through cell. Each batch was orally administered to Wistar rats and the pharmacokinetic parameters were correlated with those obtained from in vitro dissolution.

RESULTS

All batches of EFV consisted polymorph I. EFV-A presented the lowest particle size distribution [d(v,0.5) = 197.8 µm; d(v,0.9) = 444.6 µm] followed by EFV-B [d(v,0.5) = 223.9 µm; d(v,0.9) = 481.1 µm], and EFV-C [d(v,0.5) = 240.8 µm; d(v,0.9) = 497.3 µm]. The saturated solubility in FaSSIF was 36% and 40% of that in FeSSIF and SLS, respectively. EFV-A presented the fastest rate and largest extension of dissolution than EFV-B and C (79.15%, 69.93% and 54.22%, respectively, as well as the highest maximum plasma concentration. Levels B, C, and multiple-C of IVIVC models were achieved.

CONCLUSION

The FaSSIF medium discriminated the dissolution profiles of EFV APIs. Small differences in particle size distribution had a significant impact on the biopharmaceutical parameters of EFV, suggesting that strict control of such parameter is an important aspect during API development and drug formulation.

Nanosuspensions of a poorly soluble investigational molecule ODM-106: Impact of milling bead diameter and stabilizer concentration

Aqueous solubility of a drug substance is an important attribute affecting oral bioavailability. Nanonization, particle size reduction to submicron level, is an elegant approach to improve drug solubility and dissolution by increasing the surface energy, which in turn necessitates the use of stabilizers. The purpose of this study was to develop a nanosuspension of a practically water-insoluble investigational molecule by nanomilling approach using wet media milling. A variety of polymeric and surface active excipients were tested for their wettability. A combination of hydroxypropyl methylcellulose and sodium lauryl sulfate (SLS) were selected as stabilizers on the bases of compatibility studies and efficient wettability behaviour in contact angle measurements (≈80˚). A factorial design set-up was used to study the effect of milling bead diameter and stabilizer concentration on the efficiency of particle size reduction. Nanonization outcome was different when milling beads of 0.5 mm and 1 mm diameter were used at different concentrations of the stabilizers, which demonstrated the complex nature of the whole system. Storage of the nanosuspensions under different temperature conditions resulted only in minor changes of the particle size fractions.

Development of Pediatric Orodispersible Tablets Based on Efavirenz as a New Therapeutic Alternative

BACKGROUND

Efavirenz is the most used medication in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The limited number of pediatric antiretroviral formulations approved by regulatory agencies is the most significant obstacle to adequate and efficient pharmacotherapy for this group of patients. The efavirenz has excellent therapeutic potential, but has low aqueous solubility/bioavailability.

METHODS

To minimize these limitations, multicomponent systems with β-cyclodextrin and polyvinylpyrrolidone K-30 were obtained. Due to the limited number of pediatric antiretroviral formulations, the development of a pediatric orodispersible tablet is an alternative that is thought easy to administer, since it disintegrates rapidly in the oral cavity. The multicomponent systems were obtained by the method of kneading and characterized by solubility test, X-ray diffraction, differential scanning calorimetry and infrared absorption spectroscopy by Fourier transform. The orodispersible tablets were prepared by direct compression. The quality control of hardness, friability, disintegration, and dissolution was performed. The influence of the components of the formulation on the characteristics of the tablets was evaluated through a 22 factorial design added with three central points, to compare the effect of the dependent variables on the responses.

RESULTS

An increase in drug solubility was observed, with a decrease in crystallinity. Besides that, an excellent dissolution profile presented with more than 83% of the drug's content dissolved in less than 15 minutes. Satisfactory disintegration time and friability were observed.

CONCLUSION

It was observed that reduced concentrations of mannitol decreased the hardness and disintegration time of the formulations. The orodispersible tablet composed of efavirenz: β- cyclodextrin: polyvinylpyrrolidone, favors greater absorption and bioavailability. It has several advantages for pediatric patients, as the dosage form disintegrates quickly in the mouth and does not require water for administration, thereby improving patient compliance with the treatment.

Formulation and optimization of liquisolid compact for enhancing dissolution properties of efavirenz by using DoE approach

Efavirenz displays low and variable bioavailability because of its poor aqueous solubility and high log P-value. The present investigation was aimed to improve the dissolution profile of efavirenz by using a simple, scalable and cost-effective technique of liquisolid compact. The drug was dissolved in Trancutol-HP for preparing the liquid medicament which was subsequently mixed with carrier and coating material to make free-flowing and compressible powder. 3² full factorial design was used to optimize the formulation in which the Neusilin US2/Corn starch ratios and carrier/coating material ratio were selected as independent variables. The results of in-vitro dissolution test proved that liquisolid compacts have significantly higher dissolution rate than tablets containing pure drug. Results of DSC and XRD studies suggested that the high dissolution of the drug from the liquisolid compacts was possibly because of the drug either being in an amorphous state or being molecularly dispersed within the internal matrix of compacts.

