Soluplus®/TPGS-based solid dispersions prepared by hot-melt extrusion equipped with twin-screw systems for enhancing oral bioavailability of valsartan

Self-micellizing solid dispersion of thymoquinone with enhanced biopharmaceutical and nephroprotective effects

The present study was designed to develop a self-micellizing solid dispersion (SMSD) containing Thymoquinone (TQM), a phytonutrient obtained from Nigella sativa seeds, aiming to improve its biopharmaceutical and nephroprotective functions. The apparent solubility of TQM in polymer solutions was used to choose an appropriate amphiphilic polymer that could be used to make an SMSD system. Based on the apparent solubility, Soluplus® was selected as an appropriate carrier, and mixing with TQM, SMSD-TQM with different loadings of TQM (5-15%) was made by solvent evaporation and freeze-drying techniques, respectively, and the formulations were optimized. The optimized SMSD-TQM was evaluated in terms of particle size distribution, morphology, release characteristics, pharmacokinetic behavior, and nephroprotective effects in a rat model of acute kidney injury. SMSD-TQM significantly improved the dissolution characteristics (97.8%) of TQM in water within 60 min. Oral administration of SMSD-TQM in rats exhibited a 4.9-fold higher systemic exposure than crystalline TQM. In a cisplatin-induced (6 mg/kg, i.p.) acute kidney-damaged rat model, oral SMSD-TQM (10 mg/kg) improved the nephroprotective effects of TQM based on the results of kidney biomarkers and histological abnormalities. These findings suggest that SMSD-TQM might be efficacious in enhancing the nephroprotective effect of TQM by overcoming biopharmaceutical limitations.

Genistein transfersome-embedded topical delivery system for skin melanoma treatment: in vitro and ex vivo evaluations

Skin melanoma is considered the most dangerous form of skin cancer due to its association with high risk of metastasis, high mortality rate and high resistance to different treatment options. Genistein is a natural isoflavonoid with known chemotherapeutic activity. Unfortunately, it has low bioavailability due to its poor aqueous solubility and excessive metabolism. In the current study, genistein was incorporated into transferosomal hydrogel to improve its bioavailability. The prepared transferosomal formulations were characterized regarding: particle size; polydispersity index; zeta potential; encapsulation efficiency; TEM; FTIR; DSC; XRD; in vitro drug release; viscosity; pH; ex vivo anti-tumor activity on 3D skin melanoma spheroids and 1-year stability study at different storage temperatures. The optimized formulation has high encapsulation efficiency with an excellent particle size that will facilitate its penetration through the skin. The transfersomes have a spherical shape with sustained drug release profile. The anti-tumor activity evaluation of genistein transfersome revealed that genistein is a potent chemotherapeutic agent with enhanced penetration ability through the melanoma spheroids when incorporated into transfersomes. Stability study results demonstrate the high physical and chemical stability of our formulations. All these outcomes provide evidence that our genistein transferosomal hydrogel is a promising treatment option for skin melanoma.

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

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

Amorphous Pterostilbene Delivery Systems Preparation-Innovative Approach to Preparation Optimization

The aim of our research was to improve the solubility and antioxidant activity of pterostilbene (PTR) by developing a novel amorphous solid dispersion (ASD) with Soluplus^® (SOL). DSC analysis and mathematical models were used to select the three appropriate PTR and SOL weight ratios. The amorphization process was carried out by a low-cost and green approach involving dry milling. An XRPD analysis confirmed the full amorphization of systems in 1:2 and 1:5 weight ratios. One glass transition (T_g) observed in DSC thermograms confirmed the complete miscibility of the systems. The mathematical models indicated strong heteronuclear interactions. SEM micrographs suggest dispersed PTR within the SOL matrix and a lack of PTR crystallinity, and showed that after the amorphization process, PTR-SOL systems had a smaller particle size and larger surface area compared with PTR and SOL. An FT-IR analysis confirmed that hydrogen bonds were responsible for stabilizing the amorphous dispersion. HPLC studies showed no decomposition of PTR after the milling process. PTR's apparent solubility and antioxidant activity after introduction into ASD increased compared to the pure compound. The amorphization process improved the apparent solubility by ~37-fold and ~28-fold for PTR-SOL, 1:2 and 1:5 w/w, respectively. The PTR-SOL 1:2 w/w system was preferred due to it having the best solubility and antioxidant activity (ABTS: IC₅₀ of 56.389 ± 0.151 µg·mL^-1 and CUPRAC: IC_0.5 of 82.52 ± 0.88 µg·mL^-1).

