Nanocrystals as tool to improve piroxicam dissolution rate in novel orally disintegrating tablets

Tabletized Nanomedicine: From the Current Scenario to Developing Future Medicine

The limitations of conventional therapeutic treatments prevailed in the development of nanotechnology-based medical formulations, termed nanomedicine. Nanomedicine is an advanced medicine that often consists of therapeutic agent(s) embedded in biodegradable or biocompatible nanomaterial-based formulations. Among nanomedicine approaches, tablet (oral) nanomedicine is still under development. In tabletized nanomedicine, the dynamic interplay between nanoformulations and the intricate milieu of the gastrointestinal tract simulates a pivotal role, particularly accentuating the influence exerted upon the luminal, mucosal, and epithelial cells. In this work, we document the perspectives and opportunities of nanoformulations toward the development of tabletized nanomedicine. This review also unveils the notion of integrating nanomedicine within a tablet formulation, which facilitates the controlled release of drugs, biomolecules, and agent(s) from the formulation to achieve a better therapeutic response. Finally, an attempt was made to explore current trends in nanomedicine technology such as bacteriophage, probiotic, and oligonucleotide tabletized nanomedicine and the combination of nanomedicine with imaging agents, i.e., nanotheranostics.

Preparation and Investigation of a Nanosized Piroxicam Containing Orodispersible Lyophilizate

Non-steroidal anti-inflammatory piroxicam (PRX) is a poorly water-soluble drug that provides relief in different arthritides. Reducing the particle size of PRX increases its bioavailability. For pediatric, geriatric, and dysphagic patients, oral dispersible systems ease administration. Moreover, fast disintegration followed by drug release and absorption through the oral mucosa can induce rapid systemic effects. We aimed to produce an orodispersible lyophilizate (OL) consisting of nanosized PRX. PRX was solved in ethyl acetate and then sonicated into a poloxamer-188 solution to perform spray-ultrasound-assisted solvent diffusion-based nanoprecipitation. The solid form was formulated via freeze drying in blister sockets. Mannitol and sodium alginate were applied as excipients. Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were used to determine the particle size. The morphology was characterized by scanning electron microscopy (SEM). To establish the crystallinity, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used. A disintegration and in vitro dissolution test were performed. DLS and NTA presented a nanosized PRX diameter. The SEM pictures showed a porous structure. PRX became amorphous according to the XRPD and DSC curves. The disintegration time was less than 1 min and the dissolution profile improved. The final product was an innovative anti-inflammatory drug delivery system.

Preparation of Piroxicam nanosuspensions by high pressure homogenization and evaluation of improved bioavailability

OBJECTIVE

Inflammation is a natural response of the organism, involving events responsible for releasing chemical mediators and requiring treatments of symptoms such as pain, redness, heat, swelling, and loss of tissue function. Piroxicam (PRX) is a non-steroidal anti-inflammatory drug with the effect of nonselective COX inhibitor activity; however, it shows poor bioavailability caused by the poor and slow water solubility. In this study, we developed PRX nanosuspensions with 200-500 nm in diameter to increase the bioavailability of PRX by improving its solubility.

METHODS

PRX nanosuspensions were fabricated by High pressure homogenization method with PVA, SDS and Tween 80. The nanosuspensions were characterized by XRD, FTIR, DSC, and in vitro release. In vivo pharmacokinetic properties and anti-inflammatory effects were also investigated in rabbits.

RESULTS

PRX nanosuspensions significantly increased the solubility (14.89 ± 0.03 mg/L for pure PRX and 16.75 ± 0.05 mg/L for PRX nanosuspensions) and dissolution rate as compared to the pure PRX (p < 0.05). Orally administered PRX nanosuspension (AUC 0-t is 49.26 ± 4.29 μg/mL × h) significantly improved the bioavailability of PRX (AUC 0-t is 28.40 ± 12.11 μg/mL × h). The anti-inflammatory effect of PRX nanosuspension was also investigated in rabbits and it was observed that PRX nanosuspension treatment significantly improved the inhibition of COX-2 and NFκB expression as compared to the PRX treatment (p < 0.05).

CONCLUSIONS

The results in this study indicate that PRX nanosuspension is a promising nanomedicine for enhancing the anti-inflammatory activity of PRX and has a high potential for the treatment of inflammation.

