Preparation of Nanocrystals for Insoluble Drugs by Top-Down Nanotechnology with Improved Solubility and Bioavailability

Physicochemical properties and in vitro release of formononetin nano-particles by ultrasonic probe-assisted precipitation in four polar organic solvents

Although formononetin has a considerable biological activity, its therapeutic use is limited by its low solubility. Formononetin was dissolved in ethanol, methanol, N, N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) in this investigation, the antisolvent precipitation procedure with the assistance of an external ultrasonic probe was used to manufacture the formononetin nano-particles. The ideal parameters for response surface BBD optimization are as follows: feed volume flow rate of 6 mL/min; ultrasonic power of 860 W; and liquid-liquid ratio of 1:12.5. The formononetin nano-particles have a smaller particle diameter than raw sample; the lowest size can be as small as (329 ± 1.99) nm, which is 45 times smaller than raw. An in vitro digestion test using a solution that simulated intestinal solution revealed that the release rate of the nano-particle was 1.75 times than that of the raw formononetin. The formononetin nano-particles generated by the aforementioned four solvents have the following order of diameter: ethanol > methanol > DMF > DMSO. This study provided a technical reference for the functional food components in deep processing.

Pharmaceutical Nanoparticles Formation and Their Physico-Chemical and Biomedical Properties

The use of medicinal substances in nanosized forms (nanoforms, nanoparticles) allows the therapeutic effectiveness of pharmaceutical preparations to be increased due to several factors: (1) the high specific surface area of nanomaterials, and (2) the high concentration of surface-active centers interacting with biological objects. In the case of drug nanoforms, even low concentrations of a bioactive substance can have a significant therapeutic effect on living organisms. These effects allow pharmacists to use lower doses of active components, consequently lowering the toxic side effects of pharmaceutical nanoform preparations. It is known that many drug substances that are currently in development are poorly soluble in water, so they have insufficient bioavailability. Converting them into nanoforms will increase their rate of dissolution, and the increased saturation solubility of drug nanocrystals also makes a significant contribution to their high therapeutic efficiency. Some physical and chemical methods can contribute to the formation of both pure drug nanoparticles and their ligand or of polymer-covered nanoforms, which are characterized by higher stability. This review describes the most commonly used methods for the preparation of nanoforms (nanoparticles) of different medicinal substances, paying close attention to modern supercritical and cryogenic technologies and the advantages and disadvantages of the described methods and techniques; moreover, the improvements in the physico-chemical and biomedical properties of the obtained medicinal nanoforms are also discussed.

Resveratrol nanocrystals based dissolving microneedles with highly efficient for rheumatoid arthritis

Rheumatoid arthritis (RA) is a common immune disease characterized mainly by erosive arthritis with extensive clinical sequelae. Resveratrol (Res) has pharmacological effects in the treatment of RA, but it has not been widely used in the clinic due to its poor water solubility and low bioavailability. In this study, a drug delivery system (Res-NC MNs) of dissolved microneedles (MNs) loaded with Res nanocrystals (NC) was designed for the treatment of RA. Res-NC MNs can improve the drawbacks of long-term oral drug delivery with toxic side effects and low compliance associated with intra-articular drug delivery. In this study, Res-NC was prepared by media milling and loaded into soluble microneedles prepared from hyaluronic acid (HA) by vacuum casting for the treatment of RA. HA has high mechanical strength and can penetrate the cuticle layer of the skin for effective drug delivery. In in vivo pharmacodynamic experiments, Res-NC MNs achieved better therapeutic efficacy in the treatment of RA compared with oral Res. These findings suggest that Res-NC MNs may be an effective and promising drug delivery strategy for the treatment of RA.

Novel tetrahydrocurcumin integrated mucoadhesive nanocomposite κ-carrageenan/xanthan gum sponges: a strategy for effective local treatment of oral cancerous and precancerous lesions

Oral cancer is one of the leading causes of death worldwide. Oral precancerous lesions (OPL) are the precursors of oral cancer, with varying degrees of progression. Tetrahydrocurcumin (THC) is a major metabolite of curcumin with superior anticancer properties against various types of cancer. However, THC's clinical outcome is limited by its poor aqueous solubility. Herein, we developed novel mucoadhesive biopolymer-based composite sponges for buccal delivery of THC, exploiting nanotechnology and mucoadhesion for efficient prevention and treatment of oral cancer. Firstly, THC-nanocrystals (THC-NC) were formulated and characterized for subsequent loading into mucoadhesive composite sponges. The anticancer activity of THC-NC was assessed on a human tongue squamous carcinoma cell line (SCC-4). Finally, the chemopreventive activity of THC-NC loaded sponges (THC-NC-S) was examined in DMBA-induced hamster OPL. The selected THC-NC exhibited a particle size of 532.68 ± 13.20 nm and a zeta potential of -46.08 ± 1.12 mV. Moreover, THC-NC enhanced the anticancer effect against SCC-4 with an IC50 value of 80 µg/mL. THC-NC-S exhibited good mucoadhesion properties (0.24 ± 0.02 N) with sustained drug release, where 90% of THC was released over 4 days. Furthermore, THC-NC-S had a magnificent potential for maintaining high chemopreventive activity, as demonstrated by significant regression in the dysplasia degree and a decline in cyclin D1 (control: 40.4 ± 12.5, THC-NC-S: 12.07 ± 5.2), culminating in significant amelioration after 25 days of treatment. Conclusively, novel THC-NC-S represent a promising platform for local therapy of OPL, preventing their malignant transformation into cancer.

