Drug Nanocrystals: Focus on Brain Delivery from Therapeutic to Diagnostic Applications

Enhanced in vivo performance of topical ocular acetazolamide nanocrystals: A novel approach for glaucoma treatment

High intraocular pressure (IOP) is the main risk factor for glaucoma progression. Acetazolamide (AZM) presents a potent IOP-lowering effect but is only administered orally due to its low aqueous solubility and ocular permeability. This study aimed to develop AZM nanocrystals (AZM-NC) as an alternative for its topical ocular delivery. AZM-NC were obtained by wet bead milling technique followed by spray-drying, and a mixture design study was conducted to evaluate the optimal drug-to-stabilizer ratio regarding colloidal properties and stability. AZM-NC exhibited an average particle size of 299.7 ± 8.8 nm, a polydispersity index of 0.13 ± 0.01, and a zeta potential of -29.0 ± 0.9 mV, which remained mostly unchanged for at least 60 days when the dried powder was stored at room temperature. Fourier-transformed spectroscopy and powder X-ray diffraction analyses revealed no chemical or crystallinity changes in AZM-NC compared with AZM, respectively. Additionally, AZM-NC demonstrated increased drug saturation concentration, globular shapes, and higher adhesive properties than normal-sized AZM powder. Topical ocular administration of AZM-NC in albino male rabbits showed no clinical signs of ocular damage. Further, in vivo studies revealed a significant IOP reduction of up to 32 % of the basal IOP (-4.8 ± 1.2 mmHg, p < 0.05) in normotensive rabbit eyes (n = 7), after 4 h of AZM-NC suspension topical application, compared to groups treated with AZM suspension, normal saline solution and, AZOPT® (-1.8 ± 1.4 mmHg). Thus, AZM-NC could present a promising approach for developing an eye drop formulation for the localized management of glaucoma.

An Approach to Enhance the Solubility of an Atypical Antipsychotic Drug, Aripiprazole: Design, Characterization, and Evaluation of Arabinoxylan-Based Nanoparticles

Introduction

Natural polymers have emerged as versatile and sustainable alternatives to synthetic polymers in pharmaceutical and biomedical applications. This study focuses on the extraction of arabinoxylan (AX) from maize husk and its potential as a promising excipient to enhance the solubility and oral bioavailability of Aripiprazole (APZ), a poorly water-soluble antipsychotic drug, offering a robust strategy for overcoming challenges associated with hydrophobic drugs.

Methods

APZ-loaded AX nanoparticles were synthesized using the ionotropic gelation technique. The formulation with the highest encapsulation efficiency designated as FN4 was selected for detailed characterization. Various analytical techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC), were employed to assess the morphological, crystalline, and thermal properties of the nanoparticles. In vitro release studies were conducted on both simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8) to evaluate drug dissolution behaviour. The everted sac method was utilized to assess the permeation and transport of APZ from the AX-based nanoparticles.

Results

The FN4 formulation exhibited an encapsulation efficiency of 88.9% ± 1.77%, with a particle size of 284.4 nm, a polydispersity index (PDI) of 0.346, and a zeta potential of 20.7 mV. SEM analysis revealed a uniform distribution of polyhedral-shaped nanoparticles. XRD and DSC analyses indicated that APZ was in an amorphous state within the nanoparticles. Drug release was more pronounced at pH 6.8, with the AX nanoparticles showing sustained release. The everted sac method demonstrated enhanced permeation of APZ across intestinal membranes, supporting the potential of AX nanoparticles in improving drug absorption.

Discussion

The AX-based nanoparticle formulation significantly improved the solubility, pH-dependent release profile, and sustained release of APZ, offering a promising strategy to enhance the oral bioavailability of poorly soluble drugs. These findings suggest that AX nanoparticles could serve as an effective delivery system for enhancing the therapeutic potential of hydrophobic drugs like APZ.