Orally Dispersible Dosage Forms for Paediatric Use: Current Knowledge and Development of Nanostructure-Based Formulations

The paediatric population has always suffered from a lack of medicines tailored to their needs, especially in terms of accurate dosage, stability and acceptability. Orodispersible dosage forms have gone through a resurrection as an alternative to liquid formulations or fractioned solid formulations, although they are still subject to several inconveniences, among which the unpleasant taste and the low oral bioavailability of the API are the most significant hurdles in the way of achieving an optimal drug product. Nanostructures can address these inconveniences through their size and variety, owing to the plethora of materials that can be used in their manufacturing. Through the formation and functionalisation of nanostructures, followed by their inclusion in orodispersible dosage forms, safe, stable and acceptable medicines intended for paediatric use can be developed.

Integration of lornoxicam nanocrystals into hydroxypropyl methylcellulose-based sustained release matrix to form a novel biphasic release system

The study aims to (a) enhance the solubility of a poorly soluble drug by optimization of nanocrystal formulation using the top-down approach and (b) modify the release profile of this drug, which exhibits a short elimination half-life, by the integration of a fast-release phase containing the optimized nanocrystals and a sustained-release phase in a compression-coated tablet. Nanocrystals of the model drug (lornoxicam; LNX) was prepared by simultaneous application of jet-milling and ball-milling techniques. Investigation of the precipitation inhibition capacity, thermal property, and interaction of different polymers with the drug revealed polyvinyl pyrrolidone K30 (PVP) as the most effective stabilizer for nanocrystals. The immediate-release layer containing the optimized nanocrystals (size of 279.5 ± 11.25 nm and polydispersity index of 0.204 ± 0.01) was then compressed on a zero-order sustained-release matrix core using different derivatives of hydroxypropyl methylcellulose (HPMC). Application of the Design of Experiment approach (DoE) was applied to optimize the formulation of tablet. Analysis of drug concentration in dog plasma by liquid chromatography-tandem mass spectrometry demonstrated an improvement in the release behavior of LNX from the optimal compression-coated tablet integrating a HPMC-based sustained release matrix core and a PVP-stabilized lornoxicam nanocrystals coating layer compared to the reference product.

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.

Oral Formulation Based on Irbesartan Nanocrystals Improve Drug Solubility, Absorbability, and Efficacy

We previously reported that the bioavailability (BA) of irbesartan (IRB), a BSC class II drug, was improved by preparing nanocrystalline suspensions. However, nanocrystalline suspensions have chemical and physical instabilities and must be converted into tablets through drying approaches in order to overcome such instabilities. In this study, we attempted to design a molded tablet based on nanocrystalline IRB suspensions (IRB-NP tablet) and investigated the effects of this IRB-NP tablet on blood pressure (BP) in a stroke-prone spontaneously hypertensive (SHR-SP) rat. The IRB-NP tablet (with a hardness of 42.6 N) was developed by combining various additives (methylcellulose, 2-hydroxypropyl-β-cyclodextrin HPβCD, D-mannitol, polyvinylpyrrolidone, and gum arabic) followed by bead-milling and freeze-drying treatments. The mean particle size in the redispersions of the IRB-NP tablet was approximately 118 nm. The solubility and intestinal absorption of IRB in the IRB-NP tablet were significantly enhanced in comparison with the microcrystalline IRB tablet (IRB-MP tablet), and both solubility and clathrin-dependent endocytosis helped improve the low BA of the IRB. In addition, the BP-reducing effect of the IRB-NP tablet was significantly higher than that of the IRB-MP tablet. These results provide useful information for the preservation of nanocrystalline suspensions of BCS class II drugs, such as IRB.

Production and isolation of pharmaceutical drug nanoparticles

Nanosizing of pharmaceutical drug particles is one of the most important drug delivery platforms approaches for the commercial development of poorly water-soluble drug molecules. Though nanosizing of drug particles has been proven to greatly enhance drugs dissolution rate and apparent solubility, nanosized materials have presented significant challenges for their formulation as solid dosage forms (e.g. tablets, capsules). This is due to the strong Van der Waals attraction forces between dry nanoparticles leading to aggregation, cohesion, and consequently poor flowability. In this review, the broad area of nanomedicines is overviewed with the primary focus on drug nanocrystals and the top-down and bottom-up methods used in their fabrication. The review also looks at how nanosuspensions of pharmaceutical drugs are generated and stabilised, followed by subsequent strategies for isolation of the nanoparticles. A perspective on the future outlook for drug nanocrystals is also presented.

Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation

Piroxicam (PRX) is a commonly prescribed nonsteroidal anti-inflammatory drug. Its efficacy, however, is partially limited by its low water solubility. In recent years, different studies have tackled this problem and have suggested delivering PRX through solid dispersions. All these strategies, however, involve the use of potentially harmful solvents for the loading procedure. Since piroxicam is soluble in supercritical CO₂ (scCO₂), the present study aims, for the first time, to adsorb PRX onto mesoporous silica using scCO₂, which is known to be a safer and greener technique compared to the organic solvent-based ones. For comparison, PRX is also loaded by adsorption from solution and incipient wetness impregnation using ethanol as solvent. Two different commercial mesoporous silicas are used (SBA-15 and Grace Syloid^® XDP), which differ in porosity order and surface silanol population. Physico-chemical analyses show that the most promising results are obtained through scCO₂, which yields the amorphization of PRX, whereas some crystallization occurs in the case of adsorption from solution and IWI. The highest loading of PRX by scCO₂ is obtained in SBA-15 (15 wt.%), where molecule distribution appears homogeneous, with very limited pore blocking.

Strategies and formulations of freeze-dried tablets for controlled drug delivery

The freeze-drying process has been particularly attractive for preparing tablets for controlled drug release. Although traditional methods, such as granulation or direct compression methods, have been used in various studies to produce tablets with controlled release, freeze-drying processes have been utilized in certain circumstances due to their distinct advantages. However, overall, further development of these strategies, which started with early studies on orally disintegrating tablets, is still necessary. In this review, the incorporation of different formulations into freeze-dried tablets will be discussed. Moreover, the use of excipients, freeze-drying conditions, formulation reconstitution and tablet structure for optimizing the performance of freeze-dried tablets will be reported, including strategies with nanoformulations and natural materials. Generally, this discussion with potential approaches will benefit further development of freeze-dried tablets containing drugs in the pharmaceutical industry.

The potential of intranasal delivery of nanocrystals in powder form on the improvement of zaleplon performance: in-vitro, in-vivo assessment

OBJECTIVE

The present work focuses on improving zaleplon (ZAP) performance through nanosizing its insoluble particles which were then delivered intranasally in powder form.

SIGNIFICANCE

Since nanopowders have an exceptional ability to cross cell membrane, their absorption is facilitated in the solid form. Hence, delivering insoluble ZAP nanocrystals (NC) through intranasal route improves its bioavailability due to both nanosization and the escape of hepatic metabolism.

METHODS

Nanocrystals were prepared by anti-solvent precipitation followed by probe sonication in presence of Soluplus^®, Poloxamer-188 (0.25%), sodium lauryl sulfate (0.5%), and mannitol. Physicochemical evaluation of the prepared NC was done by DSC and XRPD. TGA was performed for stability detection. Ex vivo permeation study through isolated cattle nasal mucosal membrane, in addition to an in vivo bioavailability study was performed for assessment of the prepared NC.

RESULTS

Nanosization to 200 nm contributed to the enhancement in dissolution ∼100% within 30 min and reduced half-life to 1.63 min. Confirmation of adsorption of polymers over NC' surface was elucidated. TGA confirmed their thermal stability. Ex vivo permeation study showed a 2.7 enhancement ratio in favor of the prepared NC. Both the extent and rate of NC absorption through nasal mucosa of rabbits were significantly higher (p ˂ .05) than in case of oral tablets. The relative bioavailability of NC was increased 3.14 times as compared to the Sleep aid^® tablets.

CONCLUSION

The intranasal delivery of nanoscale ZAP powder proved to be a successful alternative to oral formulations that suffer poor absorption and limited bioavailability.

Development and optimisation of simulated salivary fluid for biorelevant oral cavity dissolution

Drug release within the oral cavity can be of paramount importance for formulations that are designed for specific purposes such as taste-masking, faster onset of therapeutic action, localization of treatment or avoidance of first-pass metabolism. Preclinical methods for assessment of dissolution in the oral cavity are necessary for design and development of these formulation but currently there is no consensus on what variables should be defined to achieve biorelevance in these tests. In this study, biorelevant simulated salivary fluids (SSFs) that can be uniformly applied for oral cavity dissolution testing were developed. Unstimulated saliva (US) SSF and stimulated saliva (SS) SSF were separately developed since the two states significantly differ. Physicochemical properties including pH, buffer capacity, surface tension and viscosity were assessed during development and optimised to mimic human saliva (HS). In order to account for the salivary proteins in HS, use of bovine submaxillary mucin (BSM) and porcine gastric mucin (PGM) in SSFs was evaluated. Following optimisation of the SSFs, biorelevance of the developed SSFs to HS was assessed by their comparative physicochemical properties as well as dissolution profiles of three diverse model compounds (sildenafil citrate, efavirenz, and caffeine) which showed comparable profiles between the SSFs and HS. This work addresses the lack of uniformed biorelevant dissolution media for oral cavity dissolution studies and provides a basis for standardised dissolution tests that provide consistency and harmonisation in future oral cavity dissolution studies. We envisage that this will have a positive impact on the development of new medicines that require functionality in the oral cavity.