Combined Silver Sulfadiazine Nanosuspension with Thermosensitive Hydrogel: An Effective Antibacterial Treatment for Wound Healing in an Animal Model

Introduction

Silver sulfadiazine (AgSD) is widely used in burn wound treatment due to its broad-spectrum antibacterial activity. However, its application in wound healing is greatly hindered by the low solubility of AgSD particles and their cellular cytotoxicity. Herein, we studied the safety and in vivo efficacy of nano-sized silver sulfadiazine loaded in poloxamer thermosensitive hydrogel (NS/Gel).

Methods

In NS/Gel, silver sulfadiazine was prepared into silver sulfadiazine nanosuspension (NS) to improve the solubility and enhance its antibacterial activity, whereas the poloxamer thermosensitive hydrogel was selected as a drug carrier of NS to achieve slow drug release and reduced cytotoxicity. The acute toxicity of silver sulfadiazine nanosuspension was first evaluated in healthy mice, and its median lethal dose (LD₅₀) was calculated by the modified Karber method. Furthermore, in vivo antibacterial effect and wound healing property of NS/Gel were evaluated on the infected deep second-degree burn wound mice model.

Results

The mortality ratio of mice was concentration-dependent, and the LD₅₀ for silver sulfadiazine nanosuspension was estimated to be 252.1 mg/kg (230.8 to 275.4 mg/kg, 95% confidence limit). The in vivo dosages used for burn wound treatment (40-50 mg/kg) were far below LD₅₀ (252.1 mg/kg). NS/Gel significantly accelerated wound healing in the deep second wound infection mice model, achieving > 85% wound contraction on day 14. Staphylococcus aureus in the wound region was eradicated after 7 days in NS/Gel group, while the bacterial colony count was still measurable in the control group. Histological analysis and cytokines measurement confirmed that the mice treated with NS/Gel exhibited well-organized epithelium and multiple keratinized cell layers compared to control groups with the modulated expression of IL-6, VEGF, and TGF-β.

Conclusion

The combination of silver sulfadiazine nanosuspension and thermo-responsive hydrogel has great potential in clinical burn wound treatment.

Elaborating the crystal transformation referenced microhydrodynamic model and fracture mechanism combined molecular modelling of irbesartan nanosuspensions formation in wet media milling

In recent years, polymorphic transformation involved in media milling has become a key factor in inducing the instability of nanosuspensions (NSs). The variation trend of microhydrodynamic parameters, including milling intensity factor (F), can be observed under different milling conditions. Therefore, this study first referenced the microhydrodynamic model to explore how formulations and process parameters affect Irbesartan (IRB) form A crystallinity during wet media milling. As a result, the crystallinity of form A was affected by the intermolecular interactions between drug particles and stabilizers. The crystallinity of form A decreased with decreasing drug loading, increasing stirrer speed and bead loading, which depended on the role of F. Milling could promote the transformation from a 1H to 2H tetrazole ring with stabilizers containing -OH, and form B was changed to form A and finally to an amorphous state. Molecular modelling shows that forms A and B are ductile and fragile materials, respectively, and both present anisotropy. When milling beads hit both polymorphs paralleling to the (010) surface, the bead-bead collisions are more helpful in fracturing IRB particles. The results of this study may provide a foundation for controlling crystal transformation and obtaining ideal crystal forms.

Preparation and optimization of surface stabilized cryptotanshinone nanocrystals with enhanced bioavailability

Cryptotanshinone (CTS) is a plant product extracted from Salvia miltiorrhiza Bunge with various pharmacological significances. In addition to its activities against coronary heart disease, hyperlipidemia, stroke, hepatitis and chronic renal failure, it demonstrates antimetastatic effects. However, its clinical use is limited due to its poor aqueous solubility and oral bioavailability. Herein, CTS nanocrystals were prepared with the precipitation method followed by high-pressure homogenization using Poloxamer 407 as the stabilizer. A stable product was further obtained by lyophilization. The particle size of the CTS nanocrystals was 315.67 ± 11.02 nm, and the zeta potential was near 0 mV. The crystallinity was confirmed by DSC and PXRD. The saturation solubility was substantially increased from 0.97 ± 0.12 μg/ml to 62.29 ± 1.91 μg/ml, and the dissolution rate was also significantly accelerated. A pharmacokinetic study in rats revealed an improvement in oral bioavailability (2.87-fold) with CTS nanocrystals compared to the raw drug. In conclusion, the results of this study suggest a feasible formulation for the oral delivery of CTS.

