A quality-by-design study to develop Nifedipine nanosuspension: examining the relative impact of formulation variables, wet media milling process parameters and excipient variability on drug product quality attributes

Design of Experiments-Driven Optimization of Spray Drying for Amorphous Clotrimazole Nanosuspension

This study employed a Quality by Design (QbD) approach to spray dry amorphousclotrimazole nanosuspension (CLT-NS) consisting of Soluplus® and microcrystallinecellulose. Using the Box-Behnken Design, a systematic evaluation was conducted toanalyze the impact of inlet temperature, % aspiration, and feed rate on the criticalquality attributes (CQAs) of the clotrimazole spray-dried nanosuspension (CLT-SDNS). In this study, regression analysis and ANOVA were employed to detect significantfactors and interactions, enabling the development of a predictive model for the spraydrying process. Following optimization, the CLT-SD-NS underwent analysis using Xraypowder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), Dynamic Scanning Calorimetry (DSC), and in vitro dissolution studies. The resultsshowed significant variables, including inlet temperature, feed rate, and aspiration rate,affecting yield, redispersibility index (RDI), and moisture content of the final product. The models created for critical quality attributes (CQAs) showed statistical significanceat a p-value of 0.05. XRPD and DSC confirmed the amorphous state of CLT in theCLT-SD-NS, and FTIR indicated no interactions between CLT and excipients. In vitrodissolution studies showed improved dissolution rates for the CLT-SD-NS (3.12-foldincrease in DI water and 5.88-fold increase at pH 7.2 dissolution media), attributed torapidly redispersing nanosized amorphous CLT particles. The well-designed studyutilizing the Design of Experiments (DoE) methodology.

Tannic acid coated nanosuspension for oral delivery of chrysin intended for anti-schizophrenic effect in mice

Chrysin is a flavonoid drug with numerous therapeutic activities. It suffers from low intestinal absorption owing to its hydrophobicity. Therefore, the aim of this study is to exploit the efficient technique of nanosuspension (NSP) to formulate chrysin-NSP coated with tannic acid (TA) to improve the solubility and anti-schizophrenic activity of chrysin. A 23 full factorial design was constructed where the independent factors were type of polymer, surfactant concentration (0.5 or 1 %) and the aqueous phase volume (5 or 15 mL), while the dependent responses were the particle size (PS) of the obtained formulation as well as the % chrysin dissolved after 2 h (Q2h). The optimum formulation (NSP-4) composed of 1 % PEG 400 and 1 % Cremophor RH40 in 15 mL aqueous phase. It achieved a PS and Q2h values of 108.00 nm and 38.77 %, respectively. NSP-4 was then coated with TA (TA-coated NSP-4) for further enhancement of chrysin solubility. TA-coated NSP-4 revealed PS and zeta potential values of 150 ± 14 nm and -32.54 ± 2.45 mV, respectively. After 6 h, chrysin dissolved % were 53.97 and 80.22 for uncoated NSP-4 and TA-coated NSP-4, respectively, compared with only 9.47 for free chrysin. The developed formulations and free chrysin were assessed regarding their effect on schizophrenia induced in mice by cuprizone (CPZ). Treatment with the developed formulations and free chrysin ameliorated demyelination and behavioral deficit induced by CPZ via elevating MBP and PI3K/PKC activities as well as reducing GFAP expression levels. The developed formulations and free chrysin inhibited Galactin-3 and TGF-β expressions and stimulated GST antioxidant enzyme. Furthermore, they maintained the balances in glutamatergic and dopaminergic neurotransmission via modulation on neuregulin-1 and alleviated nuclear pyknosis and degeneration in the neurons. The order of activity was: TA-coated NSP-4 > NSP-4 > free chrysin.

