Spatial-thermodynamic understanding of stabilization mechanism using computational approaches and molecular-level elucidation of the mechanism of crystal transformation in polymorphic irbesartan nanosuspensions

Effect of PVP and HPMC on production of indomethacin amorphous nanoparticles: experiments and molecular dynamics simulations

OBJECTIVE

This study investigated the effect of molecular interactions between drug and polymers on preparation of nanoamorphous indomethacin (IND) through milling of solid dispersions (SDs).

SIGNIFICANCE

The polymer selection (molecular interaction) emerged as a critical factor in the dynamic milling process for achieving nanoamorphous drug.

METHODS

Polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC) were selected as models. Amorphous dispersions were used to prepare nanoamorphous drugs by applying wet milling. Molecular simulations were employed to elucidate the molecular mechanisms of drug-polymer miscibility, interaction energy, and molecular migration.

RESULTS

Both PVP and HPMC related SDs could be nanosized after milling. The rate of size reduction might be related to the solid state of the dispersions. The combination of amorphous PVP SDs with reduced particle size significantly improved the dissolution rate of IND. However, HPMC-based samples exhibited recrystallization during milling. Molecular simulation indicated that PVP formed strong molecular interaction with the drug to maintain the amorphous form, which contributed to avoid recrystallization induced by the external milling forces. The radial distribution function of hydrated IND/HPMC amorphous cells demonstrated the absence of hydrogen bonding interactions between IND and HPMC.

CONCLUSION

PVP contributed to maintain the amorphous state during the milling process, which resulted from the higher molecular binding energy compared to HPMC. Controlled milling of amorphous SD with optimized polymer selection could simultaneously achieve nanoamorphous particle and enhanced dissolution rate.

Comparisons of the bioavailability of icariin, icariside II, and epimedin C in rats after oral administration of total flavonoids of Epimedium brevicornu Maxim. and its three formulations

The low bioavailability of insoluble flavonoids in the total flavonoids of Epimedium brevicornu Maxim. (TFE) severely hindered its clinical efficacy exertion. This research attempted to evaluate the promoting effects of pharmaceutical strategies, including nanosuspensions (NS), cyclodextrin inclusion complexes (CD), and solid dispersions (SD), on the oral absorption of active components in TFE. A rapid ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to quantify ten pentenyl flavonoids of TFE in rat plasma. Good linearity was presented within the expected ranges (0.1 ∼ 10 ng/mL) in the calibration curves for ten analytes with an acceptable intra- and inter-day precision and accuracy of < 11.34 % and ± 11.91 %, respectively. By employing this selective UPLC-MS/MS method, the full-scale concentration-time curve for icariin (ICA), icariin II (ICA II), and epimedin C (EPI C) were drawn after oral administration of the crude TFE and its formulations. The results showed that the relative bioavailability (Frel) of ICA and ICA II in the NS and CD formulations were 228-295 % when the crude TFE was as a reference, whereas the Frel of ICA, ICA II, and EPI C in SD formulation were 416 %, 234 %, and 112 %, respectively. The findings suggest that SD technology holds significant promise for enhancing the oral bioavailability of various poorly soluble ingredients in herbal extracts, such as TFE, and for augmenting their therapeutic capabilities in clinical practice.

Comparison of Solid Self-Nanoemulsifying Systems and Surface-Coated Microspheres: Improving Oral Bioavailability of Niclosamide

Purpose

This study aimed to develop a solid self-nanoemulsifying drug delivery system (SNEDDS) and surface-coated microspheres to improve the oral bioavailability of niclosamide.

Methods

A solubility screening study showed that liquid SNEDDS, prepared using an optimized volume ratio of corn oil, Cremophor RH40, and Tween 80 (20:24:56), formed nanoemulsions with the smallest droplet size. Niclosamide was incorporated into this liquid SNEDDS and spray-dried with calcium silicate to produce solid SNEDDS. Surface-coated microspheres were prepared using sodium alginate and poloxamer 407 and optimized through solubility and dissolution tests. Scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction were used to evaluate the physicochemical properties of the prepared solid SNEDDS, surface-coated microspheres, and the drug alone. The solubility, dissolution, and oral bioavailability were also assessed.