Baicalin-berberine complex nanocrystals orally promote the co-absorption of two components

Baicalin (BA)-berberine (BBR) have been proposed as the couple in the prevention and treatment of numerous diseases due to their multiple functional attributes. However, with regard to certain factors involving unsatisfactory aqueous solubility and low bioavailability associated with its clinical application, there is need for continuous researches by scientist. In this study, after successfully preparing BA-BBR complex, BA-BBR complex nanocrystals were obtained through high-pressure homogenization and evaluated (in vitro and in vivo). The particle size, distribution, morphology, and crystalline properties for the optimal BA-BBR complex nanocrystals were characterized by the use of scanning electron microscope, dynamic light scattering, powder X-ray diffraction, and differential scanning calorimetry. The particle size and poly-dispersity index of BA-BBR complex nanocrystals were 318.40 ± 3.32 nm and 0.26 ± 0.03, respectively. In addition, evaluation of the in vitro dissolution extent indicated that BA and BBR in BA-BBR complex nanocrystals were 3.30- and 2.35-fold than BA-BBR complex. Subsequently, single-pass intestinal perfusion combined with microdialysis test and oral pharmacokinetics in SD rats was employed to evaluate the in vivo absorption improvement of BA-BBR complex nanocrystals. The pharmacokinetics results exhibited that the area under curve of BA and BBR in the BA-BBR complex nanocrystals group were 622.65 ± 456.95 h·ng/ml and 167.28 ± 78.87 h·ng/ml, respectively, which were separately 7.49- and 2.64-fold than the complex coarse suspension. In conclusion, the above results indicate that the developed and optimized BA-BBR complex nanocrystals could improve the dissolution rate and extent and oral bioavailability, as well as facilitate the co-absorption of the drug prescriptions BA and BBR.

Exploring the influence factors and improvement strategies of drug polymorphic transformation combined kinetic and thermodynamic perspectives during the formation of nanosuspensions

Nanosuspensions can effectively increase saturation solubility and improve the bioavailability of poorly water-soluble drugs attributed to high loading and surface-to-volume ratio. Wet media milling has been regarded as a scalable method to prepare nanosuspensions because of its simple operation and easy scale-up. In recent years, besides particle aggregation and Ostwald ripening, polymorphic transformation induced by processing has become a critical factor leading to the instability of nanosuspensions. Therefore, this review aims to discuss the influence factors comprehensively and put forward the corresponding improvement strategies of polymorphic transformation during the formation of nanosuspensions. In addition, this review also demonstrates the implication of molecular simulation in polymorphic transformation. The competition between shear-induced amorphization and thermally activated crystallization is the global mechanism of polymorphic transformation during media milling. The factors affecting the polymorphic transformation and corresponding improvement strategies are summarized from formulation and process parameters perspectives during the formation of nanosuspensions. The development of analytical techniques has promoted the qualitative and quantitative characterization of polymorphic transformation, and some techniques can in-situ monitor dynamic transformation. The microhydrodynamic model can be referenced to study the stress intensities by analyzing formulation and process parameters during wet media milling. Molecular simulation can be used to explore the possible polymorphic transformation based on the crystal structure and energy. This review is helpful to improve the stability of nanosuspensions by regulating polymorphic transformation, providing quality assurance for nanosuspension-based products.

Preparation of ICA-loaded mPEG-ICA nanoparticles and their application in the treatment of LPS-induced H9c2 cell damage

Hydrophilic polyethylene glycol monomethyl ether (mPEG) was grafted onto Icariin (ICA) by succinic anhydride to form a polyethylene glycol-Icariin (mPEG-ICA) polymer. The structure of the polymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). mPEG-ICA nanoparticles loaded with ICA were prepared by physical embedding of ICA by dialysis. The particle size was determined to be (220 ± 13.7) nm, and the ζ potential was (2.30 ± 1.33) mV by dynamic light scattering (DLS). Under a transmission electron microscope (TEM), the nanoparticles were spherical, and the morphology was regular. In the medium with pH 7.4, the drug release rate of mPEG-ICA nanoparticles reached (52.80 ± 1.70)% within 72 h. At pH 6.8, the cumulative drug release of nanoparticles reached (75.66 ± 0.17)% within 48 h. Treatment of the nanoparticles with LPS-treated H9c2 cells maintained cell viability, reduced LDH release and exerted antiapoptotic effects. Moreover, ICA-loaded mPEG-ICA nanoparticles significantly decreased the mRNA expression of the myocardial inflammatory cytokines TNF-α, IL-1β and IL-6M. In conclusion, ICA-loaded mPEG-ICA nanoparticles protected against LPS-induced H9c2 cell injury.