Rutin nanosuspension for potential management of osteoporosis: effect of particle size reduction on oral bioavailability, in vitro and in vivo activity

Clinical significance of Rutin (RUT) is limited by poor dissolution rate and low oral bioavailability. The study was designed to improve the physicochemical and therapeutic potential of the drug by formulating nanosuspension (NS) for osteoporosis. Rutin nanosuspension (RUT-NS) was prepared after screening a range of stabilizers and their combinations at a different concentration by antisolvent precipitation technique. Effect of precipitation on crystallinity (differential scanning calorimetry DSC, X-ray diffraction studies XRD), morphology (scanning electron microscopy, SEM) and chemical interaction (attenuated total reflectance fourier-transform infrared spectroscopy ATR-FTIR) were studied through biophysical techniques. An optimized nanosuspension exhibited a minimum particle size of 122.85 ± 5.02 nm with higher dissolution of RUT-NS (87. 63 ± 2.29%) as compared to pure drug (39.77 ± 2.8 6%). The enhanced intestine absorption and apparent permeability were achieved due to the improved particle size, surface area and dissolution. RUT-NS displayed greater (3 folds) AUC_0-24 h than pure drug. In vitro assays with RUT-NS depicted an increased cell proliferation, antioxidant (ROS) activity and osteocalcin production in MG-63 osteoblast cells. The augmented biochemical in vivo biomarkers and bone quality proved the protective effect of RUT-NS. The results supported RUT-NS as a potential therapy for maintaining bone health.

Organogel Nanoparticles as a New Way to Improve Oral Bioavailability of Poorly Soluble Compounds

PURPOSE

The aim of the study was to evaluate organogel nanoparticles as a lipophilic vehicle to increase the oral bioavailability of poorly soluble compounds. Efavirenz (EFV), a Biopharmaceutical Classification System (BCS) Class II, was used as drug model.

METHODS

Organogel nanoparticles loaded with EFV were formulated with sunflower oil, 12-hydroxystearic acid (HSA) and polyvinyl alcohol (PVA). Various parameters have been investigated in the current study such as (i) the release profile of organogel assessed by USP 4 cell flow dialysis, (ii) the impact of organogel on intestinal absorption, using Caco-2 cells as in vitro model and jejunum segments as ex vivo assay and (iii) the bioavailability of organogel following oral pharmacokinetic study.

RESULTS

250-300 nm spherical particles with a final concentration of 4.75 mg/mL drug loading were obtained, corresponding to a thousand fold increase in EFV solubility, combined to a very high encapsulation efficiency (>99.8%). Due to rapid diffusion, drug was immediately released from the nanoparticles. The biopharmaceutical evaluation on ex vivo jejunum segments demonstrated an increased absorption of EFV from organogel nanoparticles compare to a native EFV suspension. In vitro assays combining Caco-2 cell cultures with TEM and confocal microscopy demonstrated passive diffusion, while paracellular integrity and endocytosis activity remain expelled. Oral pharmacokinetics of EFV organogel nanoparticles improve oral bioavailability (F_r: 249%) and quick absorption compared to EFV suspension.

CONCLUSION

Organogel nanoparticles increase the bioavailability of BCS Class II drugs. The main phenomena is simply oil transfer from the gelled particles through the cell membrane.

Nanoformulation strategies for improving intestinal permeability of drugs: A more precise look at permeability assessment methods and pharmacokinetic properties changes

The therapeutic efficacy of orally administered drugs is often restricted by their inherent limited oral bioavailability. Low water solubility, limited permeability through the intestinal barrier, instability in harsh environment of the gastrointestinal (GI) tract and being substrate of the efflux pumps and the cytochrome P450 (CYP) can impair oral drug bioavailability resulting in erratic and variable plasma drug profile. As more drugs with low membrane permeability are developed, new interest is growing to enhance their intestinal permeability and bioavailability. A wide variety of nanosystems have been developed to improve drug transport and absorption. Sufficient evidence exists to suggest that nanoparticles are able to increase the transepithelial transport of drug molecules. However, key questions remained unanswered. What types of nanoparticles are more efficient? What are preclinical (or clinical) achievements of each type of nanoformulation in terms of pharmacokinetic (PK) parameters? Addressing this issue in this paper, we have reviewed the current literature regarding permeability enhancement, permeability assessment methods and changes in PK parameters following administration of various nanoformulations. Although permeability enhancement by various nanoformulations holds great promise for oral drug delivery, many challenges still need to be addressed before development of more clinically successful nanoproducts.

