Formulating food protein-stabilized indomethacin nanosuspensions into pellets by fluid-bed coating technology: physical characterization, redispersibility, and dissolution

Preparation and characterization of soluplus-based nanosuspension for dissolution enhancement of indomethacin using ultrasonic assisted precipitation method for formulation and Box-Behnken design for optimization

OBJECTIVES

Nanosuspensions are increasingly recognized as a valuable technology for enhancing poorly water-soluble drugs' solubility and dissolution rate, thereby improving their bioavailability. In this study, we employed ultrasonic-assisted precipitation to fabricate nanosuspensions of indomethacin (IND), utilizing Soluplus® (Sol) as a stabilizing agent. Our objectives were driven by hypotheses centered on optimizing formulation variables and developing predictive models for optimal IND formulations.

SIGNIFICANCE

This research highlights the Box-Behnken design (BBD) as a powerful tool that optimizes the properties of IND nanosuspensions, thus significantly enhancing their dissolution rate.

METHODS

The impacts of the independent variables on the mean particle size (MPS), polydispersity index (PDI), and zeta potential (ZP) were investigated using BBD. The optimized nanosuspension was freeze-dried with 3% trehalose to produce a dry nanosuspension (DNS). The DNS was characterized by SEM, DSC, XRPD, solubility, and dissolution.

RESULTS

The IND: Sol ratio and sonication power significantly affected the MPS and ZP of the nanosuspensions. The optimized formulation showed MPS, PDI, and ZP of 144.77 ± 6.68 nm, 0.26 ± 0.08, and -24.6 ± 1.90 mV, respectively. The DNS exhibited spherical particle morphology. The DSC and XRPD confirmed the amorphous state of IND with enhanced solubility and dissolution of IND. DNS showed a 3.7-fold increase in drug release in the first 15 min compared with raw IND.

CONCLUSIONS

This study demonstrated the critical role of BBD in accurately predicting the values of independent variables essential for formulating optimal nanosuspensions. These formulations possess specific properties that can be effectively integrated into various dosage forms tailored for different routes of administration.

Nanosuspension: A Formulation Technology for Tackling the Poor Aqueous Solubility and Bioavailability of Poorly Soluble Drugs

The poor water solubility of numerous novel drug candidates presents significant challenges, particularly in terms of oral administration. This limitation can result in various undesirable clinical implications, such as inter-patient variability, poor bioavailability, difficulties in achieving a safe therapeutic index, increased costs, and potential risks of toxicity or inefficacy. Biopharmaceutics Classification System (BCS) class II drugs face particular hurdles due to their limited solubility in the aqueous media of the gastrointestinal tract. In such cases, parenteral administration is often employed as an alternative strategy. To address these challenges, nanosuspension techniques offer a promising solution for enhancing drug solubility and overcoming oral delivery obstacles. This technique has the potential to bridge the gap between drug discovery and preclinical use by resolving problematic solubility. This literature review has delved into contemporary nanosuspension preparation technologies and the incorporation of stabilizing ingredients within the formulation. Furthermore, the manuscript explores nanosuspension strategies for both oral and parenteral/other delivery routes, and separate discussions have been presented to establish a suitable flow that addresses the challenges and strategies relevant to each administration method.

Formulation of Aceclofenac Tablets Using Nanosuspension as Granulating Agent: An Attempt to Enhance Dissolution Rate and Oral Bioavailability

PURPOSE

The aim of the studies was to fabricate aceclofenac (AC) tablets using nanosuspension as granulating fluid to boost its rate of in vitro dissolution and eventually its oral bioavailability.

METHODS

The optimized nanosuspension with particle size of 112±2.01 nm was fabricated using HPMC 1% (w/v), PVP-K30 1% (w/v) and SLS 0.12% (w/v) at 400 watts of ultrasonication energy for 15 min duration and 3 sec pause. Then, the optimized aceclofenac nanosuspension was used as granulating fluid for aceclofenac tablets formulation. The characterization was performed using Malvern zetasizer, SEM, TEM, DSC and P-XRD. The granules were evaluated for the bulk and tapped densities, Hausner's ratio, angle of repose and their resulted values were found within limit. The prepared tablets were tested for average weight, hardness, friability, disintegration, dissolution and in vivo bioavailability in rabbits.

RESULTS

The in vitro dissolution data showed the boosted rate of nanosuspension-based tablets compared to the microsuspension-based tablets. The in vivo bioavailability (in rabbits model) of aceclofenac nanosuspension-based tablets (ACN-1, ACN-2) proved an improved absorption as in comparison to the marketed formulation. The Cmax and AUC0→24 of ACN-1 and ACN-2 were 1.53-fold, 1.48-fold and 2.23-fold, 2.0-fold greater than that of the marketed drug, and were 1.74-fold, 1.68-fold and 2.3-fold, 2.21-fold greater in comparison to raw drug.