Nanocrystals for Intravenous Drug Delivery: Composition Development, Preparation Methods and Applications in Oncology

Intravenous routes of drug delivery are widely used in clinical practice due to the advantages of fast onset of action and avoidance of first-pass effect. Still, it is difficult to develop poorly water-soluble drugs for intravenous administration. In recent years, the application of nanocrystal technology has become more and more widespread, mainly involving reducing the particle size to the nanoparticle size range and improving its physicochemical properties to enhance the bioavailability of drugs. Intravenous nanocrystals (INCs) can show unique advantages in the vasculature, with their high drug loading capacity, low toxicity, and overcoming low solubility, which makes them a new solution in tumor therapy. In addition, INCs are mainly suspended in aqueous/oil phase media, which makes them easy to inject. Therefore, INCs may serve as a novel strategy to address poor water solubility, low bioavailability, and associated toxicity. This review contains the compositional development of INCs, and preparation methods, and provides some insights into their application in oncology.

Transforming Medicine: Cutting-Edge Applications of Nanoscale Materials in Drug Delivery

Since their inception in the early 1960s, the development and use of nanoscale materials have progressed tremendously, and their roles in diverse fields ranging from human health to energy and electronics are undeniable. The application of nanotechnology inventions has revolutionized many aspects of everyday life including various medical applications and specifically drug delivery systems, maximizing the therapeutic efficacy of the contained drugs by means of bioavailability enhancement or minimization of adverse effects. In this review, we utilize the CAS Content Collection, a vast repository of scientific information extracted from journal and patent publications, to analyze trends in nanoscience research relevant to drug delivery in an effort to provide a comprehensive and detailed picture of the use of nanotechnology in this field. We examine the publication landscape in the area to provide insights into current knowledge advances and developments. We review the major classes of nanosized drug delivery systems, their delivery routes, and targeted diseases. We outline the most discussed concepts and assess the advantages of various nanocarriers. The objective of this review is to provide a broad overview of the evolving landscape of current knowledge regarding nanosized drug delivery systems, to outline challenges, and to evaluate growth opportunities. The merit of the review stems from the extensive, wide-ranging coverage of the most up-to-date scientific information, allowing unmatched breadth of landscape analysis and in-depth insights.

Strategies to Enhance Nanocrystal Formulations for Overcoming Physiological Barriers Across Diverse Routes of Administration

Poor aqueous solubility and bioavailability limit the translation of new drug candidates into clinical applications. Nanocrystal formulations offer a promising approach for improving the dissolution rate and saturation solubility. These formulations are applicable for various routes of administration, with each presenting unique opportunities and challenges posed by the physiological barriers. The development of nanocrystal formulation requires comprehensive understanding of these barriers and the biological environment, along with strategic modulation of particle size, surface properties, and charge to facilitate improved bioavailability to the target site. This review focuses on applications of nanocrystals for diverse administration routes and strategies in overcoming anatomical and physiological delivery barriers. The orally administered nanocrystals benefit from increased solubility, prolonged gastrointestinal retention, and enhanced permeation. However, the nanocrystals, due to their small size and high surface area, are susceptible to aggregation in the presence of gastric fluids and are more prone to enzymatic degradation compared to the macrocrystalline form. Although nanocrystal formulations are composed of pure API, the application of excipients like stabilizers reduces the aggregation and improves formulation stability, solubility, and bioavailability. Some excipients can facilitate sustained drug release. Emerging research in nanocrystals include their application in blood-brain barrier transport, intranasal delivery, stimuli responsiveness, multifunctionality, and diagnostic purposes. However, the challenges related to toxicity, scale-up, and clinical translation still need further attention. Overall, nanocrystal engineering serves as a versatile platform for expanding the therapeutic potential of insoluble drugs and enabling dose reduction for existing drugs, which can minimize toxicity and improve bioavailability at lower dosages.