Pharmaceutical amorphous solid dispersion: A review of manufacturing strategies

Amorphous solid dispersions (ASDs) are popular for enhancing the solubility and bioavailability of poorly water-soluble drugs. Various approaches have been employed to produce ASDs and novel techniques are emerging. This review provides an updated overview of manufacturing techniques for preparing ASDs. As physical stability is a critical quality attribute for ASD, the impact of formulation, equipment, and process variables, together with the downstream processing on physical stability of ASDs have been discussed. Selection strategies are proposed to identify suitable manufacturing methods, which may aid in the development of ASDs with satisfactory physical stability.

Potential of solid dispersions to enhance solubility, bioavailability, and therapeutic efficacy of poorly water-soluble drugs: newer formulation techniques, current marketed scenario and patents

In the last few decades, solid dispersion (SD) technology had been studied as an approach to produce an amorphous carrier to enhance the solubility, dissolution rate, and bioavailability of poorly water-soluble drugs. The use of suitable carrier and methodology in the preparation of SDs play a significant role in the biological behavior of the SDs. SDs have been prepared using a variety of pharmaceutically acceptable polymers utilizing various novel technologies. In the recent years, much attention has been paid toward the use of novel carriers and methodologies in exploring novel types of SDs to enhance therapeutic efficacy and bioavailability. The use of novel carriers and methodologies would be very beneficial for formulation scientists to develop some SDs-based formulations for their commercial use and clinical applications. In the present review, current literature of novel methodologies for SD preparation to enhance the dissolution rate, solubility, therapeutic efficacy, and bioavailability of poorly water-soluble drugs has been summarized and analyzed. Further, the current status of SDs, patent status, and future prospects have also been discussed.

Cocrystal Solubility Advantage and Dose/Solubility Ratio Diagrams: A Mechanistic Approach To Selecting Additives and Controlling Dissolution-Supersaturation-Precipitation Behavior

Two of the main questions regarding cocrystal selection and formulation development are whether the will be stable and how fast can it dissolve the drug dose. Dissolving the drug dose may require cocrystals with a high solubility advantage over drug (SA = S_CC/S_D), but these may have limited potential to sustain drug supersaturation. Thus, we propose a twofold approach to mitigate the risk of drug precipitation by optimizing thermodynamic (SA) and kinetic factors (nucleation inhibitors). This risk can be evaluated by considering the cocrystal SA and drug dose/solubility ratio (D_0D = C_dose/S_D), which in tandem represent the maximum theoretical supersaturation that a cocrystal may generate, the driving force for drug precipitation, and the potential for dose-/solubility-limited absorption. cocrystals with SA and D_0D values above critical supersaturation are prone to rapid precipitation, often negating their utility as a solubility enhancement tool. This work presents a mechanistic approach to controlling the dissolution-supersaturation-precipitation behavior of cocrystal systems, whereby relationships between SA, D_0D, and the drug-solubilizing power of surfactants (SP_D = S_D,T/S_D,aq) are used to fine-tune cocrystal-inherent supersaturation by rational additive selection. Experimental results with danazol-vanillin cocrystal demonstrate how SA, D_0D, and SP_D are key thermodynamic parameters to understanding the kinetic cocrystal behavior and how the risks of cocrystal development may be mitigated through the mechanistic formulation design.

The Development and Validation of a Novel "Dual Cocktail" Probe for Cytochrome P450s and Transporter Functions to Evaluate Pharmacokinetic Drug-Drug and Herb-Drug Interactions

This study was designed to develop and validate a 10 probe drug cocktail named "Dual Cocktail", composed of caffeine (Cyp1a2 in rat and CYP1A2 in human, 1 mg/kg), diclofenac (Cyp2c11 in rat and CYP2C9 in human, 2 mg/kg), omeprazole (Cyp2c11 in rat and CYP2C19 in human, 2 mg/kg), dextromethorphan (Cyp2d2 in rat and CYP2D6 in human, 10 mg/kg), nifedipine (Cyp3a1 in rat and CYP3A4 in human, 0.5 mg/kg), metformin (Oct1/2 in rat and OCT1/2 in human, 0.5 mg/kg), furosemide (Oat1/3 in rat and OAT1/3 in human, 0.1 mg/kg), valsartan (Oatp2 in rat and OATP1B1/1B3 in human, 0.2 mg/kg), digoxin (P-gp in rat and human, 2 mg/kg), and methotrexate (Mrp2 in rat and MRP2 in human, 0.5 mg/kg), for the evaluation of pharmacokinetic drug-drug and herb-drug interactions through the modulation of a representative panel of CYP enzymes or transporters in rats. To ensure no interaction among the ten probe substrates, we developed a 2-step evaluation protocol. In the first step, the pharmacokinetic properties of five individual CYP probe substrates and five individual transporter substrates were compared with the pharmacokinetics of five CYP cocktail or five transporters cocktails in two groups of randomly assigned rats. Next, a pharmacokinetic comparison was conducted between the CYP or transporter cocktail group and the dual cocktail group, respectively. None of the ten comparison groups was found to be statistically significant, indicating the CYP and transporter substrate sets or dual cocktail set could be concomitantly administered in rats. The "Dual Cocktail" was further validated by assessing the metabolism of nifedipine and omeprazole, which was significantly reduced by a single oral dose of ketoconazole (10 mg/kg); however, no changes were observed in the pharmacokinetic parameters of other probe substrates. Additionally, multiple oral doses of rifampin (20 mg/kg) reduced the plasma concentrations of nifedipine and digoxin, although not any of the other substrates. In conclusion, the dual cocktail can be used to characterize potential pharmacokinetic drug-drug interactions by simultaneously monitoring the activity of multiple CYP isoforms and transporters.