CONCLUSION

This boosted in vitro and in vivo bioavailability may be attributed to reduced particle size of aceclofenac nanoformulations used in tablets. Finally, this will result in faster absorption of these fabricated tablets.

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.

Transformation of Meloxicam Containing Nanosuspension into Surfactant-Free Solid Compositions to Increase the Product Stability and Drug Bioavailability for Rapid Analgesia

Purpose

The aim of this work was to study the influence of solidification of meloxicam (Mel) containing nanosuspension (nanoMel) on the physical stability and drug bioavailability of the products. The nanoMel sample had poly(vinyl alcohol) (PVA) as a protective polymer, but no surfactant as a further stabilizing agent because the final aim was to produce surfactant-free solid phase products as well.

Methods

The solidified samples produced by fluidization and lyophilization (fluidMel, lyoMel) were examined for particle size, crystallinity, and in vitro release of Mel compared to similar parameters of nanoMel. The products were subjected to an animal experiment using per oral administration to verify their bioavailability.

Results

Mel containing (1%) nanoMel sample was produced by wet milling process using an optimized amount of PVA (0.5%) which resulted in 130 nm as mean particle size and a significant reduction in the degree of crystallinity (13.43%) of Mel. The fluidization technique using microcrystalline cellulose (MCC) as carrier resulted in a quick conversion and no significant change in the critical product parameters. The process of lyophilization required a longer operation time, which resulted in the amorphization of the crystalline carrier (trehalose) and the recrystallization of Mel increased its particle size and crystallinity. The fluidMel and lyoMel samples had nearly five-fold higher relative bioavailability than nanoMel application by oral administration. The correlation between in vitro and in vivo studies showed that the fixed Mel nanoparticles on the surface of solid carriers (MCC, trehalose) in both the artificial gastric juice and the stomach of the animals rapidly reached saturation concentration leading to faster dissolution and rapid absorption.

Conclusion

The solidification of the nanosuspension not only increased the stability of the Mel nanoparticles but also allowed the preparation of surfactant-free compositions with excellent bioavailability which may be an important consideration for certain groups of patients to achieve rapid analgesia.

Engineering of solidified glyburide nanocrystals for tablet formulation via loading of carriers: downstream processing, characterization, and bioavailability

INTRODUCTION

Presenting poorly water-soluble drugs as nanoparticles has shown to be an effective technique in enhancing drug dissolution rate, intrinsic solubility, and thus oral bioavailability. Nevertheless, working with nanoparticles introduces many challenges, one of which is their physical instability. Formulating nanoparticles into a solid dosage form may overcome such challenges and thus unlock the potential benefits of nanosizing.

METHODS

The current work investigates the possibility of developing a novel solid dosage form, with enhanced dissolution rate, whereby nanocrystals (~400 nm) of the class II Biopharmaceutical Classification System drug, glyburide (GBD) were fabricated through combined precipitation and homogenization procedures. Using a novel, but scalable, spraying technique, GBD nanocrystals were loaded onto commonly used tablet fillers, water-soluble lactose monohydrate (LAC), and water insoluble microcrystalline cellulose (MCC). Conventional tableting processes were then used to convert the powders generated into a tablet dosage form.

RESULTS

Studies of redispersibility showed considerable preservation of size characteristics of GBD nanocrystals during downstream processing with redispersibility indices of 105 and 118 for GBD-LAC and GBD-MCC, respectively. Characterization by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy showed that the powders generated powders contained nanosized crystals of GBD which adhered to carrier surfaces. Powder flowability was characterized using Hausner ratio (HR) and Carr's index (CI). GBD-LAC-loaded particles exhibited poor flowability with CI and HR of 37.5% and 1.60, respectively, whilst GBD-MCC particles showed a slightly improved flowability with CI and HR of 26.47% and 1.36, respectively. The novel tablet dosage form met US Pharmacopeia specifications, including drug content, hardness, and friability.

CONCLUSION

Higher dissolution rates were observed from the nanocrystal-based tablets compared to the microsized and commercial drug formulations. Moreover, the novel nanocrystal tablet dosage forms showed enhanced in vivo performance with area under the plasma concentration- time curve in the first 24 hours values 1.97 and 2.24 times greater than that of marketed tablets.

