Effect of ultrasound on the physico-chemical properties of poorly soluble drugs: Antisolvent sonocrystallization of ketoprofen

Extraction from different parts of Citrus maxima flowers using ultrasound as an aid and study of their composition and function

Ultrasonic assisted extraction is frequently referred to as a green environmental protection method. The flower of Citrus maxima (FCM) has been used as a health tea drink in China, although the tea drink lacks clear compound composition identification and functional research. In order to fully use Citrus fruit by-products and further explore the functional features of FCM, this paper isolated, identified, and assessed the chemical compounds in the petals, stems, styles, receptacles, stamens, and buds of FCM extract. There are 88 compounds were recovered, including 23 compounds in the bud, 21 compounds in the petal, 19 compounds in the stem, 11 compounds in the receptacle, 20 compounds in the stamen, and 13 compounds in the style. Antioxidant experiments revealed that the FCM's various compounds had observable impacts in scavenging free radicals (38.44%-58.35%). The aforementioned study demonstrates that the pomelo by-products were developed into useful components using ultrasonic aided extraction technique. FCM has flavor-rich compounds that make it suited for use as an antioxidant tea beverage and offers practical suggestions for preparing healthy products.

Anti-solvent precipitation for the preparation of nobiletin nano-particles under ultrasonication-cis/reverse homogenization

In order to address the issue of nobiletin's limited bioavailability, nobiletin nanoparticles (NNP) were created for the first time in this research employing an anti-solvent under ultrasonication-cis/reverse homogenization. Dimethyl sulfoxide (DMSO) was used as the solvent and deionized water as the anti-solvent to create the nobiletin solution. The optimal surfactant dose of surfactant dose of 0.43%; an ultrasonic period of 8.1 min, ultrasonic at a temperature of 64 °C and a solution concentration of 8.33 mg/mL, the method was optimized to obtain the minimum NNP diameter of 199.89 ± 0.02 nm. A dual optimization process of response surface PBD and BBD was used to minimize the size of HNP particles. Additionally, scanning electron microscopy revealed that the specific surface area of the NNP dramatically increased with the reduction of NNP particle size, and dissolving studies indicated the solubility and dissolution studies showed that NNP had substantially greater solubility and dissolution rates than raw nobiletin per unit time; as a result, the NNP produced by anti-solvent precipitation with a twofold homogenization system supported by ultrasound had a realistic potential for growth.

Development of eplerenone nano sono-crystals using factorial design: enhanced solubility and dissolution rate via anti solvent crystallization technique

OBJECTIVE

The purpose of this work was to improve EP solubility by using a sono-crystalization approach to reduce particle size and hence, increase the dissolution rate. Significance Eplerenone (EP) is an antagonist of the aldosterone receptor and is used for the treatment of hypertension and chronic heart failure. EP was classed as biopharmaceutical classification (BCS) class II because of its poor solubility and high permeability, which retards dissolution rate and drug absorption, and decreases bioavailability.

METHODS

Three-factors and two-level (2³) multifactorial design have been employed to study the effect of independent variables which are drug concentration; (X1), stabilizer type (X2), and stabilizer concentration (X3) on responses; saturated solubility of EP in distilled water (Y1), saturated solubility in acidic media pH 1.2 (Y2), particle size (Y3), and polydispersity index, PDI (Y4). Also, they were characterized by Fourier transformed infrared spectroscopy (FTIR), Powder X-ray diffraction (PXRD), Differential scanning calorimetry (DSC), and yield percentage. The optimum formula was further subjected to an in-vitro release study.

RESULTS

The optimized formulation showed a saturated solubility of EP as 1.29, and 1.86 (mg/ml) in distilled water and acidic media (pH 1.2) respectively. Also, the particle size of 133 nm, and PDI of 0.824 with a small percentage of the difference between the observed and predicted values. Ninety-one percent of EP was released within 10 min., and it was completely released within 45 min. with a significantly higher release rate compared to raw drug.

CONCLUSION

This work resulted in a satisfactory enhancement of solubility and dissolution rate which, is suitable for further in-vivo analysis.

Pharmacokinetics and Anti-Diabetic Studies of Gliclazide Nanosuspension

Gliclazide (GCZ), an antidiabetic medication, has poor solubility and limited oral bioavailability due to substantial first-pass metabolism. Thus, the purpose of the current study was to optimize and formulate a GCZ nanosuspension (NS) employing the antisolvent precipitation technique. A three-factor, three-level Box–Behnken design (BBD) was used to examine the impact of the primary formulation factors (drug concentration, stabilizer, and surfactant %) on particle size. The optimized NS contains 29.6 mg/mL drug, 0.739% lecithin, and 0.216% sodium dodecyl sulfate (SDS). Under scanning microscopy, the topography of NS revealed spherical particles. Furthermore, NS had a much better saturation solubility than the pure material, which resulted in a rapid dissolving rate, which was attributed to the amorphous structure and smaller particle size of the NS particles. Studies on intestinal permeability using the in vitro noneverted intestinal sac gut method (duodenum, jejunum, and ileum) and single-pass intestinal permeability (SPIP) techniques showed that the effective permeability was also increased by more than 3 fold. In the pharmacokinetic study, the C_max and AUC_0–t values of NS were approximately 3.35- and 1.9-fold higher than those of the raw medication and marketed formulation (MF). When compared to plain drug and commercial formulations, the antidiabetic efficacy of NS demonstrated that it had a significant impact on lowering glucose levels.