Degrees of order: A comparison of nanocrystal and amorphous solids for poorly soluble drugs

Poor aqueous solubility is currently a prevalent issue in the development of small molecule pharmaceuticals. Several methods are possible for improving the solubility, dissolution rate and bioavailability of Biopharmaceutics Classification System (BCS) class II and class IV drugs. Two solid state approaches, which rely on reductions in order, and can theoretically be applied to all molecules without any specific chemical prerequisites (compared with e.g. ionizable or co-former groups, or sufficient lipophilicity), are the use of the amorphous form and nanocrystals. Research involving these two approaches is relatively extensive and commercial products are now available based on these technologies. Nevertheless, their formulation remains more challenging than with conventional dosage forms. This article describes these two technologies from both theoretical and practical perspectives by briefly discussing the physicochemical backgrounds behind these approaches, as well as the resulting practical implications, both positive and negative. Case studies demonstrating the benefits and challenges of these two techniques are presented.

Emerging role of nanosuspensions in drug delivery systems

Rapid advancement in drug discovery process is leading to a number of potential new drug candidates having excellent drug efficacy but limited aqueous solubility. By virtue of the submicron particle size and distinct physicochemical properties, nanosuspension has the potential ability to tackle many formulation and drug delivery issues typically associated with poorly water and lipid soluble drugs. Conventional size reduction equipment such as media mill and high-pressure homogenizers and formulation approaches such as precipitation, emulsion-solvent evaporation, solvent diffusion and microemulsion techniques can be successfully implemented to prepare and scale-up nanosuspensions. Maintaining the stability in solution as well as in solid state, resuspendability without aggregation are the key factors to be considered for the successful production and scale-up of nanosuspensions. Due to the considerable enhancement of bioavailability, adaptability for surface modification and mucoadhesion for drug targeting have significantly expanded the scope of this novel formulation strategy. The application of nanosuspensions in different drug delivery systems such as oral, ocular, brain, topical, buccal, nasal and transdermal routes are currently undergoing extensive research. Oral drug delivery of nanosuspension with receptor mediated endocytosis has the promising ability to resolve most permeability limited absorption and hepatic first-pass metabolism related issues adversely affecting bioavailability. Advancement of enabling technologies such as nanosuspension can solve many formulation challenges currently faced among protein and peptide-based pharmaceuticals.

Nanocrystals: A perspective on translational research and clinical studies

Poorly soluble small molecules typically pose translational hurdles owing to their low solubility, low bioavailability, and formulation challenges. Nanocrystallization is a versatile method for salvaging poorly soluble drugs with the added benefit of a carrier-free delivery system. In this review, we provide a comprehensive analysis of nanocrystals with emphasis on their clinical translation. Additionally, the review sheds light on clinically approved nanocrystal drug products as well as those in development.

Nanocrystals of Poorly Soluble Drugs: Drug Bioavailability and Physicochemical Stability

Many approaches have been developed over time to overcome the bioavailability limitations of poorly soluble drugs. With the advances in nanotechnology in recent decades, science and industry have been approaching this issue through the formulation of drugs as nanocrystals, which consist of “pure drugs and a minimum of surface active agents required for stabilization”. They are defined as “carrier-free submicron colloidal drug delivery systems with a mean particle size in the nanometer range, typically between 10–800 nm”. The primary importance of these nanoparticles was the reduction of particle size to nanoscale dimensions, with an increase in the particle surface area in contact with the dissolution medium, and thus in bioavailability. This approach has been proven successful, as demonstrated by the number of such drug products on the market. Nonetheless, despite the definition that indicates nanocrystals as a “carrier-free” system, surface active agents are necessary to prevent colloidal particles aggregation and thus improve stability. In addition, in more recent years, nanocrystal properties and technologies have attracted the interest of researchers as a means to obtain colloidal particles with modified biological properties, and thus their interest is now also addressed to modify the drug delivery and targeting. The present work provides an overview of the achievements in improving the bioavailability of poorly soluble drugs according to their administration route, describes the methods developed to overcome physicochemical and stability-related problems, and in particular reviews different stabilizers and surface agents that are able to modify the drug delivery and targeting.

Development of a tin oxide carrier with mesoporous structure for improving the dissolution rate and oral relative bioavailability of fenofibrate

Background

Biopharmaceutics classification system class II drugs have low solubility, which limits their extent and speed of absorption after oral administration. Over the years, mesoporous materials have been widely used to increase the dissolution rate and oral relative bioavailability of poorly water-soluble drugs.

