Nanosizing of a drug/carrageenan complex to increase solubility and dissolution rate

Designing network structure hydrogels derived from carrageenan- phosphated polymers by covalent and supramolecular interactions for potential biomedical applications

Recently, various efforts have been made to explore the potential of natural polysaccharides derived from sea weeds to promote sustainable development. Herein, carrageenan (CG), a polysaccharide extracted from red sea algae, was utilized to design network structures as hydrogels, aimed at significant applications in drug delivery (DD) systems. Hydrogels were designed by graft copolymerization reaction of poly(bis [2-methacryloyloxy] ethyl phosphate [poly(BMEP)] and poly(acrylic acid) [poly(AAc)] onto CG in the presence of a crosslinking agent. Hydrogels were developed by covalent linkage by graft copolymerization and supramolecular interactions, existing in the copolymers. Copolymers were characterized by Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), and X-ray diffraction (XRD) instrumentations. The drug diffusion exhibited a sustained pattern due to polymer-drug interactions. The drug release followed non-Fickian diffusion mechanism and the release profile was most accurately depicted by first order kinetic model. The biocompatible nature of the copolymer was demonstrated from the hemolytic index value signifying minimal adverse interactions with blood component upon exposure. A protein adsorption test was performed using bovine serum albumin (BSA), exhibiting 8.15 ± 0.26 % albumin adsorption. Polymers exhibited mucoadhesive character, evidenced by their requirement of a detachment force measuring 195 ± 4.72 mN for separation from the membrane during interactions with the mucosal surface. The hydrogels exhibited antioxidant properties, evidenced by 2, 2'-Diphenylpicrylhydrazyl (DPPH) assay, revealing copolymer capable of scavenging 58.21 ± 2.26 % of free radical. The hydrogel revealed antimicrobial activity against P. aeruginosa and S. aureus bacteria, a property further enhanced in hydrogels with the drug doxycycline. These findings suggest suitability of these hydrogels for biomedical applications, with a significant emphasis on drug delivery.

Structure and drug delivery relationship of acidic polysaccharides: A review

Scientists from across the world are being inspired by recent development in polysaccharides and their use in medical administration. Due to their extraordinary physical, chemical, and biological characteristics, polysaccharides are excellent materials for use in medicine. Acidic polysaccharides, which include Pectin, Xanthan gum, Carrageenan, Alginate, and Glycosaminoglycan, are natural polymers with carboxyl groups that are being researched for their potential as drug delivery systems. Most publications do not discuss how the different polysaccharides interact structurally in terms of drug delivery, which limits the scope of their use. The purpose of this review is to inform readers about the structural activity correlations between acidic polysaccharides, their different modification process and effects of combination of various acidic polysaccharides which have been used in drug delivery systems and expanding their potential applications, and bringing new perspectives to the fore.

Progress in the development of stabilization strategies for nanocrystal preparations

In recent years, nanocrystal technology has been extensively investigated. Due to the submicron particle size and unique physicochemical properties of nanocrystals, they overcome the problems of low drug solubility and poor bioavailability. Although the structures of nanocrystals are simple, the further development of these materials is hindered by their stability. Drug nanocrystals with particle sizes of 1∼1000 nm usually require the addition of stabilizers such as polymers or surfactants to enhance their stability. The stability of nanocrystal suspensions and the redispersibility of solid nanocrystal drugs are the key factors for the large-scale production of nanocrystal preparations. In this paper, the factors that affect the stability of drug nanocrystal preparations are discussed, and related methods for solving the stability problem are put forward.

Electrohydrodynamic atomisation driven design and engineering of opportunistic particulate systems for applications in drug delivery, therapeutics and pharmaceutics