Drug nanocrystals: Surface engineering and its applications in targeted delivery

Drug nanocrystals have received significant attention in drug development due to their enhanced dissolution rate and improved water solubility, making them effective in overcoming issues related to drug hydrophobicity, thereby improving drug bioavailability and treatment effectiveness. Recent advances in preparation techniques have facilitated research on drug surface properties, leading to valuable surface engineering strategies. Surface modification can stabilize drug nanocrystals, making them suitable for versatile drug delivery platforms. Functionalized ligands further enhance the potential for targeted delivery, enabling precision medicine. This review focuses on the surface engineering of drug nanocrystals, discussing various preparation methods, surface ligand design strategies, and their applications in targeted drug delivery, especially for cancer treatments. Finally, challenges and future directions are also discussed to promote the development of drug nanocrystals. The surface engineering of drug nanocrystals promises new opportunities for treating complex and chronic diseases while broadening the application of drug delivery systems.

Biomimetic nanoplatform treats myocardial ischemia/reperfusion injury by synergistically promoting angiogenesis and inhibiting inflammation

After myocardial ischemia/reperfusion injury (MI/RI), endothelial cell injury causes impaired angiogenesis and obstruction of microcirculation, resulting in an inflammatory outburst that exacerbates the damage. Therefore, synergistic blood vessel repair and inflammation inhibition are effective therapeutic strategies. In this study, we developed a platelet membrane (PM)-encapsulated baicalin nanocrystalline (BA NC) nanoplatform with a high drug load, BA NC@PM, which co-target to endothelial cells and macrophages through the transmembrane proteins of the PM to promote angiogenesis and achieve anti-inflammatory effects. In vitro cell scratch assays and transwell assay manifested that BA NC@PM could promote endothelial cell migration, as well as increase mRNA expression of CD31 and VEGF in the heart after treatment of MI/RI mice, suggesting its favorable vascular repair function. In addition, the preparation significantly reduced the expression of pro-inflammatory factors and increased the expression of anti-inflammatory factors in plasma, promoting the polarization of macrophages. Our study highlights a strategy for enhancing the treatment of MI/RI by promoting angiogenesis and regulating macrophage polarization via the biomimetic BA NC@PM nanoplatform.

Effect of Particle Size on Physical Properties, Dissolution, In Vitro Antioxidant Activity, and In Vivo Hepatoprotective Properties of Tetrastigma hemsleyanum Diels et Gilg Powders

Objective: The aim of this study was to analyze the effects of different particle sizes of Tetrastigma hemsleyanum Diels et Gilg (TDG) powders on physical properties, dissolution, in vitro antioxidant activity, and in vivo hepatoprotective properties. Methods: The particle size of TDG coarse powders (TDG-CP), TDG fine powders (TDG-FP), and TDG micro powders (TDG-MP) were measured by a laser particle size analyzer. The physical properties were measured according to the latest version of the Chinese Pharmacopoeia (Committee Chinese Pharmacopoeia 2020). The content of the total flavonoids, total polysaccharides, kaempferol-3-O-rutinoside, and rutin of TDG powders were determined using the NaNO2-Al (NO3)3 colorimetric method, the sulphate-phenol colorimetric method, and HPLC, respectively. In vitro dissolution and antioxidant activity were determined by the paddle method in phosphate buffer (pH 6.8) and the DPPH radical scavenging method, respectively. In addition, the liver tissue pathology was evaluated by hematoxylin and eosin staining (H&E), and the AST and ALT activities were measured by automatic biochemical analyzer. The superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) activities were measured by using commercial analysis kits. Results: As the particle size decreases, the fluidity of TDG powders decreased and the porosity increased. In addition, there were no significant differences in physical properties between low temperature pulverized powders and room temperature pulverized powders. The final dissolution rates of the four bioactive ingredients in TDG-MP were found to be 85.06%, 85.61%, 83.88%, and 83.26%, respectively, whereas in TDG-CP, the dissolution rates were significantly lower at 18.79%, 17.96%, 22.46%, and 24.35%. The EC50 values of TDG-CP, TDG-FP, and TDG-MP on DPPH scavenging activity were 0.82, 0.31, and 0.10 mg/mL, respectively. The AST and ALT activities of the TDG-FP group and the TDG-MP group were significantly decreased and the SOD, CAT, and GSH activities were significantly increased when compared with that of the model group. The inflammatory cell infiltration and vacuolar degeneration of liver cells in the TDG-FP group and the TDG-MP group were significantly improved. Conclusions: The particle size of TDG powders had a significant effect on the physical properties and in vivo bioactivity. TDG pulverized to a fine particle size or smaller is a promising approach for clinical applications with improved physicochemical and biological properties.