Objectives

In order to improve the dissolution rate and increase oral relative bioavailability of the poorly water-soluble drugs, a tin oxide carrier (MSn) with a mesoporous structure was successfully synthesized.

Methods

In this study, MSn was synthesized using mesoporous silica material (SBA-15) as the template. Fenofibrate (FNB) was adsorbed into the channels of MSn by an adsorption method. Characterizations of the pure FNB, MSn, physical mixture of the drug and MSn (PM; 1:1) and FNB-loaded MSn (FNB-MSn) samples were carried out by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption/desorption, powder X-ray diffractometer (PXRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. Cytotoxicity assay (MTT) was used to evaluate the cytotoxicity of MSn. In vitro dissolution studies were performed to investigate the dissolution rate of FNB-MSn. In vivo pharmacokinetic studies were used to investigate the changes of plasma drug concentrations of FNB-MSn tablets and commercial FNB tablets in rabbits.

Results

Detailed characterization showed that FNB in the channels of MSn was present in an amorphous state. The in vitro release tests demonstrated that MSn with a good biocompatibility could effectively enhance the dissolution rate of FNB. Pharmacokinetic results indicated that MSn significantly increased the oral relative bioavailability of FNB.

Conclusion

MSn can be regarded as a promising carrier for an oral drug delivery system.

The pharmaceutical applications of a biopolymer isolated from Trigonella foenum-graecum seeds: Focus on the freeze-dried matrix forming capacity

The aim of the present study was to evaluate the funtion of fenugreek seed mucilage (FSM) as potential matrix forming agent for orodispersible pharmaceutical lyophilisates. The FSM was isolated and characterized. FSM colloidal dispersions were prepared and the rheological evaluation was performed. Oral lyophilisates (OLs) with different FSM concentrations, containing meloxicam as model drug were prepared by freeze drying method. The OLs were characterized and compared to gelatin containing tablets, prepared under the same conditions. The FSM dispersions revealed shear thinning flow type. Based on colloidal dispersions' rheological properties, five FSM concentrations were taken forward to the lyophilization step. Completely dry and elegant tablets were obtained. Texture analysis indicated highly porous structures, confirmed by SEM analysis, which explain the fast disintegration properties. All the prepared tablets disintegrated in less than 47 s. The disintegration process was prolonged by the increase in FSM content, due to the high viscosity the polymer creates in aqueous media. FSM tablets presented longer disintegration times, as compared to gelatin tablets, but also higher crushing strength. Considering the fast disintegration and the high crushing strength, FSM is a good candidate as matrix forming agent for fast disintegrating dosage forms or other freeze-dried preparations.

Enhanced Solubility and Dissolution Rate of Lacidipine Nanosuspension: Formulation Via Antisolvent Sonoprecipitation Technique and Optimization Using Box-Behnken Design

Lacidipine (LCDP) is a highly lipophilic calcium channel blocker of poor aqueous solubility leading to poor oral absorption. This study aims to prepare and optimize LCDP nanosuspensions using antisolvent sonoprecipitation technique to enhance the solubility and dissolution of LCDP. A three-factor, three-level Box-Behnken design was employed to optimize the formulation variables to obtain LCDP nanosuspension of small and uniform particle size. Formulation variables were as follows: stabilizer to drug ratio (A), sodium deoxycholate percentage (B), and sonication time (C). LCDP nanosuspensions were assessed for particle size, zeta potential, and polydispersity index. The formula with the highest desirability (0.969) was chosen as the optimized formula. The values of the formulation variables (A, B, and C) in the optimized nanosuspension were 1.5, 100%, and 8 min, respectively. Optimal LCDP nanosuspension had particle size (PS) of 273.21 nm, zeta potential (ZP) of -32.68 mV and polydispersity index (PDI) of 0.098. LCDP nanosuspension was characterized using x-ray powder diffraction, differential scanning calorimetry, and transmission electron microscopy. LCDP nanosuspension showed saturation solubility 70 times that of raw LCDP in addition to significantly enhanced dissolution rate due to particle size reduction and decreased crystallinity. These results suggest that the optimized LCDP nanosuspension could be promising to improve oral absorption of LCDP.