Enhancement of dissolution of atorvastatin through preparation of polymeric solid dispersions using supercritical fluid technology

BACKGROUND AND PURPOSE

This study aimed at preparation of solid dispersions in order to enhance dissolution of poorly water-soluble atorvastatin using supercritical CO2 technology. Atorvastatin has poor bioavailability of 12%, mainly due to poor water solubility and dissolution. Dispersion of drugs in various hydrophilic carriers using supercritical fluid technology has been found to be an outstanding method to prepare solid dispersion.

EXPERIMENTAL APPROACH

Four different polymers were employed. These were polyvinyl pyrrolidone K30 (PVP), polyethylene glycol 6000 (PEG), Soluplus®, and chitosan. Full physicochemical characterizations were performed in addition to in vitro dissolution study.

FINDINGS / RESULTS

The used polymers enhanced the dissolution rate of atorvastatin. However, supercritical parameters affected the dissolution profile and drug loading efficiency of the prepared dispersions. High performance liquid chromatography assay indicated the stability of the prepared PEG, Soluplus® and chitosan-based dispersions. On the other hand, PVP solid dispersions were not stable and formed sticky paste. Powder X-ray diffraction showed similar patterns for PEG-based dispersions after exposure to storage condition, while the intensity of atorvastatin peaks increased after three months of storage of Soluplus® and chitosan dispersions.

CONCLUSION AND IMPLICATIONS

Supercritical fluid technology proved to have great potential to prepare dispersions for biopharmaceutics classification system (BCS) class II drugs. Dissolution enhancement of atorvastatin was achieved through successful preparation of polymeric dispersions of the drug using the supercritical technology without further addition of solvents.

Design and Characterization of Cyclosporine A-Loaded Nanofibers for Enhanced Drug Dissolution

Despite widespread use as an immunosuppressant, the therapeutic efficacy of the undecapeptide cyclosporine A (CyA) is compromised when given by the oral route because of the innate hydrophobicity of the drug molecule, potentially leading to poor aqueous solubility and bioavailability. The aim of this study was to develop and characterize nanofibers based on the water-miscible polymer polyvinylpyrrolidone (PVP), incorporating CyA preloaded into polymeric surfactants so as to promote micelle formation on hydration; therefore, this approach represents the novel combination of three dissolution enhancement methodologies, namely solid dispersion technology, micellar systems, and nanofibers with enhanced surface area. The preparation of the nanofibers was performed in two steps. First, mixed micelles composed of the water-soluble vitamin E derivative d-α-tocopheryl poly(ethylene glycol) 1000 succinate and the amphiphilic triblock polymer Pluronic F127 (Poloxamer 407) were prepared. The micelles were characterized in terms of size, surface charge, drug loading, and encapsulation efficiency using transmission electron microscopy, dynamic light scattering, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and scanning electron and atomic force microscopy analysis. Nanofibers composed of PVP and the drug-loaded surfactant system were then prepared via electrospinning, with accompanying thermal, spectroscopic, and surface topological analysis. Dissolution studies indicated an extremely rapid dissolution profile for the fibers compared to the drug alone, while wettability studies also indicated a marked decrease in contact angle compared to the drug alone. Overall, the new approach appears to offer a viable means for considerably improving the dissolution of the hydrophobic peptide CyA, with associated implications for improved oral bioavailability.