Electrohydrodynamic atomisation (EHDA) technologies have evolved significantly over the past decade; branching into several established and emerging healthcare remits through timely advances in the engineering sciences and tailored conceptual process designs. More specifically for pharmaceutical and drug delivery spheres, electrospraying (ES) has presented itself as a high value technique enabling a plethora of different particulate structures. However, when coupled with novel formulations (e.g. co-flows) and innovative device aspects (e.g., materials and dimensions), core characteristics of particulates are manipulated and engineered specifically to deliver an application driven need, which is currently lacking, ranging from imaging and targeted delivery to controlled release and sensing. This demonstrates the holistic nature of these emerging technologies; which is often overlooked. Parametric driven control during particle engineering via the ES method yields opportunistic properties when compared to conventional methods, albeit at ambient conditions (e.g., temperature and pressure), making this extremely valuable for sensitive biologics and molecules of interest. Furthermore, several processing (e.g., flow rate, applied voltage and working distance) and solution (e.g., polymer concentration, electrical conductivity and surface tension) parameters impact ES modes and greatly influence the production of resulting particles. The formation of a steady cone-jet and subsequent atomisation during ES fabricates particles demonstrating monodispersity (or near monodispersed), narrow particle size distributions and smooth or textured morphologies; all of which are successfully incorporated in a one-step process. By following a controlled ES regime, tailored particles with various intricate structures (hollow microspheres, nanocups, Janus and cell-mimicking nanoparticles) can also be engineered through process head modifications central to the ES technique (single-needle spraying, coaxial, multi-needle and needleless approaches). Thus, intricate formulation design, set-up and combinatorial engineering of the EHDA process delivers particulate structures with a multitude of applications in tissue engineering, theranostics, bioresponsive systems as well as drug dosage forms for specific delivery to diseased or target tissues. This advanced technology has great potential to be implemented commercially, particularly on the industrial scale for several unmet pharmaceutical and medical challenges and needs. This review focuses on key seminal developments, ending with future perspectives addressing obstacles that need to be addressed for future advancement.

Preparation of Curcumin-Eudragit® E PO Solid Dispersions with Gradient Temperature through Hot-Melt Extrusion

Hot-melt extrusion (HME) has great advantages for the preparation of solid dispersion (SD), for instance, it does not require any organic solvents. Nevertheless, its application to high-melting-point and thermosensitive drugs has been rarely reported. In this study, thermally unstable curcumin (Cur) was used as a drug model. The HME process was systematically studied by adjusting the gradient temperature mode and residence time, with the content, crystallinity and dissolution of Cur as the investigated factors. The effects of barrel temperature, screw speed and cooling rate on HME were also examined. Solubility parameters and the Flory-Huggins method were used to evaluate the miscibility between Cur and carriers. Differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, equilibrium solubility and in vitro and in vivo experiments were used to characterize and evaluate the results. An amorphous Cur SD was successfully obtained, increasing the solubility and release of Cur. In the optimal process, the mass ratio of Cur to Eudragit® E PO (EPO) was 1:4 and the barrel temperature was set at a gradient heating mode (130 °C-135 °C-140 °C-145 °C-150 °C-155 °C-160 °C) at 100 rpm. Related pharmacokinetic test results also showed the improved bioavailability of the drug in rats. In a pharmacodynamic analysis of Sprague-Dawley rats, the Cmax and the bioavailability of the Cur-EPO SD were 2.6 and 1.5 times higher than those of Cur, respectively. The preparation of the amorphous SD not only provided more solubility but also improved the bioavailability of Cur, which provides an effective way to improve the bioavailability of BCS II drugs.

Formulation Development of a Food-Graded Curcumin-Loaded Medium Chain Triglycerides-Encapsulated Kappa Carrageenan (CUR-MCT-KC) Gel Bead Based Oral Delivery Formulation

In recent years, curcumin has been a major research endeavor in food and biopharmaceutical industries owing to its miscellaneous health benefits. There is an increasing amount of research ongoing in the development of an ideal curcumin delivery system to resolve its limitations and further enhance its solubility, bioavailability and bioactivity. The emergence of food-graded materials and natural polymers has elicited new research interests into enhanced pharmaceutical delivery due to their unique properties as delivery carriers. The current study is to develop a natural and food-graded drug carrier with food-derived MCT oil and a seaweed-extracted polymer called k-carrageenan for oral delivery of curcumin with improved solubility, high gastric resistance, and high encapsulation of curcumin. The application of k-carrageenan as a structuring agent that gelatinizes o/w emulsion is rarely reported and there is so far no MCT-KC system established for the delivery of hydrophobic/lipophilic molecules. This article reports the synthesis and a series of in vitro bio-physicochemical studies to examine the performance of CUR-MCT-KC as an oral delivery system. The solubility of CUR was increased significantly using MCT with a good encapsulation efficiency of 73.98 ± 1.57% and a loading capacity of 1.32 ± 0.03 mg CUR/mL MCT. CUR was successfully loaded in MCT-KC, which was confirmed using FTIR and SEM with good storage and thermal stability. Dissolution study indicated that the solubility of CUR was enhanced two-fold using heated MCT oil as compared to naked or unformulated CUR. In vitro release study revealed that encapsulated CUR was protected from premature burst under simulated gastric environment and released drastically in simulated intestinal condition. The CUR release was active at intestinal pH with the cumulative release of >90% CUR after 5 h incubation, which is the desired outcome for CUR absorption under human intestinal conditions. A similar release profile was also obtained when CUR was replaced with beta-carotene molecules. Hence, the reported findings demonstrate the potencies of MCT-KC as a promising delivery carrier for hydrophobic candidates such as CUR.