Nanomaterials Designed for Antiviral Drug Delivery Transport across Biological Barriers

Viral infections are a major global health problem, representing a significant cause of mortality with an unfavorable continuously amplified socio-economic impact. The increased drug resistance and constant viral replication have been the trigger for important studies regarding the use of nanotechnology in antiviral therapies. Nanomaterials offer unique physico-chemical properties that have linked benefits for drug delivery as ideal tools for viral treatment. Currently, different types of nanomaterials namely nanoparticles, liposomes, nanospheres, nanogels, nanosuspensions and nanoemulsions were studied either in vitro or in vivo for drug delivery of antiviral agents with prospects to be translated in clinical practice. This review highlights the drug delivery nanosystems incorporating the major antiviral classes and their transport across specific barriers at cellular and intracellular level. Important reflections on nanomedicines currently approved or undergoing investigations for the treatment of viral infections are also discussed. Finally, the authors present an overview on the requirements for the design of antiviral nanotherapeutics.

Fabrication of Fine Puerarin Nanocrystals by Box-Behnken Design to Enhance Intestinal Absorption

Puerarin is widely used as a therapeutic agent to cardiovascular diseases in clinics in China through intravenous administration, which could elicit adverse drug reactions caused by cosolvents, hindering its application in clinics. Therefore, the development of oral dosage is urgently needed. In our previous studies, we proved that the bioavailability of puerarin increased as particle sizes of nanocrystals decreased; however, we have not optimized the best process parameters for nanocrystals. In this study, we aim to fabricate fine nanocrystals (with smallest particle size) by Box-Behnken design and study the intestinal permeability of puerarin and its nanocrystals via employing everted gut sac model and in situ perfusion model. The results showed that the Box-Behnken design could be used to optimize the producing parameters of puerarin nanocrystals, and the particle sizes of fine nanocrystals were about 20 nm. Results of everted gut sacs showed that the polyvinylpyrrolidone (PVP) and verapamil had no influence on the absorption of puerarin and nanocrystals, and the nanocrystals could increase the P_app of puerarin for 2.2-, 2.9-, and 2.9-folds, respectively, in duodenum, jejunum, and ileum. Enhanced Ka and Peff were observed on the nanocrystal group, compared with puerarin, and PVP and verapamil had no influence on the absorption of nanocrystals, while the absorption of puerarin was influenced by P-gp efflux. Combining the results mentioned above, we can conclude that the Box-Behnken design benefits the optimization for preparation of nanocrystals, and the nanocrystals could enhance the intestinal absorption of puerarin by enhanced permeability and inhibited P-gp efflux.

Insight into the Formation of Glimepiride Nanocrystals by Wet Media Milling

Nanocrystal formation for the dissolution enhancement of glimepiride was attempted by wet media milling. Different stabilizers were tested and the obtained nanosuspensions were solidified by spray drying in presence of mannitol, and characterized regarding their redispersibility by dynamic light scattering, physicochemical properties by differential scanning calorimetry (DSC), FT-IR spectroscopy, powder X-ray diffraction (PXRD), and scanning electron microcopy (SEM), as well as dissolution rate. Lattice energy frameworks combined with topology analysis were used in order to gain insight into the mechanisms of particle fracture. It was found that nanosuspensions with narrow size distribution can be obtained in presence of poloxamer 188, HPC-SL and Pharmacoat^® 603 stabilizers, with poloxamer giving poor redispersibility due to melting and sticking of nanocrystals during spray drying. DSC and FT-IR studies showed that glimepiride does not undergo polymorphic transformations during processing, and that the milling process induces changes in the hydrogen bonding patterns of glimepiride crystals. Lattice energy framework and topology analysis revealed the existence of a possible slip plane on the (101) surface, which was experimentally verified by PXRD analysis. Dissolution testing proved the superior performance of nanocrystals, and emphasized the important influence of the stabilizer on the dissolution rate of the nanocrystals.

Recent Advances in Drug Delivery Strategies for Improved Therapeutic Efficacy of Efavirenz

BACKGROUND

Efavirenz, an anti-HIV agent, has a noticeable place in the HAART regimen for the treatment and maintenance therapy of AIDS. However, its poor water solubility accounts for hindered absorption and bio-distribution upon administration. This results in its low and variable bioavailability. To circumvent these limitations, various novel formulations of Efavirenz have been investigated in order to mitigate its drawbacks and draw out its maximum therapeutic effect.