An update on the contribution of hot-melt extrusion technology to novel drug delivery in the twenty-first century: part I

INTRODUCTION

Currently, hot melt extrusion (HME) is a promising technology in the pharmaceutical industry, as evidenced by its application to manufacture various FDA-approved commercial products in the market. HME is extensively researched for enhancing the solubility and bioavailability of poor water-soluble drugs, taste masking, and modifying release in drug delivery systems. Additionally, its other novel opportunities or pharmaceutical applications, and capability for continuous manufacturing are being investigated. This efficient, industrially scalable, solvent-free, continuous process can be easily automated and coupled with other novel platforms for continuous manufacturing of pharmaceutical products.

AREAS COVERED

This review focuses on updates on solubility enhancement of poorly water-soluble drugs and process analytical tools such as UV/visible spectrophotometry; near-infrared spectroscopy; Raman spectroscopy; and rheometry for continuous manufacturing, with a special emphasis on fused deposition modeling 3D printing.

EXPERT OPINION

The strengths, weakness, opportunities, threats (SWOT) and availability of commercial products confirmed wide HME applicability in pharmaceutical research. Increased interest in continuous manufacturing processes makes HME a promising strategy for this application. However, there is a need for extensive research using process analytical tools to establish HME as a dependable continuous manufacturing process.

Curcumin-loaded self-nanomicellizing solid dispersion system: part I: development, optimization, characterization, and oral bioavailability

Curcumin (CUR) is considered as one of the most bioactive molecules ever discovered from nature due to its proven anti-inflammatory and antioxidant in both preclinical and clinical studies. Despite its proven safety and efficacy, the clinical translation of CUR into a useful therapeutic agent is still limited due to its poor oral bioavailability. To overcome its limitation and enhance oral bioavailability by improving its aqueous solubility, stability, and intestinal permeability, a novel CUR formulation (NCF) was developed using the self-nanomicellizing solid dispersion strategy. From the initial screening of polymers for their potential to improve the solubility and stability, Soluplus (SOL) was selected. The optimized NCF demonstrated over 20,000-fold improvement in aqueous solubility as a result of amorphization, hydrogen bonding interaction, and micellization determined using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, dynamic light scattering, and transmission electron microscopy. Moreover, the greater stabilizing effect in alkaline pH and light was observed. Furthermore, significant enhancement of dissolution and permeability of CUR across everted sacs of rat small intestine were noticed. Pharmacokinetic studies demonstrated that the oral bioavailability of CUR was increased 117 and 17-fold in case of NCF and physical mixture of CUR and SOL compared to CUR suspension. These results suggest NCF identified as a promising new approach for repositioning of CUR for pharmaceutical application by enhancing the oral bioavailability of CUR. The findings herein stimulate further in vivo evaluations and clinical tests of NCF.

Hot Melt Extrusion: Highlighting Physicochemical Factors to Be Investigated While Designing and Optimizing a Hot Melt Extrusion Process

Hot-melt extrusion (HME) is a well-accepted and extensively studied method for preparing numerous types of drug delivery systems and dosage forms. It offers several advantages: no solvents are required, it is easy to scale up and employ on the industrial level, and, in particular, it offers the possibility of improving drug bioavailability. HME involves the mixing of a drug with one or more excipients, in general polymers and even plasticizers, which can melt, often forming a solid dispersion of the drug in the polymer. The molten mass is extruded and cooled, giving rise to a solid material with designed properties. This process, which can be realized using different kinds of special equipment, may involve modifications in the drug physicochemical properties, such as chemical, thermal and mechanical characteristics thus affecting the drug physicochemical stability and bioavailability. During process optimization, the evaluation of the drug solid state and stability is thus of paramount importance to guarantee stable drug properties for the duration of the drug product shelf life. This manuscript reviews the most important physicochemical factors that should be investigated while designing and optimizing a hot melt extrusion process, and by extension, during the different pre-formulation, formulation and process, and post-formulation phases. It offers a comprehensive evaluation of the chemical and thermal stability of extrudates, the solid physical state of extrudates, possible drug-polymer interactions, the miscibility/solubility of the drug-polymer system, the rheological properties of extrudates, the physicomechanical properties of films produced by hot melt extrusion, and drug particle dissolution from extrudates. It draws upon the last ten years of research, extending inquiry as broadly as possible.

A Repurposed Drug for Brain Cancer: Enhanced Atovaquone Amorphous Solid Dispersion by Combining a Spontaneously Emulsifying Component with a Polymer Carrier

Glioblastoma multiforme (GBM) is the most common and lethal central nervous system tumor. Recently, atovaquone has shown inhibition of signal transducer and activator transcription 3, a promising target for GBM therapy. However, it is currently unable to achieve therapeutic drug concentrations in the brain with the currently reported and marketed formulations. The present study sought to explore the efficacy of atovaquone against GBM as well as develop a formulation of atovaquone that would improve oral bioavailability, resulting in higher amounts of drug delivered to the brain. Atovaquone was formulated as an amorphous solid dispersion using an optimized formulation containing a polymer and a spontaneously emulsifying component (SEC) with greatly improved wetting, disintegration, dispersibility, and dissolution properties. Atovaquone demonstrated cytotoxicity against GBM cell lines as well as provided a confirmed target for atovaquone brain concentrations in in vitro cell viability studies. This new formulation approach was then assessed in a proof-of-concept in vivo exposure study. Based on these results, the enhanced amorphous solid dispersion is promising for providing therapeutically effective brain levels of atovaquone for the treatment of GBM.