Improvement of antithrombotic activity of red ginseng extract by nanoencapsulation using chitosan and antithrombotic cross-linkers: polyglutamic acid and fucodian

Background

Red ginseng (RG) extract, especially ginsenoside Rg1 and Rb1 fractions has been reported to have antithrombotic activities. However, gastric instability and low intestinal permeability are considered to be obstacles to its oral administration. We hypothesized that stability, permeability, and activities of RG might be improved by encapsulation within nanoparticles (NPs) prepared with antithrombotic coating materials.

Methods

RG-loaded chitosan (CS) NPs (PF-NPs) were prepared by complex ionic gelation with the antithrombotic wall materials, polyglutamic acid (PGA), and fucoidan (Fu). The concentrations of PGA (mg/mL, X₁) and Fu (mg/mL, X₂) were optimized for the smallest particle size by response surface methodology. Antithrombotic activities of RG and PF-NPs were analyzed using ex vivo and in vivo antiplatelet activities, in vivo carrageenan-induced mouse tail, and arteriovenous shunt rat thrombosis models.

Results

In accordance with a quadratic regression model, the smallest PF-NPs (286 ± 36.6 nm) were fabricated at 0.628 mg/mL PGA and 0.081 mg/mL Fu. The inhibitory activities of RG on ex vivo and in vivo platelet aggregation and thrombosis in in vivo arteriovenous shunt significantly (p < 0.05) increased to approximately 66.82%, 35.42%, and 38.95%, respectively, by encapsulation within PF-NPs. For an in vivo carrageenan-induced mouse tail thrombosis model, though RG had a weaker inhibitory effect, PF-NPs reduced thrombus significantly due to the presence of PGA and Fu.

Conclusion

PF-NPs contributed to improve the activities of RG not only by nanoencapsulation but also by antithrombotic coating materials. Therefore, PG-NPs can be suggested as an efficient delivery system for oral administration of RG.

Smart Carriers and Nanohealers: A Nanomedical Insight on Natural Polymers

Biodegradable polymers are popularly being used in an increasing number of fields in the past few decades. The popularity and favorability of these materials are due to their remarkable properties, enabling a wide range of applications and market requirements to be met. Polymer biodegradable systems are a promising arena of research for targeted and site-specific controlled drug delivery, for developing artificial limbs, 3D porous scaffolds for cellular regeneration or tissue engineering and biosensing applications. Several natural polymers have been identified, blended, functionalized and applied for designing nanoscaffolds and drug carriers as a prerequisite for enumerable bionano technological applications. Apart from these, natural polymers have been well studied and are widely used in material science and industrial fields. The present review explains the prominent features of commonly used natural polymers (polysaccharides and proteins) in various nanomedical applications and reveals the current status of the polymer research in bionanotechnology and science sectors.

Enhanced solubility of piperine using hydrophilic carrier-based potent solid dispersion systems

CONTEXT

Piperine alkaloid, an important constituent of black pepper, exhibits numerous therapeutic properties, whereas its usage as a drug is limited due to its poor solubility in aqueous medium, which leads to poor bioavailability.

OBJECTIVE

Herein, a new method has been developed to improve the solubility of this drug based on the development of solid dispersions with improved dissolution rate using hydrophilic carriers such as sorbitol (Sor), polyethylene glycol (PEG) and polyvinyl pyrrolidone K30 (PVP) by solvent method. Physical mixtures of piperine and carriers were also prepared for comparison.

METHODS

The physicochemical properties of the prepared solid dispersions were examined using SEM, TEM, DSC, XRD and FT-IR. In vitro dissolution profile of the solid dispersions was recorded and compared with that of the pure piperine and physical mixtures. The effect of these carriers on the aqueous solubility of piperine has been investigated.

RESULTS

The solid dispersions of piperine with Sor, PEG and PVP exhibited superior performance for the dissolution of piperine with a drug release of 70%, 76% and 89%, respectively after 2 h compared to physical mixtures and pure piperine, which could be due to its transformation from crystalline to amorphous form as well as the attachment of hydrophilic carriers to the surface of poorly water-soluble piperine.

CONCLUSION

Results suggest that the piperine solid dispersions prepared with improved in vitro release exhibit potential advantage in delivering poorly water-soluble piperine as an oral supplement.