METHODS

Numerous formulations explored to overcome the drawbacks of Efavirenz include modified/ controlled-release tablets, solid dispersions, polymeric nanoparticles, dendrimers, surface-engineered nanoparticles and various other nanoformulations. Moreover, combinatorial formulations of Efavirenz with other Anti-HIV drugs have also been reported to overcome the problem of Drug-Resistance.

RESULTS

The nanoformulation based strategies, owing to their ability to provide controlled release profile and targeted drug delivery were found to augment bioavailability, therapeutic efficacy and reduce the side effects of the Efavirenz.

CONCLUSION

This review pivots around the challenges and recent advances in the delivery of Efavirenz with particular emphasis on novel formulations including its patents.

Bioavailability Enhancement of Poorly Soluble Drugs: The Holy Grail in Pharma Industry

Background:

Bioavailability, one of the prime pharmacokinetic properties of a drug, is defined as the fraction of an administered dose of unchanged drug that reaches the systemic circulation and is used to describe the systemic availability of a drug. Bioavailability assessment is imperative in order to demonstrate whether the drug attains the desirable systemic exposure for effective therapy. In recent years, bioavailability has become the subject of importance in drug discovery and development studies.

Methods:

A systematic literature review in the field of bioavailability and the approaches towards its enhancement have been comprehensively done, purely focusing upon recent papers. The data mining was performed using databases like PubMed, Science Direct and general Google searches and the collected data was exhaustively studied and summarized in a generalized manner.

Results:

The main prospect of this review was to generate a comprehensive one-stop summary of the numerous available approaches and their pharmaceutical applications in improving the stability concerns, physicochemical and mechanical properties of the poorly water-soluble drugs which directly or indirectly augment their bioavailability.

Conclusion:

The use of novel methods, including but not limited to, nano-based formulations, bio-enhancers, solid dispersions, lipid-and polymer-based formulations which provide a wide range of applications not only increases the solubility and permeability of the poorly bioavailable drugs but also improves their stability, and targeting efficacy. Although, these methods have drastically changed the pharmaceutical industry demand for the newer potential methods with better outcomes in the field of pharmaceutical science to formulate various dosage forms with adequate systemic availability and improved patient compliance, further research is required.

Preparation, optimisation, and in vitro-in vivo evaluation of febuxostat ternary solid dispersion

The research aimed to prepare febuxostat (FEB) solid dispersion through solvent evaporation. Optimised solid dispersion composed of FEB, polyvinylpyrrolidone (PVP K30) and poloxamer at a ratio of 1:3:3 was characterised. Powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated FEB was transformed from crystalline into the amorphous state in solid dispersion and scanning electron microscopy (SEM) revealed the morphology. Fourier transform infrared spectroscopy (FT-IR) suggested the interactions formed between FEB and polymers. A remarkable increase was observed of the optimised formulation in saturation solubility, dissolution studies (96.17 ± 0.79% in pH 6.0), and bioavailability (C_max 18.25 ± 2.44 vs. 7.72 ± 0.48 μg/mL and AUC_0-∞ 53.62 ± 7.63 vs. 34.76 ± 2.45 μg·h/mL). Besides, the FEB solid dispersion showed great stability after 90 days storage. Thus, the present study supports the rationality of PVP K30 and poloxamer188 as co-carriers for the preparation of FEB solid dispersion.

Design Space and QbD Approach for Production of Drug Nanocrystals by Wet Media Milling Techniques

Drug nanocrystals are nanosized solid drug particles, the most important application of which is the improvement of solubility properties of poorly soluble drug materials. Drug nanocrystals can be produced by many different techniques, but the mostly used are different kinds of media milling techniques; in milling, particle size of bulk sized drug material is decreased, with the aid of milling beads, to nanometer scale. Utilization of Quality by Design, QbD, approach in nanomilling improves the process-understanding of the system, and recently, the number of studies using the QbD approach in nanomilling has increased. In the QbD approach, the quality is built into the products and processes throughout the whole production chain. Definition of Critical Quality Attributes, CQAs, determines the targeted final product properties. CQAs are confirmed by setting Critical Process Parameters, CPPs, which include both process parameters but also input variables, like stabilizer amount or the solid state form of the drug. Finally, Design Space determines the limits in which CPPs should be in order to reach CQAs. This review discusses the milling process and process variables, CPPs, their impact on product properties, CQAs and challenges of the QbD approach in nanomilling studies.