Design of High-Payload Ascorbyl Palmitate Nanosuspensions for Enhanced Skin Delivery

A high-payload ascorbyl palmitate (AP) nanosuspension (NS) was designed to improve skin delivery following topical application. The AP-loaded NS systems were prepared using the bead-milling technique, and softly thickened into NS-loaded gel (NS-G) using hydrophilic polymers. The optimized NS-G system consisted of up to 75 mg/mL of AP, 0.5% w/v of polyoxyl-40 hydrogenated castor oil (Kolliphor® RH40) as the suspending agent, and 1.0% w/v of sodium carboxymethyl cellulose (Na.CMC 700 K) as the thickening agent, in citrate buffer (pH 4.5). The NS-G system was embodied as follows: long and flaky nanocrystals, 493.2 nm in size, -48.7 mV in zeta potential, and 2.3 cP of viscosity with a shear rate of 100 s-1. Both NS and NS-G provided rapid dissolution of the poorly water-soluble antioxidant, which was comparable to that of the microemulsion gel (ME-G) containing AP in solubilized form. In an ex vivo skin absorption study using the Franz diffusion cell mounted on porcine skin, NS-G exhibited faster absorption in skin, providing approximately 4, 3, and 1.4 times larger accumulation than that of ME-G at 3, 6, and 12 h, respectively. Therefore, the high-payload NS makes it a promising platform for skin delivery of the lipid derivative of ascorbic acid.

Formulation and Characterization of Ursodeoxycholic Acid Nanosuspension Based on Bottom-Up Technology and Box-Behnken Design Optimization

BACKGROUND

Ursodeoxycholic acid (UDCA) is a therapeutic agent used for the treatment of cholestatic hepatobiliary diseases in pediatric patients. It is a bile acid that presents high lipophilicity, and it belongs to Class II of the Biopharmaceutical Classification System (BCS), which exhibits low water solubility and high intestinal permeability, which leads to poor oral absorption. The objective of this work was to design and optimize UDCA nanosuspensions by means of the precipitation-ultrasonication method to improve the solubility, dissolution, and oral bioavailability of UDCA.

METHODS

A three-level, three-factor Box-Behnken design was used to optimize formulation variables and obtain uniform, small-particle-size UDCA nanosuspensions. The independent variables were: stabilizer percentage (X1), amplitude (X2), and sonication time (X3), and the dependent variable was the particle size (Y1). In the precipitation-ultrasonication method, UDCA was dissolved in acetone:PEG 400 (1:1 v/v) and quickly incorporated into the antisolvent (pre-cooled aqueous dispersion of HPMC E-15 0.3%), by means of intense sonication at 50 W for 5 min, controlling temperature through an ice water bath. The lyophilization efficacy was evaluated by means of a cryoprotective efficacy test, working with 10% maltose at -80 °C. The nanosuspensions were characterized by dynamic light scattering (DLS), X-ray diffraction, and scanning electron microscopy (SEM). The physicochemical stability was determined at 25 °C and 4 °C at 7, 14, 30, and 60 days, and the UDCA content was analyzed via HPLC-UV. An in vitro dissolution assay and an oral bioavailability study were performed in male Wistar rats.

RESULTS

A significant impact was achieved in the optimized nanosuspension with 0.3% (stabilizer), 50 W (amplitude), and 5 min (sonication time), with a particle size of 352.4 nm, PDI of 0.11, and zeta potential of -4.30 mV. It presented adequate physicochemical stability throughout the study and the UDCA content was between 90% and 110%. In total, 86% of UDCA was dissolved in the in vitro dissolution test. The relative oral bioavailability was similar without significant statistical differences when comparing the lyophilized nanosuspension and the commercial tablet, the latter presenting a more erratic behavior. The pharmacokinetic parameters of the nanosuspension and the commercial tablet were Tmax (1.0 ± 0.9 h vs. 2.0 ± 0.8 h, respectively), Cmax (0.558 ± 0.118 vs. 0.366 ± 0.113 µM, respectively), ΔCmax (0.309 ± 0.099 vs. 0.232 ± 0.056, respectively), AUC (4.326 ± 0.471 vs. 2.188 ± 0.353 µg/mL.h, respectively, p < 0.02), and IAUC0-24h (2.261 ± 0.187 µg/mL.h vs. 1.924 ± 0.440 µg/mL.h, respectively).

CONCLUSIONS

The developed nanosuspension presents an appropriate dosage and administration for pediatric patients. On the other hand, it exhibits an adequate absorption and UDCA oral bioavailability.