Development of oral lyophilisates containing meloxicam nanocrystals using QbD approach

The aim of this study was to develop oral lyophilisates with improved meloxicam (MEL) dissolution, optimizing each step of the preparation by design of experiments. First, meloxicam nanosuspensions were prepared by high-pressure homogenization (HPH), using PVP, Poloxamer or PEG as stabilizers and were subjected to freeze-drying using mannitol as cryoprotectant. The effects of the stabilizers and cryoprotectant were assessed and an optimal formulation was generated within the Design Space where the particle sizes and the PDIs are at their lowest values. The optimal formulation was used at the preparation of oral lyophilisates. Sodium alginate (SA) and croscarmellose sodium (CCS) were tested as matrix forming agents and three different freezing regimes were applied. The formulation was optimized, choosing the polymer that yielded both high mechanical strength and fast MEL dissolution. Poloxamer led to particle size reduction down to 10.27% of the initial size, meaning 477.6±7.5nm, with a slight increase during freeze-drying process. PEG showed lower nanonizing capacity during HPH, but freeze-drying produced further diminution of the particle size. Since Poloxamer provided advanced size reduction while preserving MEL crystallinity, it was used for the optimized formulation containing 1% Poloxamer and 5% mannitol added before freeze-drying. SA showed good structural properties when compared to CCS and allowed fast MEL dissolution at low ratios. The optimal formulation contained 1.157% of SA was subjected to thermal treatment during freeze-drying. It disintegrated in 3.33s and released 77.14% of the MEL after 2min. The quality by design (QbD) approach for the development of pharmaceutical products ensured high quality of the dosage form and good understanding of the preparation process.

Design and in vitro characterization of ivermectin nanocrystals liquid formulation based on a top-down approach

The aim of this study was to develop ivermectin (IVM) nanosuspensions (NSs) to improve the dissolution rate of this poorly water-soluble drug. Different NSs combining different stabilizers, i.e. poloxamer 188 (P188), polysorbate 80 (T80), polyvinylpyrrolidone (PVP), and sodium lauryl sulfate (SLS), were prepared by high-pressure homogenization. The stabilizers were selected based on the saturation solubility and IVM stability within 72 h. The screening of formulations was performed by considering the drug content within the nanosize range. The best formulation (IVM:T80:PVP 1:0.5:0.5 wt%) was characterized in terms of the particle size distribution, morphology, crystallinity, drug content, and in vitro dissolution profile. This NS was also evaluated from a stability point of view, by conditioning samples at a constant temperature and relative humidity for six months. The fresh and conditioned best NSs Z-sizes were 174.6 and 215.7 nm, respectively; while both NSs showed low polydispersity indexes. The faster dissolution rate for the IVM NS was attributed to the presence of nanoparticles and changes to the crystal structure (i.e. amorphization) that further improved solubility. The best NS had a 4-fold faster initial dissolution rate than raw IVM, and is thus a promising formulation for the treatment of human and animal parasitic diseases.

Carboxyl-functionalized graphene oxide composites as SPR biosensors with enhanced sensitivity for immunoaffinity detection

This work demonstrates the excellent potential of carboxyl-functionalized graphene oxide (GO-COOH) composites to form biocompatible surfaces on sensing films for use in surface plasmon resonance (SPR)-based immunoaffinity biosensors. Carboxyl-functionalization of graphene carbon can modulate its visible spectrum, and can therefore be used to improve and control the plasmonic coupling mechanism. The binding properties of the molecules between a sensing film and a protein were elucidated at various flow rates of those molecules. The bio-specific binding interaction among the molecules was investigated by performing an antigen and antibody affinity immunoassay. The results thus obtained revealed that the overall affinity binding value, K_A, of the Au/GO-COOH chip can be significantly enhanced by up to ∼5.15 times that of the Au/GO chip. With respect to the shifts of the SPR angles of the chips, the affinity immunoassay interaction at a BSA concentration of 1μg/ml for an Au/GO-COOH chip, an Au/GO chip and a traditional SPR chip are 35.5m°, 9.128m° and 8.816m°, respectively. The enhancement of the antigen-antibody interaction of the Au/GO-COOH chip cause this chip to become four times as sensitive to the SPR angle shift and to have the lowest antibody detection limit of 0.01pg/ml. These results indicate the potential of the chip in detecting specific proteins, and the development of real-time in vivo blood analysis and diagnosis based on cancer tumor markers.

Ethyl cellulose nanoparticles as a platform to decrease ulcerogenic potential of piroxicam: formulation and in vitro/in vivo evaluation