Bioavailability Enhancement of Poorly Water-Soluble Drugs via Nanocomposites: Formulation⁻Processing Aspects and Challenges

Drug nanoparticles embedded in a dispersant matrix as a secondary phase, i.e., drug-laden nanocomposites, offer a versatile delivery platform for enhancing the dissolution rate and bioavailability of poorly water-soluble drugs. Drug nanoparticles are prepared by top-down, bottom-up, or combinative approaches in the form of nanosuspensions, which are subsequently dried to prepare drug-laden nanocomposites. In this comprehensive review paper, the term &ldquo;nanocomposites&rdquo; is used in a broad context to cover drug nanoparticle-laden intermediate products in the form of powders, cakes, and extrudates, which can be incorporated into final oral solid dosages via standard pharmaceutical unit operations, as well as drug nanoparticle-laden strip films. The objective of this paper is to review studies from 2012⁻2017 in the field of drug-laden nanocomposites. After a brief overview of the various approaches used for preparing drug nanoparticles, the review covers drying processes and dispersant formulations used for the production of drug-laden nanocomposites, as well as various characterization methods including quiescent and agitated redispersion tests. Traditional dispersants such as soluble polymers, surfactants, other water-soluble dispersants, and water-insoluble dispersants, as well as novel dispersants such as wet-milled superdisintegrants, are covered. They exhibit various functionalities such as drug nanoparticle stabilization, mitigation of aggregation, formation of nanocomposite matrix⁻film, wettability enhancement, and matrix erosion/disintegration. Major challenges such as nanoparticle aggregation and poor redispersibility that cause inferior dissolution performance of the drug-laden nanocomposites are highlighted. Literature data are analyzed in terms of usage frequency of various drying processes and dispersant classes. We provide some engineering considerations in comparing drying processes, which could account for some of the diverging trends in academia vs. industrial practice. Overall, this review provides rationale and guidance for drying process selection and robust nanocomposite formulation development, with insights into the roles of various classes of dispersants.

Mechanical activation of Efavirenz: the effects on the dissolution and inhibitory behavior

A poorly water-soluble drug (Efavirenz) was mechanically activated by ball-milling. The effect of the mechanical activation on the dissolution behavior and bioavailability was investigated revealing possible correlations with the grinding action, in terms of crystallinity, particle size and morphology.With proper selection of the grinding parameters the dissolution kinetics can be controlled, both in terms of dissolution velocity and as amount of dissolved drug. In vitro biological tests show that milling does not impair the ability of Efavirenz to inhibit HIV-1 infection (p value >0.05); the IC50 values of ground Efavirenz is indeed lower than values for the pristine micronized powder.

Optimization of formulation and process parameters for the production of carvedilol nanosuspension by wet media milling

The aim of this study is to develop nanosuspension of carvedilol (CRV) by wet media milling. Concentration of polymeric stabilizer (hydroxypropyl cellulose-HPC-SL), milling speed and size of milling beads were identified as critical formulation and process parameters and their effect on CRV particle size after 60 min of milling was assessed using a Box-Behnken experimental design. Optimized nanosuspension was solidified using spray drying and freeze drying and subjected to solid state characterization. Low stabilizer concentration (10%), low milling speed (300 rpm) with small milling beads (0.1 mm) were found as optimal milling conditions. Crystal lattice simulation identified potential slip plane within CRV crystals, where fractures are the most likely to occur. Calculated mechanical properties of CRV crystal indicates that low energy stress is sufficient to initiate fracture, if applied in the correct direction, explaining the advantage of using smaller milling beads. Only spray dried nanosuspension redispersed to original nanoparticles, while particle agglomeration during freeze drying prevented sample redispersion. Wet milling and spray drying did not induce polymorphic transition of CRV, while there is indication of polymorphic transition during freeze drying, making spray drying as the preferred solidification method.

Efavirenz Dissolution Enhancement IV-Antisolvent Nanocrystallization by Sonication, Physical Stability, and Dissolution

Efavirenz is a fundamental drug in the HIV therapy; however, it has a low bioavailability due to low water solubility. Particle nanonization should enhance its dissolution and therefore its bioavailability. Nanocrystallization is a promising technique for preparing drug nanocrystals. A solution containing efavirenz (EFV) and methanol was added to an aqueous solution of particle stabilizers, under sonication. The adequate polymer stabilizer and its concentration and drug load were evaluated. Particle size and zeta potential of suspensions were measured. Nanosuspensions were freeze-dried and the resulting powder was characterized by some techniques, with special attention to dissolution. Particle size and zeta potential analysis showed that HMPC and PVP were the most suitable polymers. All samples prepared with these stabilizers had nanosized particles and proper zeta potential; however, sedimentation and particle growth were detected with Turbiscan™. Time-related destabilization occurred when the lowest polymer concentration of 20% was used. SEM analysis of the dried powder shows film formation for suspensions with 40% of polymer and particle aggregation in samples with less polymer. Dissolution profiles of samples were higher than EFV raw material, although the lower the polymer concentration, the higher the dissolution.