Cannabidiol and its application in the treatment of oral diseases: therapeutic potentials, routes of administration and prospects

Cannabidiol (CBD), one of the most important active ingredients in cannabis, has been reported to have some pharmacological effects such as antibacterial and analgesic effects, and to have therapeutic potential in the treatment of oral diseases such as oral cancer, gingivitis and periodontal diseases. However, there is a lack of relevant systematic research and reviews. Therefore, based on the etiology and clinical symptoms of several common oral diseases, this paper focuses on the therapeutic potential of CBD in periodontal diseases, pulp diseases, oral mucosal diseases, oral cancer and temporomandibular joint diseases. The pharmacological effects of CBD and the distribution and function of its receptors in the oral cavity are also summarized. In order to provide reference for future research and further clinical application of CBD, we also summarize several possible routes of administration and corresponding characteristics. Finally, the challenges faced while applying CBD clinically and possible solutions are discussed, and we also look to the future.

Fabrication and in vitro/vivo evaluation of quercetin nanocrystals stabilized by glycyrrhizic acid for liver targeted drug delivery

The purpose of this study was to design novel drug nanocrystals (NCs) stabilized by glycyrrhizic acid (GL) for achieving liver targeted drug delivery due to the presence of GL receptor in the hepatocytes. Quercetin (QT) exhibits good pharmacological activities for the treatment of liver diseases, including liver steatosis, fatty hepatitis, liver fibrosis, and liver cancer. It was selected as a model drug owing to its poor water solubility. QT NCs stabilized by GL (QT-NCs/GL) were fabricated by wet media milling technique and systemically evaluated. QT-NCs stabilized by poloxamer 188 (QT-NCs/P188) were prepared as a reference for comparison of in vitro and in vivo performance with QT-NCs/GL. QT-NCs/GL and QT-NCs/P188 with similar particle size around 130 nm were successfully fabricated by wet media milling technique. Both of QT-NCs/GL and QT-NCs/P188 showed irregular particles and short rods under SEM. XRPD revealed that QT-NCs/GL and QT-NCs/P188 remained in crystalline state with reduced crystallinity. QT-NCs/GL and QT-NCs/P188 exhibited significant solubility increase and drug release improvement of QT as compared to raw QT. No significant difference for the plasma concentration-time curves and pharmacokinetic parameters of QT were found following intravenous administration of QT-NCs/GL and QT-NCs/P188. However, a significantly higher liver distribution of QT following intravenous administration of QT-NCs/GL was observed in comparison to QT-NCs/P188, indicating QT-NCs stabilized by GL could achieve liver targeted delivery of QT. It could be concluded that GL used as stabilizer of QT NCs have a great potential for liver targeted drug delivery.