Optimization of In Situ Gel-Forming Chlorhexidine-Encapsulated Polymeric Nanoparticles Using Design of Experiment for Periodontitis

Periodontitis is a chronic inflammatory disease of the gums caused by pathogenic microorganisms damaging and destroying periodontal tissues. Chlorhexidine digluconate (CHX) is a commonly used antimicrobial agent for the treatment of periodontitis. However, it has many drawbacks, such as toxicity due to the high dosage required, low prolonged release, and low adhesion in the periodontal pocket. The objective of this study was to develop and optimize CHX-encapsulated polymeric nanoparticles (NPs) loaded into in situ gel-forming (ISGF) using design of experiment (DoE) to improve the treatment of periodontitis and overcome these limitations. CHX-NPs were optimized from 0.046%w/v chitosan, 0.05%w/w gelatin, and 0.25%w/w CHX. After that, the optimized of CHX-NPs was loaded into a thermosensitive ISGF, which was a mixture of 15%w/v Poloxamer 407 and 1% hydroxypropyl methylcellulose (HPMC). The optimized CHX-NPs, loaded into ISGF, was evaluated by measuring gelling temperature and time, pH, viscosity, compatibility, in vitro drug release, antibacterial activity, cytotoxicity, and stability. The results showed that the size, PDI, and zeta potential of optimized CHX-NPs were 53.07±10.17 nm, 0.36±0.02, and 27.63±4.16 mV, respectively. Moreover, the optimized ISGF loading CHX-NPs showed a gelling temperature at 34.3±1.2°C within 120.00±17.32 s with a pH value of 4.06. The viscosity of the formulations at 4°C was 54.33±0.99 cP. The DSC and FTIR showed no interaction between ingredients. The optimal formulations showed a prolonged release of up to 7 days while providing potential antibacterial activity and were safe for normal gingival fibroblast cells. Moreover, the formulations had high stability at 4°C and 25°C for 3 months. In conclusion, the study achieved the successful development of ISGF loading CHX-NPs formulations for effectiveness use in periodontal treatment.

Strategizing Spray Drying Process Optimization for the Manufacture of Redispersible Indomethacin Nanoparticles Using Quality-by-Design Principles

The present study adopted a Quality by Design (QbD) approach to spray dry indomethacin nanosuspension (IMC-NS) consisting of HPC-SL, poloxamer 407, and lactose monohydrate. The Box-Behnken Design was used to systematically evaluate the effects of inlet temperature, aspiration rate, and feed rate on the critical quality attributes (CQAs) [redispersibility index (RDI; minimize), % yield (maximize), and % release at 15 min (maximize)] of the indomethacin spray dried nanosuspension (IMC-SD-NS). To identify significant main and quadratic effects, two-way interactions, and create a predictive model for the spray drying process, regression analysis and ANOVA were utilized. Following optimization, the IMC-SD-NS was analyzed for its physicochemical properties using X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. Statistical analysis revealed significant independent variables, including inlet temperature, feed rate, and aspiration rate, that critically impacted the solidified end product's RDI, % yield, and % release at 15 min. The models developed for critical quality attributes (CQAs) were significant at a p-value of 0.05. The crystalline state of IMC was maintained in the solidified product, as confirmed by XRPD, and no interactions were observed between IMC and the excipients as evaluated by FTIR. In vitro dissolution studies showed improved dissolution rate for the IMC-SD-NS (3.82-fold increase in overall drug release), which may be attributed to the readily redispersible nanosized drug particles. The implementation of a well-designed study, utilizing Design of Experiments (DoE) methodology, played a crucial role in the development of a highly effective spray drying process.