Enhancement of Bioavailability of Non-nucleoside Reverse Transciptase Inhibitor Using Nanosponges

Efavirenz is a non-nucleoside reverse transcriptase inhibitor which is chronically prescribed for HIV patients. However, it exhibits solubility-limited bioavailability. Aim of this work was to enhance the solubility and dissolution of the Biopharmaceutical Classification System (BCS) class II drug efavirenz, using beta-cyclodextrin-based nanosponges. Nanosponges have high drug loading capacity and are effective for solubility enhancement. Beta-cyclodextrin was crosslinked with carbonates in different ratios to prepare nanosponges. The nanosponges were loaded with efavirenz by solvent evaporation method and the nanosponge with higher drug loading capacity was selected for further studies. Binary and ternary complexes with EFA, NS, and PVP K30 were prepared and characterized by phase solubility, solution state interaction, saturation solubility, in vitro dissolution, and in vivo pharmacokinetics. Spectral analysis by Fourier transform infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and field emission scanning electron microscopy was performed. Results obtained from spectral characterization confirmed inclusion complexation. Stability constant for ternary complex was found to be 1997 lit/mole, which indicates stable complex formation. The saturation solubility was found to be 17-fold higher with ternary complex in distilled water and about 4-fold in simulated gastric fluid. In vitro dissolution was improved 3 folds with ternary complex. Ternary nanosponge complexes were found to have 2-fold increase in oral bioavailability of efavirenz as compared to plain drug.

Formulation of dried lignans nanosuspension with high redispersibility to enhance stability, dissolution, and oral bioavailability

Herpetospermum caudigerum lignans (HTL), one of the potential drugs with anti-hepatitis B virus and hepatoprotective effects, has limited clinical applications because of poor aqueous solubility and low bioavailability. Both herpetrione (HPE) and herpetin (HPN) are the most abundant ingredients in HTL and exhibit weak acidity. The purpose of the present study was to produce dried preparations of HTL (composed of HPE and HPN) nanosuspensions (HTL-NS) with high redispersibility using lyophilization technology. The HTL-NS was prepared by utilizing precipitation-combined homogenization technology based on acid-base neutralization reactions, and critical formulation and process parameters affecting the characteristics of HTL-NS were optimized. The resultant products were characterized by particle size analysis, SEM, XRD, stability, solubility, dissolution and in vivo bioavailability. HTL-NS showed near-spherical-shaped morphology and the size was 243 nm with a narrow PDI value of 0.187. The dried preparations with a relatively large particle size of 286 nm and a PDI of 0.215 were achieved by using 4% (W/V) mannitol as cryoprotectants, and had a better stability at 4 or 25 °C for 2 months, compared to HTL-NS. In the in vitro test, the dried preparations showed markedly increased solubility and dissolution velocity. Besides, in the in vivo evaluation, it exhibited significant increases in AUC_0-t, C_max,MRT and a decrease in T_max, compared to the raw drug. In conclusion, our results provide a basis for the development of a drug delivery system for poorly water-soluble ingredients with pH-dependent solubility.

Conjugation of Hot-Melt Extrusion with High-Pressure Homogenization: a Novel Method of Continuously Preparing Nanocrystal Solid Dispersions

Over the past few decades, nanocrystal formulations have evolved as promising drug delivery systems owing to their ability to enhance the bioavailability and maintain the stability of poorly water-soluble drugs. However, conventional methods of preparing nanocrystal formulations, such as spray drying and freeze drying, have some drawbacks including high cost, time and energy inefficiency, traces of residual solvent, and difficulties in continuous operation. Therefore, new techniques for the production of nanocrystal formulations are necessary. The main objective of this study was to introduce a new technique for the production of nanocrystal solid dispersions (NCSDs) by combining high-pressure homogenization (HPH) and hot-melt extrusion (HME). Efavirenz (EFZ), a Biopharmaceutics Classification System class II drug, which is used for the treatment of human immunodeficiency virus (HIV) type I, was selected as the model drug for this study. A nanosuspension (NS) was first prepared by HPH using sodium lauryl sulfate (SLS) and Kollidon® 30 as a stabilizer system. The NS was then mixed with Soluplus® in the extruder barrel, and the water was removed by evaporation. The decreased particle size and crystalline state of EFZ were confirmed by scanning electron microscopy, zeta particle size analysis, and differential scanning calorimetry. The increased dissolution rate was also determined. EFZ NCSD was found to be highly stable after storage for 6 months. In summary, the conjugation of HPH with HME technology was demonstrated to be a promising novel method for the production of NCSDs.

