Improvement of Oral Absorption of Poorly Water-Soluble Drugs by Solid Dispersions with Amphiphilic Phospholipid Polymer

Combining porous starch and polyoxyethylene hydrogenated castor oil RH40 to enhance the solubility, stability, and bioavailability of bisdemethoxycurcumin

Bisdemethoxycurcumin (BDC) is an important ingredient derived from the food spice turmeric. Although BDC exhibits various pharmacological effects, it is characterized by poor water solubility and limited stability under light. Considering that the high specific surface area of porous starch (PS) renders it an ideal carrier for the encapsulation of active compounds, and polyoxyethylene‑hydrogenated castor oil RH40 (RH40) is an effective solubilizer for BDC, the current study optimized the PS/RH40/BDC formulation to combine these advantages. Consequently, a PS/RH40/BDC ratio of 10:3:1 was identified as optimal (RH-PS/BDC). Characterization using scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and stability testing indicated that BDC was amorphously encapsulated within the RH-PS system, thereby leading to enhanced stability and solubility. Furthermore, cellular uptake experiments revealed a significant increase of RH-PS/BDC. In terms of the enhancement mechanism, RH40 can reduce cell membrane fluidity and open tight junctions between intestinal epithelial cells, thereby facilitating BDC absorption. In vivo pharmacodynamic analysis confirmed that RH-PS/BDC effectively inhibited LPS-induced cerebral neuritis. Overall, this study demonstrates the role of PS in combination with RH40 in enhancing the stability and bioavailability of BDC. This simple and efficient preparation strategy is promising for future research and product development.

Multi-functional Chitosan Polymeric Micelles for improving the oral bioavailability of Paclitaxel based on synergistic effect

A novel multi-functional micelle delivery system was developed for enhancing the oral absorption of paclitaxel (PTX). The delivery carriers were constructed by modifying chitosan-stearic acid (CS-SA) micelles with L-carnitine (LC) and co-encapsulating quercetin (Que), and the PTX-loaded micelles were prepared by film-sonication dispersing technique. The as-prepared micelles showed homogeneous spherical shapes with a small particle size of 148.3 ± 1.7 nm, high drug loading of 7.05% and low critical micelle concentration (CMC) of 16.89 µg/ml. Compared to the in-house PTX formulation similar to the commercial injection Taxol™, the target PTX-loaded micelles had obvious sustained-release effects and exhibited an oral relative bioavailability of 168.08%. The cellular uptake studies of Caco-2 cells confirmed the micellar modification of LC and the co-loading of Que played important roles in promoting the absorption of drug loaded in micelles. The CYP3A4 enzyme test demonstrated the micelles had an inhibitory effect on the metabolic enzyme due to the presence of Que. These findings confirmed the potential of the multi-functional chitosan polymeric micelles based on synergistic effect as an effective oral delivery system.

Self-nanomicellizing solid dispersion: A promising platform for oral drug delivery

Amorphous solid dispersion (ASD) has been widely used to enhance the oral bioavailability of water-insoluble drugs for oral delivery because of its advantages of enhancing solubility and dissolution rate. However, the problems related to drug recrystallization after drug dissolution in media or body fluid have constrained its application. Recently, a self-nanomicellizing solid dispersion (SNMSD) has been developed by incorporating self-micellizing polymers as carriers to settle the problems, markedly improving the ability of supersaturation maintenance and enhancing the oral bioavailability of drug. Spontaneous formation and stability of the self-nanomicelle (SNM) have been proved to be the key to supersaturation maintenance of SNMSD system. This offers a novel research direction for maintaining supersaturation and enhancing the bioavailability of ASDs. To delve into the advantages of SNMSDs, we provide a concise review introducing the formation mechanism, characterization methods and stability of SNMs, emphasizing the advantages of SNMSDs for oral drug delivery facilitated by SNM formation, and discussing relevant research prospects.

Curcumin amorphous solid dispersions benefit from hydroxypropyl methylcellulose E50 to perform enhanced anti-inflammatory effects

The solubility and permeability enhancement of curcumin (Cur) is crucial for its manufacture and application in medical field. Herein, Cur amorphous solid dispersions (ASDs) with enhanced drug solubility and permeability was formulated by Eudragit EPO (EuD) and biological macromolecules of hydroxypropyl methylcellulose E50 (HPMC), and significant functions of HPMC for Cur ASDs were mainly studied. The results showed that the mean particle size of Cur decreased from more than 300 nm to less than 200 nm with the addition of HPMC in excipient aqueous solution evidenced by dynamic light scattering result, confirming that HPMC had the ability to inhibit crystallization by lowering drug-rich droplets in the initial mixing process. Innovatively for molecular dynamic modeling study, crystalline Cur molecules in EuD medium trended to aggregate while not for EuD/HPMC 1:1 and EuD/HPMC 3:1 medium. HPMC functioned as surfactant converted the arrangement of phospholipid bilayers to un-ordered, and un-ordered state of phospholipids lead to the enhancement of Cur transmembrane using HPMC as auxiliary excipient. Cur-EuD/HPMC 3:1 contributed greatly to the Cur permeability, leading to obtain superior relative oral bioavailability and anti-inflammatory effect. Cur ASDs with proper amount of HPMC can be rendered as outstanding therapeutic strategy for medical application.