Results

Physicochemical evaluation demonstrated that niclosamide was converted to an amorphous state in the Solid SNEDDS formulation, with enhanced solubility and oral bioavailability. In comparison to niclosamide alone, solid SNEDDS exhibited an increase in drug solubility (approximately 2500-fold vs 158-fold) and oral bioavailability (approximately 10-fold vs 1.65-fold), significantly outperforming surface-coated microspheres.

Conclusion

This solid SNEDDS formulation may be an excellent candidate for niclosamide with improved oral bioavailability for repurposing.

Examine stability polyvinyl alcohol-stabilized nanosuspensions to overcome the challenge of poor drug solubility utilizing molecular dynamic simulation

The pharmaceutical industry faces a significant challenge from the low water solubility of nearly 90% of newly developed Active Pharmaceutical Ingredients (APIs). Despite extensive efforts to improve solubility, approximately 40% of these APIs encounter commercialization hurdles, impacting drug efficacy. In this context, a promising strategy will be introduced in which nanosuspensions, particularly polyvinyl alcohol (PVA) as a stabilizer, are applied to increase drug solubility. In this work using molecular dynamics simulations, the nanosuspension of four poorly water-soluble drugs (flurbiprofen, bezafibrate, miconazole, and phenytoin) stabilized with PVA is investigated. The simulation data showed van der Waals energies between polyvinyl alcohol with flurbiprofen and bezafibrate are - 101.12 and - 58.42 kJ/mol, respectively. The results indicate that PVA is an effective stabilizer for these drugs, and superior interactions are obtained with flurbiprofen and bezafibrate. The study also explores the impact of PVA on water molecule diffusion, providing insights into the stability of nanosuspensions. Obtained results also provide valuable insights into hydrogen bond formation, diffusion coefficients, and nanosuspension stability, contributing to the rational design and optimization of pharmaceutical formulations.

Recent advances in nanocrystal-based technologies applied for ocular drug delivery

INTRODUCTION

The intricate physiological barriers of the eye and the limited volume of eye drops impede efficient delivery of poorly water-soluble drugs. In the last decade, nanocrystals have emerged as versatile drug delivery systems in various administration routes from bench to bedside. The unique superiorities of nanocrystals, mainly embodied in high drug-loading capacity, good mucosal adhesion and penetration, and greatly improved drug solubility, reveal a promising prospect for ocular delivery of poorly water-soluble drugs.

AREAS COVERED

This article focuses on the ophthalmic nanocrystal technologies and products that are in the literature, clinical trials, and even on the market. The recent research progress in the preparation, ocular application, and absorption of nanocrystals are highlighted, and the pros and cons of nanocrystals in overcoming the physiological barriers of the eye are also summarized.

EXPERT OPINION

Nanocrystals have demonstrated success as glucocorticoid eye drops in the treatment of anterior segment diseases. However, the thermodynamic stability of nanocrystals remains the major challenge in product development. New technologies for efficiently optimizing stabilizers and sterilization processes are still expected. Strategies to confer more diverse functions via surface modification are also worth exploration to improve the potential of nanocrystals in delivering poorly water-soluble drugs to posterior segment of the eye.

Nanosuspensions technology as a master key for nature products drug delivery and In vivo fate

The drug nanosuspensions is a universal formulation approach for improved drug delivery of hydrophobic drugs and one the most promising approaches for increasing the biopharmaceutical performance of poorly water-soluble drug substances, especially for nature products. This review aimed to summarize the nanosuspensions preparation approaches and the main technological difficulties encountered in nanosuspensions development, such as guidelines for stabilizers screening, in vivo fate of the intravenously administrated nanosuspensions, and how to realize the intravenously target delivery was reviewed. Furthermore, challenges of nanosuspensions for the nature products delivery also was discussed and commented. Therefore, it hoped to provide reference and assistance for the nanosuspensions production, stabilizers usage, and predictability of in vivo fate and controllability of targeting delivery of the nature products nanosuspensions.