Fabrication and in vitro/in vivo evaluation of amorphous andrographolide nanosuspensions stabilized by d-α-tocopheryl polyethylene glycol 1000 succinate/sodium lauryl sulfate

Andrographolide (ADG) is a diterpenoid isolated from Andrographis paniculata with a wide spectrum of biological activities, including anti-inflammatory, anticancer and hepatoprotective effects. However, its poor water solubility and efflux by P-glycoprotein have resulted in lower bioavailability. In this study, ADG nanosuspensions (ADG-NS) were prepared using a wet media milling technique followed by freeze drying. d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS), a surfactant that inhibits P-glycoprotein function, and sodium lauryl sulfate were used as surface stabilizers. A Box-Behnken design was used to optimize the nanosuspension preparation. The products of these optimal preparation conditions were amorphous and possessed much faster dissolution in vitro than a coarse powder of ADG. The particle size and redispersibility index of the freeze-dried ADG-NS were 244.6±3.0 nm and 113%±1.14% (n=3), respectively. A short-term stability study indicated that the freeze-dried ADG-NS could remain highly stable as nanosuspensions during the testing period. A test of transport across a Caco-2 cell monolayer revealed that the membrane permeability (P_app) of ADG-NS was significantly higher than the permeability of the ADG coarse powder or ADG-NS without TPGS (P<0.01). Compared to the ADG coarse powder, a physical mixture, commercial dripping pills and ADG-NS without TPGS, ADG-NS exhibited significantly higher plasma exposure with significant enhancements in C_max and area under the curve of plasma concentration versus time from zero to the last sampling time (AUC_0-t ) (P<0.01). An evaluation of the anti-inflammatory effect on Carr-induced paw edema demonstrated that the ADG-NS were more effective in reducing the rate of paw swelling, producing a greater increase in the serum levels of nitric oxide (NO), Interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) (P<0.01) and an increase in superoxide dismutase activity (P<0.05) compared to the ADG coarse powder. This study indicated that nanosuspensions could act as an effective delivery device for ADG to enhance its oral bioavailability and biological efficacy.

κ-Carrageenan: An effective drug carrier to deliver curcumin in cancer cells and to induce apoptosis

The current study is to develop a natural drug carrier with seaweed derived polymers namely κ-Carrageenan (κ-Car) for drug delivery applications. κ-Car is a natural polysaccharide which derived from edible red seaweeds, they are easily available, non-toxic, cost effective, biodegradable and biocompatible nature. Curcumin (Cur) is a yellow-orange polyphenol existing in turmeric, which is predominantly used as spice and food coloring agent. The ultimate use of polymeric composites, especially those composed of natural polymers, has become a very interesting approach in recent drug delivery applications, due to their non-toxicity and biological origin. In this study the primary approach which depends on the loading of Curcumin into κ-Carrageenan was accomplished, and which (κ-Car-Cur) an active drug carrier was developed for drug delivery against selected lung cancer cells (A549). Thus, the κ-Car-Cur was synthesized by solvent evaporation method followed by freeze drying, and it was further characterized. From this study, it has been reported that the high encapsulation efficiency, good stability, and successful release of Cur from the carrier (κ-Car) was achieved. The drug release was more active at acidic pH 5.0 with the cumulative release of 78%, which is the favorable condition present in tumor microenvironments. The in vitro cellular applications studies of κ-Car-Cur demonstrated that, κ-Car-Cur composites induced higher cytotoxicity against selected cancer cells than free Cur and effectively involved to trigger cellular apoptosis in A549 cancer cells. Further, it was also possessed that inhibition of cell growth and changes in metabolic activity of cancer cells are the unique characteristic features of cellular apoptosis, through reactive oxygen species (ROS) generation. It also observed that there was a decrease in mitochondrial membrane potential (ΔψmΔψm) which leads to a cellular apoptosis during treatment with κ-Car-Cur. Hence, the study outcomes may provide the potential outline for the use of κ-Car-Cur as a promising tool to deliver drugs at intracellular level.

A recent trend of drug-nanoparticles in suspension for the application in drug delivery

Persistent development in nanomedicine has enabled successful nanosizing of most drug samples which, in turn, imparts remarkable properties to the drugs such as enhanced solubility and bioavailability for the applications in drug delivery. In this context, several review articles are available in scientific domain covering inorganic nanoparticles such as Au, Ag, SPIONs, Qdots, carbon nanotubes and graphene; however, this review covers the development of drug nanoparticles together with their possibilities and limitation from fabrication (bottom up vs top down) to application in drug delivery during the last 5 years. In addition, some distinguished studies and novel drug particles are presented in order to contribute significantly toward the understanding of drug nanocrystals and its use in drug delivery.