Application of Soluplus to Improve the Flowability and Dissolution of Baicalein Phospholipid Complex

In this study, a novel ternary complex system (TCS) composed of baicalein, phospholipids, and Soluplus was prepared to improve the flowability and dissolution for baicalein phospholipid complex (BPC). TCS was characterized using differential scanning calorimetry (DSC), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The flowability, solubility, oil–water partition coefficient, in vitro dissolution, and in vivo pharmacokinetics of the system were also evaluated. DSC, IR, PXRD, and SEM data confirmed that the crystal form of baicalein disappeared in BPC and TCS. Furthermore, the angle of repose of TCS of 35° indicated an improvement in flowability, and solubility increased by approximately eight-fold in distilled water when TCS was compared with BPC (41.00 ± 4.89 μg/mL vs. 5.00 ± 0.16 μg/mL). Approximately 91.24% of TCS was released at the end of 60 min in 0.5% SDS (pH = 6.8), which suggested that TCS could improve the dissolution velocity and extent. Moreover, TCS exhibited a considerable enhancement in bioavailability with higher peak plasma concentration (25.55 μg/mL vs. 6.05 μg/mL) and increased AUC_0–∞ (62.47 μg·h/mL vs. 50.48 μg·h/mL) with 123.75% relative bioavailability compared with BPC. Thus, Soluplus achieved the purpose of improving the flowability and solubility of baicalein phospholipid complexes. The application of Soluplus to phospholipid complexes has great potential.

Challenges and Strategies in Thermal Processing of Amorphous Solid Dispersions: A Review

Thermal processing of amorphous solid dispersions continues to gain interest in the pharmaceutical industry, as evident by several recently approved commercial products. Still, a number of pharmaceutical polymer carriers exhibit thermal or viscoelastic limitations in thermal processing, especially at smaller scales. Additionally, active pharmaceutical ingredients with high melting points and/or that are thermally labile present their own specific challenges. This review will outline a number of formulation and process-driven strategies to enable thermal processing of challenging compositions. These include the use of traditional plasticizers and surfactants, temporary plasticizers utilizing sub- or supercritical carbon dioxide, designer polymers tailored for hot-melt extrusion processing, and KinetiSol® Dispersing technology. Recent case studies of each strategy will be described along with potential benefits and limitations.

Development of megestrol acetate solid dispersion nanoparticles for enhanced oral delivery by using a supercritical antisolvent process

In the present study, solid dispersion nanoparticles with a hydrophilic polymer and surfactant were developed using the supercritical antisolvent (SAS) process to improve the dissolution and oral absorption of megestrol acetate. The physicochemical properties of the megestrol acetate solid dispersion nanoparticles were characterized using scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and a particle-size analyzer. The dissolution and oral bioavailability of the nanoparticles were also evaluated in rats. The mean particle size of all solid dispersion nanoparticles that were prepared was <500 nm. Powder X-ray diffraction and differential scanning calorimetry measurements showed that megestrol acetate was present in an amorphous or molecular dispersion state within the solid dispersion nanoparticles. Hydroxypropylmethyl cellulose (HPMC) solid dispersion nanoparticles significantly increased the maximum dissolution when compared with polyvinylpyrrolidone K30 solid dispersion nanoparticles. The extent and rate of dissolution of megestrol acetate increased after the addition of a surfactant into the HPMC solid dispersion nanoparticles. The most effective surfactant was Ryoto sugar ester L1695, followed by D-α-tocopheryl polyethylene glycol 1000 succinate. In this study, the solid dispersion nanoparticles with a drug:HPMC:Ryoto sugar ester L1695 ratio of 1:2:1 showed >95% rapid dissolution within 30 minutes, in addition to good oral bioavailability, with approximately 4.0- and 5.5-fold higher area under the curve (0–24 hours) and maximum concentration, respectively, than raw megestrol acetate powder. These results suggest that the preparation of megestrol acetate solid dispersion nanoparticles using the supercritical antisolvent process is a promising approach to improve the dissolution and absorption properties of megestrol acetate.