The Preparation of Apigenin Nanoparticles and the Study of Their Anti-Inflammatory and Anti-Tumor Activities In Vitro

Apigenin (API) has many biological activities, but its poor solubility limits its clinical application. In this research, API nanoparticles were prepared by the liquid antisolvent precipitation (LAP) technique, which effectively improved the solubility and bioavailability of API. Through the design of a single-factor test, the effects of the type and dosage of surfactants, API concentration, the antisolvent to solvent volume ratio, the speed and time of stirring, the temperature of precipitation, and the dropping speed on the MPS (mean particle size) of API nanosuspension were carried out. The optimum technological conditions were determined as follows: 5 mg/mL of tween 80 as a surfactant, 20 mg/mL of API, an antisolvent/solvent volume ratio of 10, a 1200 r/min stirring speed for 5 min, a 45 °C precipitation temperature, and a 1 mL/min dropping speed. Under the optimum conditions, we obtained API nanosuspension with 170.5 nm MPS and then it was freeze-dried to obtain the API nanoparticles. Moreover, we characterized the API nanoparticles by SEM, FTIR, XRD, DSC, and TG. Results showed that although API nanoparticles transformed into an amorphous form, their internal chemical structure had not been changed and had a higher solubility. Finally, API nanoparticles’ anti-inflammatory activities were evaluated by observing the effect of API on nitric oxide (NO) production and IL-10 production toward RAW264.7 cells induced by lipopolysaccharide (LPS). Moreover, the anti-tumor effect of API was determined by testing cell viability and apoptosis. The results suggested that API nanoparticles exhibited much better anti-inflammatory and anti-tumor activities compared to raw API.

Predicting the Temperature Evolution during Nanomilling of Drug Suspensions via a Semi-Theoretical Lumped-Parameter Model

Although temperature can significantly affect the stability and degradation of drug nanosuspensions, temperature evolution during the production of drug nanoparticles via wet stirred media milling, also known as nanomilling, has not been studied extensively. This study aims to establish both descriptive and predictive capabilities of a semi-theoretical lumped parameter model (LPM) for temperature evolution. In the experiments, the mill was operated at various stirrer speeds, bead loadings, and bead sizes, while the temperature evolution at the mill outlet was recorded. The LPM was formulated and fitted to the experimental temperature profiles in the training runs, and its parameters, i.e., the apparent heat generation rate Q_gen and the apparent overall heat transfer coefficient times surface area UA, were estimated. For the test runs, these parameters were predicted as a function of the process parameters via a power law (PL) model and machine learning (ML) model. The LPM augmented with the PL and ML models was used to predict the temperature evolution in the test runs. The LPM predictions were also compared with those of an enthalpy balance model (EBM) developed recently. The LPM had a fitting capability with a root-mean-squared error (RMSE) lower than 0.9 °C, and a prediction capability, when augmented with the PL and ML models, with an RMSE lower than 4.1 and 2.1 °C, respectively. Overall, the LPM augmented with the PL model had both good descriptive and predictive capability, whereas the one with the ML model had a comparable predictive capability. Despite being simple, with two parameters and obviating the need for sophisticated numerical techniques for its solution, the semi-theoretical LPM generally predicts the temperature evolution similarly or slightly better than the EBM. Hence, this study has provided a validated, simple model for pharmaceutical engineers to simulate the temperature evolution during the nanomilling process, which will help to set proper process controls for thermally labile drugs.

The Impact of Process and Formulation Parameters on the Fabrication of Efavirenz Nanosuspension to Improve Drug Solubility and Dissolution

Background

Efavirenz nanosuspensions (EZ-NSs) were developed by the wet milling method as the most promising top-down nanosizing technique. Different process and formulation parameters were studied and optimized to produce appropriate EZ-NS in suitable conditions to enhance drug dissolution.

Methods

In the preliminary studies, various polymeric stabilizers, including Pluronic F68, sodium carboxymethylcellulose (CMC), hydroxypropyl methylcellulose (HPMC), and polyvinyl alcohol (PVA), as well as different sizes and weight of milling beads were used to prepare NSs. The effect of sodium lauryl sulfate (SLS) concentration on the NS properties was also evaluated. The influence of other formulation and process parameters, including polymer concentration, milling speed, and milling time, on the particle size and distribution of NSs were investigated using Box-Behnken design. The optimized freeze-dried nanosuspension was characterized by redispersibility, physicochemical properties, and stability.