A novel gel based on an ionic complex from a dendronized polymer and ciprofloxacin: Evaluation of its use for controlled topical drug release

The development and characterization of a novel, gel-type material based on a dendronized polymer (DP) loaded with ciprofloxacin (CIP), and the evaluation of its possible use for controlled drug release, are presented in this work. DP showed biocompatible and non-toxic behaviors in cultured cells, both of which are considered optimal properties for the design of a final material for biomedical applications. These results were encouraging for the use of the polymer loaded with CIP (as a drug model), under gel form, in the development of a new controlled-release system to be evaluated for topical administration. First, DP-CIP ionic complexes were obtained by an acid-base reaction using the high density of carboxylic acid groups of the DP and the amine groups of the CIP. The complexes obtained in the solid state were broadly characterized using FTIR spectroscopy, XRP diffraction, DSC-TG analysis and optical microscopy techniques. Gels based on the DP-CIP complexes were easily prepared and presented excellent mechanical behaviors. In addition, optimal properties for application on mucosal membranes and skin were achieved due to their high biocompatibility and acute skin non-irritation. Slow and sustained release of CIP toward simulated physiological fluids was observed in the assays (in vitro), attributed to ion exchange phenomenon and to the drug reservoir effect. An in vitro bacterial growth inhibition assay showed significant CIP activity, corresponding to 38 and 58% of that exhibited by a CIP hydrochloride solution at similar CIP concentrations, against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. However, CIP delivery was appropriate, both in terms of magnitude and velocity to allow for a bactericidal effect. In conclusion, the final product showed promising behavior, which could be exploited for the treatment of topical and mucosal opportunistic infections in human or veterinary applications.

Nanoencapsulation of Red Ginseng Extracts Using Chitosan with Polyglutamic Acid or Fucoidan for Improving Antithrombotic Activities

The potential of nanoencapsulation using bioactive coating materials for improving antithrombotic activities of red ginseng extract (RG) was examined. RG-loaded chitosan (CS) nanoparticles were prepared using antithrombotic materials, polyglutamic acid (PGA) or fucoidan (Fu). Both CS-PGA (P-NPs, 360 ± 67 nm) and CS-Fu nanoparticles (F-NPs, 440 ± 44 nm) showed sustained ginsenoside release in an acidic environment and improved ginsenoside solubility by approximately 122.8%. Both in vitro rabbit and ex vivo rat platelet aggregation of RG (22.3 and 41.5%) were significantly (p < 0.05) decreased within P-NPs (14.4 and 30.0%) and F-NPs (12.3 and 30.3%), respectively. Although RG exhibited no effect on in vivo carrageenan-induced mouse tail thrombosis, P-NPs and F-NPs demonstrated significant effects, likely the anticoagulation activity of PGA and Fu. Moreover, in the in vivo rat arteriovenous shunt model, P-NPs (156 ± 6.8 mg) and F-NPs (160 ± 3.2 mg) groups showed significantly lower thrombus formation than that of RG (190 ± 5.5 mg). Therefore, nanoencapsulation using CS, PGA, and Fu is a potential for improving the antithrombotic activity of RG.

Nanomilling of Drugs for Bioavailability Enhancement: A Holistic Formulation-Process Perspective

Preparation of drug nanoparticles via wet media milling (nanomilling) is a very versatile drug delivery platform and is suitable for oral, injectable, inhalable, and buccal applications. Wet media milling followed by various drying processes has become a well-established and proven formulation approach especially for bioavailability enhancement of poorly water-soluble drugs. It has several advantages such as organic solvent-free processing, tunable and relatively high drug loading, and applicability to a multitude of poorly water-soluble drugs. Although the physical stability of the wet-milled suspensions (nanosuspensions) has attracted a lot of attention, fundamental understanding of the process has been lacking until recently. The objective of this review paper is to present fundamental insights from available published literature while summarizing the recent advances and highlighting the gap areas that have not received adequate attention. First, stabilization by conventionally used polymers/surfactants and novel stabilizers is reviewed. Then, a fundamental understanding of the process parameters, with a focus on wet stirred media milling, is revealed based on microhydrodynamic models. This review is expected to bring a holistic formulation-process perspective to the nanomilling process and pave the way for robust process development scale-up. Finally, challenges are indicated with a view to shedding light on future opportunities.