How can Electrospinning Further Service Well for Pharmaceutical Researches?

The past two decades have witnessed the enormous success and progress of electrospinning, as well as its broad and useful applications in pharmaceutics as a laboratory pharmaceutical nanotechnology. Everything in the past is a preface, in which the large screen opens for electrospinning and electrospun nanofibers (particularly those multiple-fluid electrospinning processes and the related multiple-chamber nanostructures) to stride into a new stage and the real commercial applications. In this commentary, four hot regions are identified for the further progress of the applications of electrospinning in pharmaceutics, in which electrospinning and its products can provide more and better services to the development of pharmaceutics.

Twin Screw Melt Granulation: A Single Step Approach for Developing Self-Emulsifying Drug Delivery System for Lipophilic Drugs

The current research aims to improve the solubility of the poorly soluble drug, i.e., ibuprofen, by developing self-emulsifying drug delivery systems (SEDDS) utilizing a twin screw melt granulation (TSMG) approach. Gelucire® 44/14, Gelucire® 48/16, and Transcutol® HP were screened as suitable excipients for developing the SEDDS formulations. Initially, liquid SEDDS (L-SEDDS) were developed with oil concentrations between 20-50% w/w and surfactant to co-surfactant ratios of 2:1, 4:1, 6:1. The stable formulations of L-SEDDS were transformed into solid SEDDS (S-SEDDS) using a suitable adsorbent carrier and compressed into tablets (T-SEDDS). The S-SEDDS has improved flow, drug release profiles, and permeability compared to pure drugs. The existence of the drug in an amorphous state was confirmed by differential scanning calorimetry (DSC) and powder X-ray diffraction analysis (PXRD). The formulations with 20% w/w and 30% w/w of oil concentration and a 4:1 ratio of surfactant to co-surfactant have resulted in a stable homogeneous emulsion with a globule size of 14.67 ± 0.23 nm and 18.54 ± 0.55 nm. The compressed tablets were found stable after six months of storage at accelerated and long-term conditions. This shows the suitability of the TSMG approach as a single-step continuous manufacturing process for developing S-SEDDS formulations.

Optimization of O/W Emulsion Solvent Evaporation Method for Itraconazole Sustained Release Microspheres

Itraconazole, a commonly used antifungal drug in the clinic approved by U.S. Food and Drug Administration (FDA), has been gradually found to have anti-tumor, angiogenesis inhibition and other pharmacological activities. However, its poor water solubility and potential toxicity limited its clinical application. In order to improve the water solubility and reduce the side effects caused by the high concentration of itraconazole, a novel preparation method of itraconazole sustained release microspheres was established in this study. Firstly, five kinds of polylactic acid-glycolic acid (PLGA) microspheres loaded with itraconazole were prepared by oil/water (O/W) emulsion solvent evaporation and then characterized by infrared spectroscopy. Then the particle size and morphology of the microspheres were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). After that, the particle size distribution, drug loading rate, entrapment efficiency, and drug release experiments were evaluated. Our results showed the microspheres prepared in this study had uniform particle size distribution and good integrity. Further study found that the average drug loading of the five kinds of microspheres prepared with PLGA 7505, PLGA 7510, PLGA 7520, PLGA 5020 and PLGA 0020 were 16.88, 17.72, 16.72, 16.57, and 16.64%, respectively, and the encapsulation rate all reached about 100%. More surprisingly, the release experimental results showed that the microspheres prepared with PLGA 7520 did not show sudden release, showing good sustained release performance and high drug release rate. To sum up, this study optimized the preparation method of sustained-release microspheres without sudden release, which provides a new solution for the delivery of itraconazole in the clinic.

[Solubilization of Poorly Water-soluble Drugs with Amphiphilic Phospholipid Polymers]

Most drug candidates developed in recent years are poorly water-soluble, which is a key challenge in pharmaceutical science. Various solubilization methods have been investigated thus far, most of which require solubilizers that provide a local hydrophobic environment wherein a drug can dissolve or induce interactions with drug molecules. We have focused on amphiphilic 2-methacryloyloxyethyl phosphoryl choline (MPC) polymers. In addition to the ease of molecular design of amphiphilic MPC polymers owing to their chemical structures, they have been reported to possess high biocompatibility in various biomaterial applications. Additionally, amphiphilic MPC polymers have been applied in the pharmaceutical field, especially in solubilization. We have qualitatively and quantitatively evaluated the effects of the chemical structure and physical properties of the solubilizer on the MPC polymers. In particular, MPC polymers with different chemical structures were designed and synthesized. The inner polarity and molecular mobility in the polymer aggregates were evaluated, indicating that the intrinsic properties reflect the chemical structure of the polymer. Additionally, amphiphilic MPC polymers were used to improve the solubility of poorly water-soluble drugs and as solid dispersion carriers, and they exhibited superior solubilizing abilities compared to a commonly used polymer. Furthermore, the solubility of biopharmaceuticals, such as peptides, was improved. It is possible to design and synthesize optimal structures based on the polarity of the hydrophobic environment and the intermolecular interaction with a drug. This research provides a unified interpretation of drugs and efficiently summarizes knowledge about drug development, which will facilitate the efficient and rapid development of drug formulations.