Enhanced Anti-Inflammatory Activity of Tilianin Based on the Novel Amorphous Nanocrystals

Tilianin (Til), a flavonoid glycoside, is well-known for its therapeutic promise in treating inflammatory disorders. Its poor water solubility and permeability limit its clinical applicability. In order to overcome these restrictions, an antisolvent precipitation and ultrasonication technique was used to prepare amorphous tilianin nanocrystals (Til NCs). We have adjusted the organic solvents, oil-to-water ratio, stabilizer composition, and ultrasonic power and time by combining single-factor and central composite design (CCD) methodologies. The features of Til NCs were characterized using powder X-ray diffraction (PXRD), scanning calorimetry (DSC), and transmission electron microscopy (TEM). Specifically, the optimized Til NCs were needle-like with a particle size ranging from 90 to 130 nm. PVA (0.3%, w/v) and TPGS (0.08%, w/v) stabilized them well. For at least two months, these Til NCs stayed amorphous and showed an impressive stability at 4 °C and 25 °C. Remarkably, Til NCs dissolved almost 20 times faster in simulated intestinal fluid (SIF) than they did in crude Til. In RAW264.7 cells, Til NCs also showed a better cellular absorption as well as safety and protective qualities. Til NCs were shown to drastically lower reactive oxygen species (ROS), TNF-α, IL-1β, and IL-6 in anti-inflammatory experiments, while increasing IL-10 levels and encouraging M1 macrophages to adopt the anti-inflammatory M2 phenotype. Our results highlight the potential of amorphous Til NCs as a viable approach to improve Til's anti-inflammatory effectiveness, solubility, and dissolving rate.

Innovative snail-mucus-extract (SME)-coated nanoparticles exhibit anti-inflammatory and anti-proliferative effects for potential skin cancer prevention and treatment

Nowadays, several studies have highlighted the ability of snail mucus in maintaining healthy skin conditions due to its emollient, regenerative and protective properties. In particular, mucus derived from H. aspersa muller has been reported to have beneficial effects such as antioxidant, antimicrobial activity and wound repair capacity. To enhance antioxidant activity of snail mucus, it was extracted in a hydroalcoholic solution and consequently freeze-dried. The obtained snail mucus extract (SME) was indeed endowed with higher antioxidant activity observed in cell-free models, however it was not possible to test its effects in cellular models as it creates a thick film on the cell surface. Therefore, in order to enhance beneficial effects of snail mucus and extend its potential use, SME was used to develop snail mucus extract-coated gold nanoparticles (AuNPs-SME) which exhibited anti-inflammatory properties on non-tumorigenic cells. LPS-induced inflammation in human NCTC keratinocytes was used as model to investigate the in vitro cytoprotective effects of nanoparticles. Co-treatment with LPS and AuNPs-SME significantly reduced pro-inflammatory cytokine transcription. Moreover, we demonstrated that AuNPs-SME not only can be used for anti-inflammatory treatments, but also as a sunscreen and antioxidant for potential cosmetic applications. Furthermore, AuNPs-SME's ability to selectively inhibit the growth of two human melanoma cell lines without affecting immortalized human keratinocyte viability in the same conditions was assessed. Thus, we demonstrated that snail mucus is suitable for creating innovative formulations and it can be considered a valid candidate for cosmeceutical applications to enrich the snail mucus based anti-age and sunscreen products already present on the market. Moreover, innovative formulations containing snail mucus can be potentially used for the treatment of specific skin neoplasms.

Intravenous nanocrystals: fabrication, solidification, in vivo fate, and applications for cancer therapy

INTRODUCTION

Intravenous nanocrystals (INCs) have shown intrinsic advantages in antitumor applications, particularly their properties of high drug loading, low toxicity, and controllable size. Therefore, it has a very bright application prospect as a drug delivery system.

AREAS COVERED

The ideal formulation design principles, fabrication, solidification, in vivo fate of INCs, the applications in drug delivery system (DDS) and the novel applications are covered in this review.

EXPERT OPINION

It is vital to select a suitable formulation and fabrication method to produce a stable and sterile INCs. Besides, the type of stabilizers and physical characteristics can also influence the in vivo fate of INCs, which is worthy of further studying. Based on wide researches about applications of INCs in cancer, biomimetic INCs are concerned increasingly for its favorable compatibility. The output of these studies suggested that INCs-based drug delivery could be a novel strategy for addressing the delivery of the drug that faces solubility, bioavailability, and toxicity problems.

Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects

INTRODUCTION

The fabrication of well-defined nanocrystals in size and form is the focus of much investigation. In this work, we have critically reviewed several recent instances from the literature that shows how the production procedure affects the physicochemical properties of the nanocrystals.

AREAS COVERED

Scopus, MedLine, PubMed, Web of Science, and Google Scholar were searched for peer-review articles published in the past few years using different key words. Authors chose relevant publications from their files for this review. This review focuses on the range of techniques available for producing nanocrystals. We draw attention to several recent instances demonstrating the impact of various process and formulation variables that affect the nanocrystals' physicochemical properties. Moreover, various developments in the characterization techniques explored for nanocrystals concerning their size, morphology, etc. have been discussed. Last but not least, recent applications, the effect of surface modifications, and the toxicological traits of nanocrystals have also been reviewed.

EXPERT OPINION

The selection of an appropriate production method for the formation of nanocrystals, together with a deep understanding of the relationship between the drug's physicochemical properties, unique features of the various formulation alternatives, and anticipated in-vivo performance, would significantly reduce the risk of failure during human clinical trials that are inadequate.

Cannabidiol for the Treatment of Brain Disorders: Therapeutic Potential and Routes of Administration

The use of cannabidiol (CBD) for treating brain disorders has gained increasing interest. While the mechanism of action of CBD in these conditions is still under investigation, CBD has been shown to affect numerous different drug targets in the brain that are involved in brain disorders. Here we review the preclinical and clinical evidence on the potential therapeutic use of CBD in treating various brain disorders. Moreover, we also examine various drug delivery approaches that have been applied to CBD. Due to the slow absorption and low bioavailability with the current oral CBD therapy, more efficient routes of administration to bypass hepatic metabolism, particularly pulmonary delivery, should be considered. Comparison of pharmacokinetic studies of different delivery routes highlight the advantages of intranasal and inhalation drug delivery over other routes of administration (oral, injection, sublingual, buccal, and transdermal) for treating brain disorders. These two routes of delivery, being non-invasive and able to achieve fast absorption and increase bioavailability, are attracting increasing interest for CBD applications, with more research and development expected in the near future.

Fighting Epilepsy with Nanomedicines-Is This the Right Weapon?

Epilepsy is a chronic and complex condition and is one of the most common neurological diseases, affecting about 50 million people worldwide. Pharmacological therapy has been, and is likely to remain, the main treatment approach for this disease. Although a large number of new antiseizure drugs (ASDs) has been introduced into the market in the last few years, many patients suffer from uncontrolled seizures, demanding the development of more effective therapies. Nanomedicines have emerged as a promising approach to deliver drugs to the brain, potentiating their therapeutic index. Moreover, nanomedicine has applied the knowledge of nanoscience, not only in disease treatment but also in prevention and diagnosis. In the current review, the general features and therapeutic management of epilepsy will be addressed, as well as the main barriers to overcome to obtain better antiseizure therapies. Furthermore, the role of nanomedicines as a valuable tool to selectively deliver drugs will be discussed, considering the ability of nanocarriers to deal with the less favourable physical-chemical properties of some ASDs, enhance their brain penetration, reduce the adverse effects, and circumvent the concerning drug resistance.

In vitro Evaluation of Paliperidone Palmitate Loaded Cubosomes Effective for Nasal-to-Brain Delivery

Introduction

This work aimed to develop chitosan-coated cubosomal nanoparticles intended for nose-to-brain delivery of paliperidone palmitate. They were compared with standard and cationic cubosomal nanoparticles. This comparison relies on numerous classical in vitro tests and powder deposition within a 3D-printed nasal cast.

Methods

Cubosomal nanoparticles were prepared by a Bottom-up method followed by a spray drying process. We evaluated their particle size, polydispersity index, zeta-potential, encapsulation efficiency, drug loading, mucoaffinity properties and morphology. The RPMI 2650 cell line was used to assess the cytotoxicity and cellular permeation. An in vitro deposition test within a nasal cast completed these measurements.