Recent advances in the engineering of nanosized active pharmaceutical ingredients: Promises and challenges

The advances in the field of nanotechnology have revolutionized the field of delivery of poorly soluble active pharmaceutical ingredients (APIs). Nanosized formulations have been extensively investigated to achieve a rapid dissolution and therefore pharmacokinetic properties similar to those observed in solutions. The present review outlines the recent advances, promises and challenges of the engineering nanosized APIs. The principles, merits, demerits and applications of the current 'bottom-up' and 'top-down' technologies by which the state of the art nanosized APIs can be produced were described. Although the number of research reports on the nanoparticle engineering topic has been growing in the last decade, the challenge is to take numerous research outcomes and convert them into strategies for the development of marketable products.

A Review: Pharmaceutical and Pharmacokinetic Aspect of Nanocrystalline Suspensions

Nanocrystals have emerged as a potential formulation strategy to eliminate the bioavailability-related problems by enhancing the initial dissolution rate and moderately super-saturating the thermodynamic solubility. This review contains an in-depth knowledge of, the processing method for formulation, an accurate quantitative assessment of the solubility and dissolution rates and their correlation to observe pharmacokinetic data. Poor aqueous solubility is considered the major hurdle in the development of pharmaceutical compounds. Because of a lack of understanding with regard to the change in the thermodynamic and kinetic properties (i.e., solubility and dissolution rate) upon nanosizing, we critically reviewed the literatures for solubility determination to understand the significance and accuracy of the implemented analytical method. In the latter part, we reviewed reports that have quantitatively studied the effect of the particle size and the surface area change on the initial dissolution rate enhancement using alternative approaches besides the sink condition dissolution. The lack of an apparent relationship between the dissolution rate enhancement and the observed bioavailability are discussed by reviewing the reported in vivo data on animal models along with the particle size and food effect. The review will provide comprehensive information to the pharmaceutical scientist in the area of nanoparticulate drug delivery.

Enhanced oral bioavailability of fenofibrate using polymeric nanoparticulated systems: physicochemical characterization and in vivo investigation

Background

The intention of this research was to prepare and compare various solubility-enhancing nanoparticulated systems in order to select a nanoparticulated formulation with the most improved oral bioavailability of poorly water-soluble fenofibrate.

Methods

The most appropriate excipients for different nanoparticulated preparations were selected by determining the drug solubility in 1% (w/v) aqueous solutions of each carrier. The polyvinylpyrrolidone (PVP) nanospheres, hydroxypropyl-β-cyclodextrin (HP-β-CD) nanocorpuscles, and gelatin nanocapsules were formulated as fenofibrate/PVP/sodium lauryl sulfate (SLS), fenofibrate/HP-β-CD, and fenofibrate/gelatin at the optimized weight ratios of 2.5:4.5:1, 1:4, and 1:8, respectively. The three solid-state products were achieved using the solvent-evaporation method through the spray-drying technique. The physicochemical characterization of these nanoparticles was accomplished by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Their physicochemical properties, aqueous solubility, dissolution rate, and pharmacokinetics in rats were investigated in comparison with the drug powder.

Results

Among the tested carriers, PVP, HP-β-CD, gelatin, and SLS showed better solubility and were selected as the most appropriate constituents for various nanoparticulated systems. All of the formulations significantly improved the aqueous solubility, dissolution rate, and oral bioavailability of fenofibrate compared to the drug powder. The drug was present in the amorphous form in HP-β-CD nanocorpuscles; however, in other formulations, it existed in the crystalline state with a reduced intensity. The aqueous solubility and dissolution rates of the nanoparticles (after 30 minutes) were not significantly different from one another. Among the nanoparticulated systems tested in this study, the initial dissolution rates (up to 10 minutes) were higher with the PVP nanospheres and HP-β-CD nanocorpuscles; however, neither of them resulted in the highest oral bioavailability. Irrespective of relatively retarded dissolution rate, gelatin nanocapsules showed the highest apparent aqueous solubility and furnished the most improved oral bioavailability of the drug (~5.5-fold), owing to better wetting and diminution in crystallinity.

Conclusion

Fenofibrate-loaded gelatin nanocapsules prepared using the solvent-evaporation method through the spray-drying technique could be a potential oral pharmaceutical product for administering the poorly water-soluble fenofibrate with an enhanced bioavailability.