Nanoparticles (NPs) have long gained significant interest for their use in various drug formulations in order to increase bioavailability, prolong drug release, and decrease side effects of highly toxic drugs. The objective of this investigation was to evaluate the potential of ethyl cellulose-based NPs (EC-NPs) to modulate the release and reduce ulcerogenicity of piroxicam (PX) after oral administration. PX-loaded EC-NPs were prepared by solvent evaporation technique using different stabilizers at three concentration levels. Morphological examination of selected formulas confirmed the formation of spherical NPs with slightly porous surface. Formulation containing poloxamer-stabilized EC-NPs (P188/0.2), having a particle size of 240.26±29.24 nm, polydispersity index of 0.562±0.030, entrapment efficiency of 85.29%±1.57%, and modulated release of PX (88% after 12 hours), was selected as the optimum formulation. Differential scanning calorimetry demonstrated the presence of PX in an amorphous form in the NPs. Fourier-transform infrared spectroscopy revealed the possible formation of hydrogen bond and the absence of chemical interaction. In vivo study, evaluation of pharmacokinetic parameters, evaluation of gastric irritation potential, and histological examination were conducted after administration of the selected formulation. Time to reach maximum plasma concentration, t_max, of poloxamer-stabilized EC-NPs was significantly higher than that of Feldene^® 20 mg capsules (P≤0.001). Encapsulation of the acidic, gastric offender PX into NPs managed to significantly suppress gastric ulceration potential in rats (P≤0.05) as compared to that of PX suspension. A reduction of 66% in mean ulcer index was observed. In conclusion, poloxamer-stabilized EC-NPs (P188/0.2) had a significant potential of offsetting deleterious side effects common in PX use.

Diclofenac acid nanocrystals as an effective strategy to reduce in vivo skin inflammation by improving dermal drug bioavailability

In this work a diclofenac acid nanosuspension formulation was produced as a novel approach for the treatment of skin inflammation. Drug nanocrystals, prepared by the wet media milling technique and stabilized using Poloxamer 188, were characterized by different techniques: scanning electron microscopy, differential scanning calorimetry, X-ray powder diffractometry, Fourier transform infrared spectroscopy and photon correlation spectroscopy. The ability of nanocrystals to improve dermal drug bioavailability was investigated ex vivo by using Franz diffusion vertical cells and mouse skin, in comparison with both diclofenac acid coarse suspensions and a commercial formulation. The topical anti-inflammatory activity of the drug nanosuspension was assessed in vivo by testing its effect compared to common inflammatory endpoints: i.e. the inhibition of chemically induced oedema and leucocyte infiltration (reflected in myeloperoxidase activity). Following the milling procedure, diclofenac nanocrystals exhibited a mean diameter of approximately 279nm, a low polydispersity index (∼0.17) and maintained the same polymorphic form of the starting bulk powder. When the drug nanosuspension was applied on the mouse skin it produced a higher accumulation of diclofenac in the skin compared to both the coarse suspensions and the commercial formulation, as demonstrated by ex vivo transdermal delivery experiments. Moreover, the nanosuspension provided an in vivo oedema inhibition of 50%, which was not statistically different from the commercial formulation. On the contrary, the nanosuspension showed a higher inhibition of myeloperoxidase activity in the damaged tissue (86%) than the commercial formulation (16%).

Optimization of the sonication process for meloxicam nanocrystals preparation

Background and aims

Meloxicam, a widely recommended AINS, presents poor water solubility, which limits its bioavailability and effect onset. The objective of this study is the investigation of the most important factors that influence the efficiency of sonication in the preparation of meloxicam nanocrystals.

Methods

The effects of crucial technological sonication parameters (amplitude, time and applied cycle) on the crystal sizes and dissolution were investigated using a central composite experimental design with three factors and three levels. Different mathematical models were applied for the evaluation of the influence of each factor on the measured responses.

Results

The amplitude and the time were found as the most important variables. Their increase determined significant size reduction and homogeneity due to cavitation phenomenon, while the applied cycle was less important. The crystal size greatly influenced dissolution; a strong correlation was noted between small crystals and fast dissolution after freeze-drying the nanosuspensions. The optimal formulation was obtained by sonication at 100% amplitude, for 45 minutes and cycle 1, conditions which led to 600 nm crystals with 0.521 polydispersion index. The morphological analysis revealed small, round-shaped crystals with narrow size distribution.

Conclusions

The results provided the optimal sonication conditions needed to obtain meloxicam nanosuspensions with high drug dissolution capacity.

The construction of puerarin nanocrystals and its pharmacokinetic and in vivo-in vitro correlation (IVIVC) studies on beagle dog

Puerarin is widely used in clinics in China as a therapeutic agent for cardiovascular diseases by intravenous administration. Adverse drug reactions caused by cosolvents often increase the patients' treatment burden (high drug costs and low compliance). The development of oral formulation is urgently needed and nanocrystal technique has become a preferred way to develop oral dosage form, nowadays. In this study, high pressure homogenization (HPH) was employed to prepare puerarin nanocrystals by employing SDS as the stabilizer, and redispersibility of the nanocrystals powder was also studied. The nanocrystals prepared was characterized using DLS, DSC, XRD and SEM. A preferred in vivo-in vitro correlation was also established in this study. Pharmacokinetic studies on beagle dog showed that comparing to raw puerarin powder, both of the Cmax and AUC of puerarin nanocrystals were enhanced. From the above results, we can conclude that nanocrystal technique is an efficient technology to improve the oral bioavailability of puerarin.