Results

A combination of PVA and SLS was selected as steric and electrostatic stabilizers. The optimum EZ-NS displayed a uniform size distribution with a mean particle size and zeta potential of 254.4 nm and 21.1 mV, respectively. The solidified nanosuspension was well redispersed to the original nanoparticles. Significantly enhanced aqueous solubility (about 11-fold) and accelerated dissolution rate were observed for the optimized formulation. This could be attributed to the reduced particle size and partial amorphization of EZ during the preparation process, studied by X-ray diffraction. Accelerated studies confirmed the stability of the optimum freeze-dried formulation over the examined period of three months.

Conclusions

Optimization of different variables led to the formation of EZ-NSs with desired properties through wet milling in a very short time compared to the previous study and therefore reduced production costs. This formulation seems to be a suitable approach for solubility and dissolution enhancement of EZ and may have a great potential to improve the drug's oral bioavailability.

An Enthalpy-Balance Model for Timewise Evolution of Temperature during Wet Stirred Media Milling of Drug Suspensions

PURPOSE

Nanosuspensions have been used for enhancing the bioavailability of poorly soluble drugs. This study explores the temperature evolution during their preparation in a wet stirred media mill using a coupled experimental-enthalpy balance approach.

METHODS

Milling was performed at three levels of stirrer speed, bead loading, and bead sizes. Temperatures were recorded over time, then simulated using an enthalpy balance model by fitting the fraction of power converted to heat ξ. Moreover, initial and final power, ξ, and temperature profiles at 5 different test runs were predicted by power-law (PL) and machine learning (ML) approaches.

RESULTS

Heat generation was higher at the higher stirrer speed and bead loading/size, which was explained by the higher power consumption. Despite its simplicity with a single fitting parameter ξ, the enthalpy balance model fitted the temperature evolution well with root mean squared error (RMSE) of 0.40-2.34°C. PL and ML approaches provided decent predictions of the temperature profiles in the test runs, with RMSE of 0.93-4.17 and 1.00-2.17°C, respectively.

CONCLUSIONS

We established the impact of milling parameters on heat generation-power and demonstrated the simulation-prediction capability of an enthalpy balance model when coupled to the PL-ML approaches.

Analysis of heat generation during the production of drug nanosuspensions in a wet stirred media mill

Although heat is generated during the wet stirred media milling of drug suspensions, leading to notable temperature rise, a comprehensive analysis of heat generation does not exist. Hence, we investigated the impact of stirrer speed, bead loading, and bead size at three levels on the evolution of suspension temperature at the mill outlet during the milling of fenofibrate. The particle sizes and viscosities of the milled suspensions and power were measured. Our results suggest that stirrer speed had the most significant impact on the temperature increase, followed by bead loading and bead size. Both the time when the temperature reached 22 °C and the temperature at 5 min of milling were strongly correlated with the power. Assessing the impacts of the process parameters on the temperature rise, cycle time, power, and median particle size holistically, an optimal milling process was identified: 3000 rpm with 50% loading of 200 or 400 µm beads. A power number correlation was established to calculate power at any milling condition which determines the heat generation rate. Overall, this study indicated the importance of developing a good understanding of heat generation during nanomilling for development of a robust milling process especially for thermally labile drugs.

Betamethasone Dipropionate Nanocrystals: Investigation, Feasibility and In Vitro Evaluation

Corticosteroids, such as betamethasone dipropionate (BMD), have been the mainstay in topical therapy as potent glucocorticoid receptor agonist with immune suppression, anti-proliferative, and anti-inflammatory effects. Moreover, they have poor skin penetration, which is a hurdle against its potential therapeutic benefits. In present investigation, nanocrystals as carrier for effective topical delivery of BMD were explored using wet milling as technique and polysorbate 80 as a non-ionic stabilizer. Upon optimizing different process parameters, promising results were observed at stabilizer concentration of 0.9% w/v having particle size analysis (PSA) and PDI as 284 nm and 0.299, respectively. These results were supported by the FTIR and PXRD spectra of BMD-API and BMD nanocrystals, suggesting strong crystal lattice structure of BMD being reduced due to milling. The reduction in particle morphology was evident from the FESEM images. The optimized batch of BMD nanocrystals was incorporated into Carbopol gel base, showing pH 6.2 ± 0.2 and viscosity 87.00 ± 5.2 Pa s at 25°C. A drug diffusion study using Franz diffusion cell proclaimed around ~86% BMD release from nanogel across the membrane. Also, it was observed that the BMD permeation across the skin was 2.39-fold higher with marketed formulation in contrast to BMD nanogel, suggesting prolonged drug release. The skin permeation flux with nanogel was at a much lower rate along with ~50.27% drug retention in different strata of skin, resulting in retention of drug nanocrystals. Thus, in nutshell the prolonged drug release from nanogel would fulfill the aim of once a day application and would aid in reducing the adverse events associated with repeated drug applications.