Review for carrageenan-based pharmaceutical biomaterials: favourable physical features versus adverse biological effects

Carrageenan (CRG) is a family of natural polysaccharides derived from seaweeds and has widely been used as food additives. In the past decade, owing to its attractive physicochemical properties, CRG has been developed into versatile biomaterials vehicles for drug delivery. Nevertheless, studies also emerged to reveal its adverse effects on the biological system. In this review, we critically appraise the latest literature (two thirds since 2008) on the development of CRG-based pharmaceutical vehicles and the perspective of using CRG for broader biomedical applications. We focus on how current strategies exploit the unique gelling mechanisms, strong water absorption and abundant functional groups of the three major CRG varieties. Notably, CRG-based matrices are demonstrated to increase drug loading and drug solubility, enabling release of orally administrated drugs in zero-order or in a significantly prolonged period. Other amazing features, such as pH-sensitivity and adhesive property, of CRG-based formulations are also introduced. Finally, we discuss the adverse influence of CRG on the human body and then suggest some future directions for the development of CRG-based biomaterials for broader applications in biomedicine.

A brief literature and patent review of nanosuspensions to a final drug product

Particle size reduction can be used for enhancing the dissolution of poorly water-soluble drugs in order to enhance bioavailability. In nanosuspensions, the particle size of the drug is reduced to nanometer size. Nanosuspensions after downstream processing into drug products have successfully shown its impact on formulation design, the augmentation of product life cycle, patent life, and therapeutic efficacy. Formulation considerations for the nanosuspension formulation, its processing into a solid form, and aspects of material characterization are discussed. Technology assessments and feasibility of upstream processes for nanoparticle creation, and subsequently transformation into a drug product via the downstream processes have been reviewed. This paper aims to bridge formulation and process considerations along with patent reviews and may provide further insight into understanding the science and the white space. An analysis of current patent outlook and future trends is described to fully understand the limitations and opportunities in intellectual property generation.

Enhanced bioavailability of apigenin via preparation of a carbon nanopowder solid dispersion

In this study, a novel carbon nanopowder (CNP) drug carrier was developed to improve the oral bioavailability of apigenin (AP). Solid dispersions (SDs) of AP with CNP were prepared, and their in vitro drug release and in vivo performance were evaluated. The physicochemical properties of the formulations were examined by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. Drug release profiles showed that AP dissolution from the CNP-AP system (weight ratio, 6:1) after 60 minutes improved by 275% compared with that of pure AP. Moreover, the pharmacokinetic analysis of SD formulations in rats showed that the AP area under the curve_0–t value was 1.83 times higher for the CNP-AP system than for pure AP, indicating that its bioavailability was significantly improved. In addition, compared with pure AP, SDs had a significantly higher peak and shorter time to peak. Preliminary intestinal toxicity tests indicated that there was no significant difference in the tissues of the rats treated with the CNP-AP system, rats treated with the CNP alone, and controls. In conclusion, CNP-based SDs could be used for enhancing the bioavailability of poorly water-soluble drugs while also improving drug safety.

Enhanced bioavailability of poorly absorbed hydrophilic compounds through drug complex/in situ gelling formulation

BCS class III hydrophilic compounds are often associated with low oral bioavailability due to their poor epithelial permeability in the gastrointestinal tract. In this study, we reported an approach of incorporating a drug complex into an in situ gelling muco-adhesive carrier to achieve an improved bioavailability of a poorly absorbed hydrophilic compound. A new molecular entity (RWJ-445167) from Johnson and Johnson was used as a model compound. The compound was first complexed with sodium lauryl sulfate (SLS). The complex was then incorporated into an in situ gelling muco-adhesive carrier Cremophor for formulation characterization and rat pharmacokinetic (PK) studies. The study results showed that RWJ-445167 bound to SLS at a stoichiometric ratio. By complexing with SLS, the compound became lipophilic. The aqueous solubility of RWJ-445167 dropped to 0.58 mg/mL for the complex from 61 mg/mL for the free compound, while the partitioning coefficient of the complex increased to 7.59, compared with 0.05 of the free compound. In the rat PK study, with duodenal administration, the complex in the in situ-gelling formulation achieved 28.24% of bioavailability, compared to 4.26% of the free compound solution. The enhanced bioavailability was also significantly higher than those in the RWJ-445167/SLS physical mixture in Cremophor (14.91%), the complex in non-gelling carrier PEG 400 (9.95%) and the RWJ-445167/SLS physical mixture in PEG 400 carrier (8.60%). The study demonstrates that incorporation of a drug complex into an in situ gelling formulation provides a new approach to improving bioavailability of BCS class III drugs.

Enhanced solubility and intestinal absorption of candesartan cilexetil solid dispersions using everted rat intestinal sacs

OBJECTIVE

Candesartan cilexetil (CAN) is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These key factors are responsible for its incomplete intestinal absorption.