Cefdinir nanosuspension for improved oral bioavailability by media milling technique: formulation, characterization and in vitro-in vivo evaluations

Cefdinir (Cef) is an orally active Biopharmaceutics Classification System (BCS) class IV drug with incomplete absorption and low bioavailability (16-21%). The aim of this investigation was to develop nanosuspensions (NS) of Cef to improve its oral bioavailability. Cef NS were prepared by the media milling technique using zirconium oxide beads as the milling media. Cef NS were characterized by particle size, Scanning Electron Microscopy, Differential Scanning Calorimetry, X-Ray Diffraction pattern and evaluated for saturation solubility, in vitro release studies, ex vivo permeability studies and in vivo bioavailability studies. The particle size and zeta potential were found to be 224.2 ± 2.7 nm and -15.7 ± 1.9 mV, respectively. Saturation solubility of NS was found to be 1985.3 ± 10.2 µg/ml which was 5.64 times higher than pure drug (352.2 ± 6.5 µg/ml). The DSC thermograms and XRD patterns indicated that there was no interaction between drug and excipients and that the crystallinity of Cef remained unchanged after media milling process. Results of in vitro release studies and ex vivo permeation studies showed improved drug release of 88.2 1 ± 2.90 and 83.11 ± 2.14%, respectively, from NS after 24 h as compared to drug release of 54.09 ± 2.54 and 48.2 1 ± 1.27%, respectively, from the marketed suspension (Adcef). In vivo studies in rats demonstrated a 3-fold increase in oral bioavailability from the NS in comparison to marketed suspension. The results of this investigation conclusively show that the developed nanosuspension of Cef exhibited improved solubility, dissolution and permeation which led to a significant enhancement in its oral bioavailability.

Design of a novel type IV lipid-based delivery system for improved delivery of drugs with low partition coefficient

CONTEXT

The physicochemical properties of drugs such as partition coefficient play a major role in the development of lipid-based drug delivery systems. The major obstacle lies in encapsulation of a drug with low partition coefficient into these systems.

OBJECTIVE

The objective of this study was to design and optimize a novel lipid-based delivery system with higher loading, improved pharmacokinetics consequently enhancing the oral bioavailability of drugs with low partition coefficient like valsartan.

MATERIALS AND METHODS

The optimized formulation consists of Capryol 90, Cremophor RH 40, and Transcutol HP. Pseudo ternary phase diagrams were used to optimize the components and their concentrations in the formulation. Dissolution studies of the selected formulations were compared with plain drug and marketed product at three pH conditions (pH 1.2, 4.5 and 6.8). Pharmacokinetic parameters of optimized formulations were determined in Wistar rats and compared with that of plain drug.

RESULTS AND DISCUSSION

The optimized formulation with a mean particle size of 50 nm showed significant improvement (p < 0.05) in dissolution rate with pH independence compared to plain drug and marketed product. The in vivo studies in Wistar rats revealed about 2.30- and 1.68-fold increase in the oral bioavailability and Cmax of valsartan from lipid-based formulation compared to plain drug.

CONCLUSION

The engineered formulation strategy by type IV lipid-based formulations can be successfully exploited to improve the dissolution rate and oral deliverability of drugs like valsartan.

Custom fractional factorial designs to develop atorvastatin self-nanoemulsifying and nanosuspension delivery systems--enhancement of oral bioavailability

Poor water solubility of a drug is a major challenge in drug delivery research and a main cause for limited bioavailability and pharmacokinetic parameters. This work aims to utilize custom fractional factorial design to assess the development of self-nanoemulsifying drug delivery systems (SNEDDS) and solid nanosuspensions (NS) in order to enhance the oral delivery of atorvastatin (ATR). According to the design, 14 experimental runs of ATR SNEDDS were formulated utilizing the highly ATR solubilizing SNEDDS components: oleic acid, Tween 80, and propylene glycol. In addition, 12 runs of NS were formulated by the antisolvent precipitation–ultrasonication method. Optimized formulations of SNEDDS and solid NS, deduced from the design, were characterized. Optimized SNEDDS formula exhibited mean globule size of 73.5 nm, zeta potential magnitude of −24.1 mV, and 13.5 μs/cm of electrical conductivity. Optimized solid NS formula exhibited mean particle size of 260.3 nm, 7.4 mV of zeta potential, and 93.2% of yield percentage. Transmission electron microscopy showed SNEDDS droplets formula as discrete spheres. The solid NS morphology showed flaky nanoparticles with irregular shapes using scanning electron microscopy. The release behavior of the optimized SNEDDS formula showed 56.78% of cumulative ATR release after 10 minutes. Solid NS formula showed lower rate of release in the first 30 minutes. Bioavailability estimation in Wistar albino rats revealed an augmentation in ATR bioavailability, relative to ATR suspension and the commercial tablets, from optimized ATR SNEDDS and NS formulations by 193.81% and 155.31%, respectively. The findings of this work showed that the optimized nanocarriers enhance the oral delivery and pharmacokinetic profile of ATR.