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.

Can the cavi-precipitation process be exploited to generate smaller size drug nanocrystal?

OBJECTIVE

Cavi-precipitation has the potential to generate drug nanocrystals very efficiently. Achieving smaller than 100 nm particle size for organic drug substances still remained a challenge. The objective of this study was to demonstrate if cavi-precipitation technology can be used to generate smaller than 100 nm drug nanocrystal particle.

SIGNIFICANCE

This study demonstrates that cavi-precipitation process can be used to generate drug nanocrystals of the model compound resveratrol (RVT) consists of crystallites of 30-50 nm size.

METHOD

RVT was dissolved in different organic solvents to prepare the solvent phase (S-phase). Several stabilizers were tested for the organic phase. A combination of SDS and PVP was used stabilizer system in the aqueous anti-solvent phase (AS-phase). The S-phase was added to the AS-phase inside the Emulsiflex C5 homogenizer. Nanosuspension was characterized by laser diffractometry (LD), photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The solid state of the suspended particles was investigated by powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC).

RESULTS

It was found that DMSO, alone or in combination with acetone in the S-Phase generated the smallest size RVT nanocrystals. The optimum solvent (S) antisolvent (AS) ratio (S:AS) was found to be 3.6:56.4 (v:v). Span 20 was identified as the best stabilizer for the organic phase at a ratio (w:w) of 1:3 (Span 20:RVT). The particles precipitated from different solvents were predominantly crystalline.

CONCLUSIONS

The best sample had a mean particle size (LD) of 167 nm [d(0.5)] which was composed of smaller crystallites having 30-50 nm size (SEM).

Improving Breviscapine Oral Bioavailability by Preparing Nanosuspensions, Liposomes and Phospholipid Complexes

Breviscapine (BVP), a flavonoid compound, is widely used in the treatment of cardiovascular and cerebrovascular diseases; however, the low oral bioavailability and short half-life properties limit its application. The aim of this study was to investigate the three preparations for improving its oral bioavailability: nanosuspensions (BVP-NS), liposomes (BVP-LP) and phospholipid complexes (BVP-PLC). In vitro and in vivo results suggested that these three could all significantly improved the cumulative released amount and oral bioavailability compared with physical mixture, in which BVP-PLC was the most optimal preparation with the relative bioavailability and mean retention time of 10.79 ± 0.25 (p < 0.01) and 471.32% (p < 0.01), respectively. Furthermore, the influence of drug-lipid ratios on the in vitro release and pharmacokinetic behavior of BVP-PLC was also studied and the results showed that 1:2 drug-lipid ratio was the most satisfactory one attributed to the moderate-intensity interaction between drug and phospholipid which could balance the drug loading and drug release very well.

Mechanistic Modeling of Wet Stirred Media Milling for Production of Drug Nanosuspensions