Enhanced dissolution and oral bioavailbility of cinacalcet hydrochlorde nanocrystals with no food effect

This study was aimed at improving oral bioavailbility and reducing the food effect of cinacalcet hydrochlorde (CINA), a poorly soluble drug for the treatment of chronic kidney disease, by preparing its nanocrystals (NCs) utilizing the precipitation-ultrasonication method. Based on the single factor method and Box-Behnken design, with the particle size and polydispersity index (PDI) as indexes, the optimal formulation was achieved. It was investigated that the particle size and PDI of the NCs prepared on the basis of optimal formulation were 244 ± 2 nm and 0.168 ± 0.001, respectively. The NCs were solidificated by lyophilization. Scanning electron microscopy, differential scanning calorimetry and x-ray powder diffraction were used to characterize the CINA-NCs, and there was no crystalline change during preparation and lyophilization. The CINA-NCs capsules prepared with 30% (w/v) MCC, 8% (w/v) CCNa and 2% (w/v) talcum powder by orthogonal experimental design presented an enhanced in vitro dissolution rate in four media compared with commercial tablets Sensipar® and raw material. The raw material, blank NCs and CINA-NCs were confirmed to be non-toxic to Caco-2 cells when the drug concentration was below 250 μg ml^-1. In the in vivo pharmacokinetic study, the C_max (the peak concentration of CINA in plasma) and AUC_0-t (area under curve by trapezoidal area method) of the CINA-NCs capsules were approximately 1.90-fold and 1.64-fold greater than that of Sensipar® in the fasted state. Overall, this nanotechnology is a promising way to optimize the dosage form of CINA oral administration.

Parenteral nanosuspensions: a brief review from solubility enhancement to more novel and specific applications

Advancements in in silico techniques of lead molecule selection have resulted in the failure of around 70% of new chemical entities (NCEs). Some of these molecules are getting rejected at final developmental stage resulting in wastage of money and resources. Unfavourable physicochemical properties affect ADME profile of any efficacious and potent molecule, which may ultimately lead to killing of NCE at final stage. Numerous techniques are being explored including nanocrystals for solubility enhancement purposes. Nanocrystals are the most successful and the ones which had a shorter gap between invention and subsequent commercialization of the first marketed product. Several nanocrystal-based products are commercially available and there is a paradigm shift in using approach from simply being solubility enhancement technique to more novel and specific applications. Some other aspects in relation to parenteral nanosuspensions are concentrations of surfactant to be used, scalability and in vivo fate. At present, there exists a wide gap due to poor understanding of these critical factors, which we have tried to address in this review. This review will focus on parenteral nanosuspensions, covering varied aspects especially stabilizers used, GRAS (Generally Recognized as Safe) status of stabilizers, scalability challenges, issues of physical and chemical stability, solidification techniques to combat stability problems and in vivo fate.

Bioavailability Enhancement of Poorly Water-Soluble Drugs via Nanocomposites: Formulation⁻Processing Aspects and Challenges

Drug nanoparticles embedded in a dispersant matrix as a secondary phase, i.e., drug-laden nanocomposites, offer a versatile delivery platform for enhancing the dissolution rate and bioavailability of poorly water-soluble drugs. Drug nanoparticles are prepared by top-down, bottom-up, or combinative approaches in the form of nanosuspensions, which are subsequently dried to prepare drug-laden nanocomposites. In this comprehensive review paper, the term “nanocomposites” is used in a broad context to cover drug nanoparticle-laden intermediate products in the form of powders, cakes, and extrudates, which can be incorporated into final oral solid dosages via standard pharmaceutical unit operations, as well as drug nanoparticle-laden strip films. The objective of this paper is to review studies from 2012⁻2017 in the field of drug-laden nanocomposites. After a brief overview of the various approaches used for preparing drug nanoparticles, the review covers drying processes and dispersant formulations used for the production of drug-laden nanocomposites, as well as various characterization methods including quiescent and agitated redispersion tests. Traditional dispersants such as soluble polymers, surfactants, other water-soluble dispersants, and water-insoluble dispersants, as well as novel dispersants such as wet-milled superdisintegrants, are covered. They exhibit various functionalities such as drug nanoparticle stabilization, mitigation of aggregation, formation of nanocomposite matrix⁻film, wettability enhancement, and matrix erosion/disintegration. Major challenges such as nanoparticle aggregation and poor redispersibility that cause inferior dissolution performance of the drug-laden nanocomposites are highlighted. Literature data are analyzed in terms of usage frequency of various drying processes and dispersant classes. We provide some engineering considerations in comparing drying processes, which could account for some of the diverging trends in academia vs. industrial practice. Overall, this review provides rationale and guidance for drying process selection and robust nanocomposite formulation development, with insights into the roles of various classes of dispersants.