Results

The selected chitosan-coated cubosomal nanoparticles loaded with paliperidone palmitate had a size of 305.7 ± 22.54 nm, their polydispersity index was 0.166 ± 0.022 and their zeta potential was +42.4 ± 0.2 mV. This formulation had a drug loading of 70% and an encapsulation efficiency of 99.7 ± 0.1%. Its affinity with mucins was characterized by a ΔZP of 20.93 ± 0.31. Its apparent permeability coefficient thought the RPMI 2650 cell line was 3.00E-05 ± 0.24E-05 cm/s. After instillation in a 3D-printed nasal cast, the fraction of the injected powder deposited in the olfactory region reached 51.47 ± 9.30% in the right nostril and 41.20 ± 4.59% in the left nostril, respectively.

Conclusion

The chitosan coated cubosomal formulation seems to be the most promising formulation for nose-to-brain delivery. Indeed, it has a high mucoaffinity and a significantly higher apparent permeability coefficient than the two other formulations. Finally, it reaches well the olfactory region.

Preparation of PLGA Nanoparticles by Milling Spongelike PLGA Microspheres

Currently, emulsification-templated nanoencapsulation techniques (e.g., nanoprecipitation) have been most frequently used to prepare poly-d,l-lactide-co-glycolide (PLGA) nanoparticles. This study aimed to explore a new top-down process to produce PLGA nanoparticles. The fundamental strategy was to prepare spongelike PLGA microspheres with a highly porous texture and then crush them into submicron-sized particles via wet milling. Therefore, an ethyl formate-based ammonolysis method was developed to encapsulate progesterone into porous PLGA microspheres. Compared to a conventional solvent evaporation process, the ammonolysis technique helped reduce the tendency of drug crystallization and improved drug encapsulation efficiency accordingly (solvent evaporation, 27.6 ± 4.6%; ammonolysis, 65.1 ± 1.7%). Wet milling was performed on the highly porous microspheres with a D₅₀ of 64.8 μm under various milling conditions. The size of the grinding medium was the most crucial factor for our wet milling. Milling using smaller zirconium oxide beads (0.3~1 mm) was simply ineffective. However, when larger beads with diameters of 3 and 5 mm were used, our porous microspheres were ground into submicron-sized particles. The quality of the resultant PLGA nanoparticles was demonstrated by size distribution measurement and field emission scanning electron microscopy. The present top-down process that contrasts with conventional bottom-up approaches might find application in manufacturing drug-loaded PLGA nanoparticles.

Nanocrytals-Mediated Oral Drug Delivery: Enhanced Bioavailability of Amiodarone

The aim of this study was to improve the saturation solubility, dissolution profile and oral bioavailability of amiodarone hydrochloride (AMH), a highly lipophilic drug. Stabilizer (Pluronic F-127)-coated AMH nanocrystals (AMH-NCs) were developed by a combination of antisolvent precipitation and homogenization techniques. The optimized formulation comprised pluronic F-127 and AMH at the concentration of 4% and 2% w/v, respectively. The particle size (PS), zeta potential (ZP) and polydispersity index (PDI) of the optimized formulation was found to be 221 ± 1.2 nm, 35.3 mV and 0.333, respectively. The optimized formulation exhibited a rough surface morphology with particles in colloidal dimensions and a significant reduction in crystallinity of the drug. AMH-NCs showed a marked increase in the saturation solubility as well as rapid dissolution rate when compared with the AMH and marketed product. The stability study displayed that the formulation was stable for 3 months, with no significant change in the PS, ZP and PDI. The in vivo pharmacokinetic study demonstrated the ability of AMH-NCs to significantly (p < 0.05) improve the oral bioavailability (2.1-fold) of AMH in comparison with AMH solution, indicating that the production of AMH-NCs using a combination of antisolvent precipitation and homogenization techniques could enhance the bioavailability of the drug.