Drug nanocrystals have been used for a wide range of drug delivery platforms in the pharmaceutical industry, especially for bioavailability enhancement of poorly water-soluble drugs. Wet stirred media milling (WSMM) is the most widely used process for producing dense, stable suspensions of drug nanoparticles, also referred to as nanosuspensions. Despite a plethora of review papers on the production and applications of drug nanosuspensions, modeling of WSMM has not been thoroughly covered in any review paper before. The aim of this review paper is to briefly expose the pharmaceutical scientists and engineers to various modeling approaches, mostly mechanistic, including computational fluid dynamics (CFD), discrete element method (DEM), population balance modeling (PBM), coupled methods, the stress intensity-number model (SI-SN model), and the microhydrodynamic (MHD) model with a main focus on the MHD model for studying the WSMM process. A total of 71 studies, 30 on drugs and 41 on other materials, were reviewed. Analysis of the pharmaceutics literature reveals that WSMM modeling is largely based on empirical, statistically based modeling approaches, and mechanistic modeling could help pharmaceutical engineers develop a fundamental process understanding. After a review of the salient features and various pros-cons of each modeling approach, recent advances in microhydrodynamic modeling and process insights gained therefrom were highlighted. The SI-SN and MHD models were analyzed and critiqued objectively. Finally, the review points out potential research directions such as more mechanistic and accurate CFD-DEM-PBM simulations and the coupling of the MHD-PBM models with the CFD.

Nanosuspensions of a poorly soluble investigational molecule ODM-106: Impact of milling bead diameter and stabilizer concentration

Aqueous solubility of a drug substance is an important attribute affecting oral bioavailability. Nanonization, particle size reduction to submicron level, is an elegant approach to improve drug solubility and dissolution by increasing the surface energy, which in turn necessitates the use of stabilizers. The purpose of this study was to develop a nanosuspension of a practically water-insoluble investigational molecule by nanomilling approach using wet media milling. A variety of polymeric and surface active excipients were tested for their wettability. A combination of hydroxypropyl methylcellulose and sodium lauryl sulfate (SLS) were selected as stabilizers on the bases of compatibility studies and efficient wettability behaviour in contact angle measurements (≈80˚). A factorial design set-up was used to study the effect of milling bead diameter and stabilizer concentration on the efficiency of particle size reduction. Nanonization outcome was different when milling beads of 0.5 mm and 1 mm diameter were used at different concentrations of the stabilizers, which demonstrated the complex nature of the whole system. Storage of the nanosuspensions under different temperature conditions resulted only in minor changes of the particle size fractions.

Investigation of Formulation and Process Parameters of Wet Media Milling to Develop Etodolac Nanosuspensions

PURPOSE

Etodolac (ETD) is one of the non-steroidal anti-inflammatory drugs which has low aqueous solubility issues. The objective of this study was to develop ETD nanosuspensions to improve its poor aqueous solubility properties while investigating formulation and process parameters of wet media milling method via design of experiment (DoE) approach.

METHODS

The critical formulation parameters (CFP) were selected as ETD amount, stabilizer type and ratio as well as critical process parameters (CPP) which were bead size, milling time and milling speed. The two-factorial-2³ and The Box-Benkhen Designs were generated to evaluate CFP and CPP, respectively. Particle size (PS), polydispersity index (PDI) and zeta potential (ZP) were analyzed as dependent variables. Characterization, physical stability and solubility studies were performed.

RESULTS

Optimum nanosuspensions stabilized by PVP K30 and Poloxamer 188 showed 188.5 ± 1.6 and 279.3 ± 6.1 nm of PS, 0.161 ± 0.049 and 0.345 ± 0.007 PDI, 14.8 ± 0.3 and 16.5 ± 0.4 mV of ZP values, respectively. The thermal properties of ETD did not change after milling and lyophilization process regarding to DSC analysis. Also, the crystalline state of ETD was preserved. The morphology of particle was smooth and spherical on SEM. The dry-nanosuspensions stayed physically stable for six months at room temperature. The solubility of nanosuspensions increased up to 13.0-fold in comparison with micronized ETD.

CONCLUSIONS

In conclusion, it is found that the poor solubility issue of ETD can be solved by nanosuspension. DoE approach provided benefits such as reducing number of experiments, saving time and improving final product quality by using wet media milling.