METHODS

In this study, we investigated to enhance the absorption of CAN by improving its solubility and inhibiting intestinal P-gp activity. A phase solubility method was used to evaluate the aqueous solubility of CAN in PVP K30 (0.2-2%). Gibbs free energy [Formula: see text] values were all negative. Solubility was enhanced by the freeze drying technique. The in vitro dissolution was evaluated using the USP paddle method. The interaction between drug and carrier was evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) studies. Naringin was selected as P-gp inhibitor. Absorption studies were performed using the everted gut sac model from rat jejunum. The drug analysis was performed by HPLC.

RESULTS

FTIR spectra revealed no interaction between drug and PVP K30. From XRD and DSC data, CAN was in the amorphous form, which explains the cumulative release of drug from its prepared systems. We noticed an enhancement of CAN absorption by improving its solubility and inhibiting the P-gp activity. The significant results (p < 0.05) were obtained for freeze dried solid dispersions in the presence of P-gp inhibitor than without naringin (15 mg/kg) with an absorption enhancement of 8-fold.

CONCLUSION

Naringin, a natural flavonoid, has no undesirable side effects. Therefore, it could be employed as an excipient in the form of solid dispersions to increase CAN intestinal absorption and its oral bioavailability.

Preparation and evaluation of raloxifene-loaded solid dispersion nanoparticle by spray-drying technique without an organic solvent

The aim of this study was to improve the physicochemical properties and bioavailability of a poorly water-soluble drug, raloxifene by solid dispersion (SD) nanoparticles using the spray-drying technique. These spray-dried SD nanoparticles were prepared with raloxifene (RXF), polyvinylpyrrolidone (PVP) and Tween 20 in water. Reconstitution of optimized RXF-loaded SD nanoparticles in pH 1.2 medium showed a mean particle size of approximately 180 nm. X-ray diffraction and differential scanning calorimetry indicated that RXF existed in an amorphous form within spray-dried nanoparticles. The optimized formulation showed an enhanced dissolution rate of RXF at pH 1.2, 4.0, 6.8 and distilled water as compared to pure RXF powder. The improved dissolution of raloxifene from spray-dried SD nanoparticles appeared to be well correlated with enhanced oral bioavailability of raloxifene in rats. Furthermore, the pharmacokinetic parameters of the spray-dried SD nanoparticles showed increased AUC(0-∞) and C(max) of RXF by approximately 3.3-fold and 2.3-fold, respectively. These results suggest that the preparation of RXF-SD nanoparticles using the spray drying technique without organic solvents might be a promising approach for improving the oral bioavailability of RXF.

Drug nanocrystals in the commercial pharmaceutical development process

Nanosizing is one of the most important drug delivery platform approaches for the commercial development of poorly soluble drug molecules. The research efforts of many industrial and academic groups have resulted in various particle size reduction techniques. From an industrial point of view, the two most advanced top-down processes used at the commercial scale are wet ball milling and high pressure homogenization. Initial issues such as abrasion, long milling times and other downstream-processing challenges have been solved. With the better understanding of the biopharmaceutical aspects of poorly water-soluble drugs, the in vivo success rate for drug nanocrystals has become more apparent. The clinical effectiveness of nanocrystals is proven by the fact that there are currently six FDA approved nanocrystal products on the market. Alternative approaches such as bottom-up processes or combination technologies have also gained considerable interest. Due to the versatility of nanosizing technology at the milligram scale up to production scale, nanosuspensions are currently used at all stages of commercial drug development, Today, all major pharmaceutical companies have realized the potential of drug nanocrystals and included this universal formulation approach into their decision trees.

Proteomic analysis of embryo development in rice (Oryza sativa)

Although embryo development is a major subject in plant growth and development research, a number of aspects of the mechanism of this development process remain unknown. Rice (Oryza sativa) is an excellent monocot plant model for studying embryogenesis with a known genome sequence. Here, we conducted proteomic analysis of embryo development in rice (O. sativa L. ssp. indica cv. 9311). The aim was to investigate and characterize the changes in the protein expression profile during embryo development. For this purpose, the proteome of developing embryos was characterized by two-dimensional gel electrophoresis and nano liquid chromatography/mass spectrometry/mass spectrometry. Proteomic analyses identified 275 differentially expressed proteins throughout the 5 sequential developmental stages from 5 to 30 days after pollination. Most of these proteins were classified into eight functional categories: metabolism, protein synthesis/destination, disease and defense, transporter, transcription, signal transduction, cell growth/division, and storage proteins, which were involved in different cellular and metabolic processes. Hierarchical clustering analyses of protein expression profiles showed that highly expressed proteins in early stages were involved in metabolism, protein synthesis/destination, and most of the other cellular functions, whereas the proteins highly expressed in later stages functioned in the desiccation and dormancy of the embryo.