Lipid-based nanoparticles for psoriasis treatment: a review on conventional treatments, recent works, and future prospects

Psoriasis is a lingering inflammatory skin disease that attacks the immune system. The abnormal interactions between T cells, immune cells, and inflammatory cytokines causing the epidermal thickening. International guidelines have recommended topical treatments for mild to moderate psoriasis whilst systemic and phototherapy treatments for moderate to severe psoriasis. However, current therapeutic approaches have a wider extent to treat moderate to severe type of psoriasis especially since the emergence of diverse biologic agents. In the meantime, topical delivery of conventional treatments has prompted many unsatisfactory effects to penetrate through the skin (stratum corneum). By understanding the physiology of stratum corneum barrier functions, scientists have developed different types of lipid-based nanoparticles like solid lipid nanoparticles, nanostructured lipid carriers, nanovesicles, and nanoemulsions. These novel drug delivery systems help the poorly solubilised active pharmaceutical ingredient reaches the targeted site seamlessly because of the bioavailability feature of the nanosized molecules. Lipid-based nanoparticles for psoriasis treatments create a paradigm for topical drug delivery due to their lipids' amphiphilic feature to efficiently encapsulate both lipophilic and hydrophilic drugs. This review highlights different types of lipid-based nanoparticles and their recent works of nano formulated psoriasis treatments. The encapsulation of psoriasis drugs through lipid nanocarriers unfold numerous research opportunities in pharmaceutical applications but also draw challenges for the future development of nano drugs.

Preparation, optimization, and evaluation of midazolam nanosuspension: enhanced bioavailability for buccal administration

Midazolam is considered as one of the best first-line drugs in managing status epilepticus in children who require emergency drug treatment. Due to poor water solubility, oral bioavailability of midazolam is relatively low. To improve its dissolution and absorption, midazolam nano-suspensions were formulated with different stabilizers using the ultrasonic technique. A combination of Tween 80 and Poloxamer (TP) was considered as one stabilizer and 3-methyl chitosan (TMC) as another stabilizer. The ratio of the stabilizers was selected as an independent variable, and their effects on the particle size and the zeta potential were evaluated by the simplex lattice mixture method. The freeze-dried optimized midazolam nano-suspension powder was characterized by particle-size analysis, SEM, the stability test, and the dissolution test. The optimized midazolam nano-suspension (containing 76% TMC and 24% TP) had a mean particle size of 197 ± 7 nm and a zeta potential of 31 ± 4 (mV). The stability test showed that the midazolam nano-suspension is stable for 12 months. In the in vitro dissolution test, the midazolam nano-suspension showed a marked increase in the drug dissolution percentage versus coarse midazolam. In the in vivo evaluation, the midazolam nano-suspension exhibited a significant increase in the C_max and the AUC_0-5, and a major decrease in T_max. The overall results indicate the nano-suspension of midazolam is a promising candidate for managing status epilepticus in children in emergency situation.

Inclusion Complex of Docetaxel with Sulfobutyl Ether β-Cyclodextrin: Preparation, In Vitro Cytotoxicity and In Vivo Safety

Docetaxel (DTX), as a first-line anti-tumor drug, has been studied for decades for its diverse bioactivities. However, DTX presents poor solubility in water, low bioavailability and serious toxic side effects which has hindered its application in the clinic. To address these problems, docetaxel-sulfobutyl ether-β-cyclodextrin inclusion complex (DTX-SBE-β-CD) was prepared successfully by saturated aqueous solution method. Sulfobutyl ether β-cyclodetrin (SBE-β-CD) is used as delivery material. For this study, the inclusion complex of docetaxel with sulfobutyl ether β-cyclodetrin (DTX-SBE-β-CD) was prepared and optimized its properties to enhance the cytotoxicity of cancer cells. A large number of physical characterization results showed that DTX-SBE-β-CD inclusion complex was successfully prepared by saturated aqueous solution method. DTX-SBE-β-CD inclusion complex was optimized by Central Composite Design. DTX-SBE-β-CD had an inhibitory effect on the in vitro determination of MCF-7 and HepG2 cells by MTT assay. Pharmacokinetic studies were carried out on male Sprague–Dawley rats by tail injection, including the distribution, metabolism and elimination of DTX-SBE-β-CD in vivo. In the experimental study of inhibition of cancer cells, DTX and DTX-SBE-β-CD showed apparent concentration-dependent inhibitory actions on tumor cells and the inhibition of DTX-SBE-β-CD group was more obvious.