Preparation and characterisation of tetrandrine nanosuspensions and in vitro estimate antitumour activity on A549 lung cancer cell line

Aim: The aim of this study was to improve solubility and antitumour ability in vitro of tetrandrine (Tet) via preparing nanosuspensions (NSs).Methods: The Tet-NSs were prepared by wet media milling. The Tet-CCS-NS was prepared with croscarmellose sodium (CCS) as single stabiliser. The Tet-HACC-TPGS-NS was manufactured with D-α-tocopheryl polyethylene glycol 1,000 succinate (TPGS) and hydroponically trimethyl ammonium chloride chitosan (HACC) as combined stabilisers. Physicochemical properties of the NSs such as particle size, surface morphologies, crystallinity and molecular interactions were investigated. In addition, the in vitro dissolution and antitumour activities using A549 human lung cancer cells were evaluated.Results: The mean particle sizes and Zeta potential of freshly prepared Tet-CCS-NS, Tet-HACC-TPGS-NS were 469.1 ± 14nm and 157.3 ± 5nm, -29.4 ± 0.26 mV and 23.3 ± 0.36 mV, respectively. In comparison to pure Tet, the cumulative dissolution of Tet-NSs were increased by 4 ∼ 5 times in 2 h. In vitro antitumour studies on Tet- NSs in A549 cells, the cell survival rate of the Tet-NSs at high concentration (30-50µg/ml) were less than 10% within 48 h. Meanwhile, Tet-NSs were revealed to induce A549 cells apoptosis and promote cell uptake.Conclusion: The present study has proved that the Tet-NSs can increase Tet solubility as well as improve Tet antitumour activity in vitro.

Development and evaluation of TPGS/PVA-based nanosuspension for enhancing dissolution and oral bioavailability of ticagrelor

In this study, we developed ticagrelor-dispersed nanosuspension (TCG-NSP) to enhance the dissolution and oral bioavailability of ticagrelor (TCG) through a statistical design approach. TCG, a reversible P2Y₁₂ receptor antagonist, is classified as a biopharmaceutics classification system (BCS) class IV drug with low solubility and permeability, resulting in low oral bioavailability. Nanosuspension (NSP) is an efficient pharmaceutical technique for overcoming the disadvantages. First, we optimized TCG-NSP consisting of D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) and polyvinyl alcohol (PVA), which exhibited homogeneously dispersed TCG particle (233 nm) and low precipitation (3%). Characterization studies demonstrated that TCG-NSP provided amorphous TCG particles and supersaturation effect, resulting in higher dissolution than a commercial product. In addition, everted gut sac and pharmacokinetic studies confirmed that TCG-NSP improved the gastrointestinal permeation of TCG by 2.8-fold compared to commercial product, thereby enhancing the oral bioavailability (2.2-fold). These results suggested that TCG-NSP could be successfully used as an efficient pharmaceutical formulation to achieve the enhanced dissolution and oral bioavailability of TCG.

Design, Preparation, and Characterization of Dioscin Nanosuspensions and Evaluation of Their Protective Effect against Carbon Tetrachloride-Induced Acute Liver Injury in Mice

The purpose of this study was to prepare a dioscin nanosuspension (Dio-NS) that has a better distance and high solubility for oral administration and to evaluate its hepatoprotective effects. Optimal primary manufacture parameters, including shear time, shear speed, emulation temperature, pressure, and cycles of homogenization, were determined by single-factor experiments. The concentrations of dioscin, SDS, and soybean lecithin were optimized using the central composite design-response surface method, and their effects on the mean particle size (MPS) and particle size distribution of Dio-NS were investigated. Characterization of the Dio-NS formulations included examinations of the surface morphology and physical status of dioscin in Dio-NS, the stability of Dio-NS at different temperatures, in vitro solubility, and liver protective effect in vivo. Under optimal conditions, Dio-NS had an MPS of 106.72 nm, polydispersity index of 0.221, and zeta potential of −34.27 mV. Furthermore, the proportion of dioscin in Dio-NS was approximately 21.26%. The observation of particles with a spherical shape and the disappearance of crystalline peaks indicated that the physical and chemical properties of Dio-NS were altered. Furthermore, we observed that the dissolution of Dio-NS was superior to that of a physical mixture and Dio-GZF. Moreover, Dio-NS was demonstrated to have a protective effect against CCl₄-induced acute liver damage in mice that was equivalent to that of silymarin (a positive control drug) at the same dose. The good hepatoprotective effect of our Dio-NS preparation can provide a theoretical basis for investigating its absorption mechanisms in the body.