Formulation and optimization of efavirenz nanosuspensions using the precipitation-ultrasonication technique for solubility enhancement

Efavirenz is a non-nucleoside reverse transcriptase inhibitor, and is classified as BCS Class II API. Its erratic oral absorption and poor bioavailability make it a potential candidate for being formulated as a nanosuspension. The objective of this study was to formulate efavirenz nanosuspensions employing the antisolvent precipitation-ultrasonication method, and to enhance its solubility by reducing particle size to the nanometer range. The effects of different process parameters were studied and optimized with respect to particle size and poly dispersity index (PDI). The optimized formulation was also subjected to lyophilization, to further increase the solubility and stability, and the technology is potentially suited to a range of poorly water-soluble compounds.

Phospholipid complex as an approach for bioavailability enhancement of echinacoside

CONTEXT

Echinacoside (ECH) has been shown to possess a multitude of pharmacological activities, however, oral administered ECH failed to fulfill its therapeutic potential due to poor absorption and low bioavailability. Thus, there is a pressing need to develop a new oral dosage form to enhance its intestinal absorption and improve bioavailability.

OBJECTIVE

The aim of this study was to formulate ECH into phospholipid complex (phytosome, PHY) to enhance intestinal absorption and oral bioavailability of ECH in vivo.

METHODS

The PHY was prepared by a solvent evaporation method and was characterized by differential scanning calorimetry (DSC) and infrared spectroscopy (IR), and then the physicochemical properties, intestinal absorption and bioavailability of the PHY were investigated.

RESULTS

Compared with the physical mixture (MIX) or ECH alone, the n-octanol/water partition coefficient (P) determination results showed that the lipophilicity of ECH was significantly enhanced by formation of PHY. Accordingly, the intestinal absorption rate (Ka) was improved to 2.82-fold and the effective permeability coefficient (Peff) increased to 3.39-fold. The concentrations of ECH in rat plasma at different times after oral administration of PHY were determined by HPLC. Pharmacokinetic parameters of the PHY in rats were Tmax = 1.500 h, Cmax = 3.170 mg/mL, AUC0-∞ = 9.375 mg/L h and AUC0-24 = 7.712 mg/L h, respectively.

CONCLUSIONS

Compared with ECH alone or the MIX group, the relative bioavailability of ECH was increased significantly after formulation into PHY (p < 0.05). This might be mainly due to an improvement of the absorption of PHY.

Preparation and in vitro evaluation of hydrophilic fenretinide nanoparticles

Fenretinide is an effective anti-cancer drug with high in vitro cytotoxicity and low in vivo systemic toxicity. In clinical trials, fenretinide has shown poor therapeutic efficacy following oral administration - attributed to its low bioavailability and solubility. The long term goal of this project is to develop a formulation for the oral delivery of fenretinide. The purpose of this part of the study was to prepare and characterize hydrophilic nanoparticle formulations of fenretinide. Three different ratios of polyvinyl pyrrolidone (PVP) to fenretinide were used, namely, 3:1, 4:1, and 5:1. Both drug and polymer were dissolved in a mixture of methanol and dichloromethane (2:23 v/v). Rotary evaporation was used to remove the solvents, and, following reconstitution with water, a high pressure homogenizer was used to form nanoparticles. The particle size and polydispersity index were measured before and after lyophilization. The formulations were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). The effectiveness of the formulations was assessed by release studies and Caco-2 cell permeability assays. As the PVP content increased, the recovered particle size following lyophilization became more consistent with the pre-lyophilization particle size, especially for those formulations with less lactose. The DSC scans of the formulations did not show any fenretinide melting endotherms, indicating that the drug was either present in an amorphous form in the formulation or that a solid solution of the drug in PVP had formed. For the release studies, the highest drug release among the formulations was 249.2±35.5ng/mL for the formulation with 4:1 polymer-to-drug. When the permeability of the formulations was evaluated in a Caco-2 cell model, the mean normalized flux for each treatment group was significantly higher (p<0.05) from the fenretinide control. The formulation containing 4:1 polymer-to-drug ratio and 6:5 lactose-to-formulation ratio emerged as the optimal choice for further evaluation as a potential oral delivery formulation for fenretinide.