Solidification drug nanosuspensions into nanocrystals by freeze-drying: a case study with ursodeoxycholic acid

To elucidate the effect of solidification processes on the redispersibility of drug nanocrystals (NC) during freeze-drying, ursodeoxycholic acid (UDCA) nanosuspensions were transformed into UDCA-NC via different solidification process included freezing and lyophilization. The effect of different concentrations of stabilizers and cryoprotectants on redispersibility of UDCA-NC was investigated, respectively. The results showed that the redispersibility of UDCA-NC was RDI-20 °C < RDI-80 °C < RDI-196 °C during freezing, which indicated the redispersibility of UDCA-NC at the conventional temperature was better more than those at moderate and rigorous condition. Compared to the drying strengthen, the employed amount and type of stabilizers more dramatically affected the redispersibility of UDCA-NC during lyophilization. The hydroxypropylmethylcellulose and PVPK30 were effective to protect UDCA-NC from damage during lyophilization, which could homogeneously adsorb into the surface of NC to prevent from agglomerates. The sucrose and glucose achieved excellent performance that protected UDCA-NC from crystal growth during lyophilization, respectively. It was concluded that UDCA-NC was subjected to agglomeration during solidification transformation, and the degree of agglomeration suffered varied with the type and the amounts of stabilizers used, as well as different solidification conditions. The PVPK30-sucrose system was more effective to protect UDCA-NC from the damage during solidification process.

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.

Formulation and optimization of a novel oral fast dissolving film containing drug nanoparticles by Box-Behnken design-response surface methodology

OBJECTIVE

The purpose of this study was to design and optimize a novel drug nanoparticles-loaded oral fast dissolving film (NP-OFDF) using Box-Behnken design-response surface methodology.

METHODS

Drug nanosuspensions produced from high pressure homogenization were transformed into oral fast dissolving film containing drug nanoparticles by casting methods. Herpetrione (HPE), a novel and potent antiviral agent with poor water solubility that was extracted from Herpetospermum caudigerum, was studied as the model drug. The formulations of oral fast dissolving film containing HPE nanoparticles (HPE-NP-OFDF) were optimized by employing Box-Behnken design-response surface methodology and then systematically characterized.

RESULTS

The optimized HPE-NP-OFDF was disintegrated in water within 20 s with reconstituted nanosuspensions particle size of 299.31 nm. Scanning electron microscopy (SEM) images showed that well-dispersed HPE nanoparticles with slight adhesion to each other were exposed on the surface of film or embedded in film. The X-ray diffractogram (XRD) analysis suggested that HPE in the HPE-NP-OFDF was in the amorphous state. In-vitro release study, approximate 77.23% of HPE was released from the HPE-NP-OFDF within 5 min, which was more than eight times compared with that of HPE raw materials (9.57%).

CONCLUSION

The optimized HPE-NP-OFDF exhibits much faster drug release rates compared to HPE raw material, which indicated that this novel NP-OFDF may provide a potential opportunity for oral delivery of drugs with poor water solubility.

Formulation and in vitro evaluation of fast dissolving tablets of metoprolol tartrate

The demand for fast dissolving tablets has been growing during the last decade, especially for elderly and children who have swallowing difficulties. In the present work, fast dissolving tablets of metoprolol tartrate, were prepared using sodium starch glycolate, sodium croscarmellose and crospovidone as superdisintegrants, by the direct compression method. The tablets prepared were evaluated for various parameters including weight variation, hardness, friability, in vitro dispersion time, drug-polymer interaction, drug content water absorption ratio, wetting time, in vitro drug release, FTIR and DSC studies. The tablets prepared by the direct compression method had a weight variation in the range of 145 mg to 152 mg, which is below ± 7.5%, a hardness of 3.6 kg/cm² to 4.5 kg/cm², percentage friability of 0.46% to 0.73%, in vitro dispersion time of 18 s to 125 s, drug content uniformity of between 98.12% and 100.03%, a water absorption ratio of 67% to 87%, wetting time of 32 sec. to 64 sec., and an in vitro drug release of 53.92% - 98.82% within 15 min. The IR spectral analysis and DSC study showed no drug interaction with formulation additives of the tablet, and the formulations indicated no significant changes in hardness, friability, drug content or in vitro drug release. Fast dissolving tablets of metoprolol tartrate have enhanced dissolution and will lead to improved bioavailability and more effective therapy.