Polymorph control by designed ultrasound application strategy: The role of molecular self-assembly

Molecular self-assembly plays a vital role in the nucleation process and sometimes determines the nucleation outcomes. In this study, ultrasound technology was applied to control polymorph nucleation. For the first time, different ultrasonic application methods based on the nucleation mechanisms have been proposed. For PZA-water and DHB-toluene systems that the molecular self-assembly in solution resembles the synthon in crystal structure, ultrasound pretreatment strategy was conducted to break the original molecular interactions to alter the nucleated form. When the solute molecular self-associates can't give sufficient information to predict the nucleated polymorph like INA-ethanol system, the method of introducing continuous ultrasonic irradiation in the nucleation stage was applied. The induction of ultrasound during nucleation process can break the original interactions firstly by shear forces and accelerate the occurrence of nucleation to avoid the reorientation and rearrangement of solute molecules. These strategies were proved to be effective in polymorph control and have a degree of applicability.

A Systematic Approach to the Development of Cilostazol Nanosuspension by Liquid Antisolvent Precipitation (LASP) and Its Combination with Ultrasound

Nanosizing is an approach to improve the dissolution rate of poorly soluble drugs. The first aim of this work was to develop nanosuspension of cilostazol with liquid antisolvent precipitation (LASP) and its combination with ultrasound. Second, to systematically study the effect of bottom-up processing factors on precipitated particles’ size and identify the optimal settings for the best reduction. After solvent and stabilizer screening, in-depth process characterization and optimization was performed using Design of Experiments. The work discusses the influence of critical factors found with statistical analysis: feed concentration, stabilizer amount, stirring speed and ultrasound energy governed by time and amplitude. LASP alone only generated particle size of a few microns, but combination with ultrasound was successful in nanosizing (d10 = 0.06, d50 = 0.33, d90 = 1.45 µm). Micro- and nanosuspension’s stability, particle morphology and solid state were studied. Nanosuspension displayed higher apparent solubility than equilibrium and superior dissolution rate over coarse cilostazol and microsuspension. A bottom-up method of precipitation-sonication was demonstrated to be a successful approach to improve the dissolution characteristics of poorly soluble, BCS class II drug cilostazol by reducing its particle size below micron scale, while retaining nanosuspension stability and unchanged crystalline form.

Preparation of Daidzein microparticles through liquid antisolvent precipitation under ultrasonication

In this study, daidzein microparticles (DMP) were prepared using an improved ultrasound-assisted antisolvent precipitation method. Preliminary experiments were conducted using six single-factor experiments, and principal component analysis (PCA) was adopted to obtain the three staple elements of the ultrasonic power, solution concentration, and nozzle diameter. The response surface Box-Behnken (BBD) design was used to optimize the level of the above factors. The optimal preparation conditions of the DMP were obtained as follows: the flow rate was 4 mL/min, the concentration of the daidzein solution was 16 mg/mL, the ratio of antisolvent to solvent (liquid-to-liquid ratio) was 9, the nozzle diameter was 300 μm, the ultrasonic power was 180 W (665 W/L), and the system speed was 760 r/min. The minimum average particle size of DMP was 181 ± 2 nm. The properties of daidzein particles before and after preparation were analyzed via scanning electron microscopy, X-ray diffraction analysis, Differential scanning calorimetry and Fourier transform infrared spectroscopy, no obvious change in its chemical structure was observed, but crystallinity was reduced. Compared with daidzein powder, DMP has a higher solubility and stronger antioxidant capacity. The above results indicate that the improved method of ultrasonication combined with antisolvent can reduce the size of daidzein particles and has a great potential in practical production.

Sonofragmentation of Organic Molecular Crystals vs Strength of Materials

Mechanochemistry, the interface between the chemical and the mechanical worlds, includes the relationship between the chemical and mechanical properties of solids. In this work, fragmentation of organic molecular crystals during ultrasonic irradiation of slurries has been quantitatively investigated. This has particular relevance to nucleation processes during sonocrystallization, which is increasingly used in the processing and formulation of numerous pharmaceutical agents (PAs). We have discovered that the rates of sonofragmentation are very strongly correlated with the strength of the materials (as measured by Vickers hardness and Young's modulus). This is a mechanochemical extension of the Bell-Evans-Polanyi Principle or Hammond's Postulate: the kinetics (i.e., rates) of solid fracture correlate with thermodynamic properties of solids (e.g., Young's modulus). The mechanism of the particle breakage is consistent with a direct interaction between the shockwaves or localized microjets created by the ultrasound (through acoustic cavitation) and the solid particles in the slurry. Comparisons of the sonofragmentation patterns of ionic and molecular crystals showed that ionic crystals are more sensitive to sonofragmentation than molecular crystals for a given Young's modulus. The rates of sonofragmentation are proposed to correlate with the types and densities of imperfections in the crystals.

Sonocrystallization as an Efficient Way to Control the Size, Morphology, and Purity of Coordination Compound Microcrystallites: Application to a Single-Chain Magnet

The size, morphology, and purity control of coordination compound powders is a key stage for their conversion into materials and devices. In particular, surface science techniques require highly pure bulk materials with a narrow crystallite-size distribution together with straightforward, scalable, and reproducible crystallization procedures. In this work we demonstrate how sonocrystallization, i.e. the application of ultrasound during the crystallization process, can afford very quickly powders made of crystallites with controlled size, morphology, and purity. We show that this process drastically diminishes the crystallite-size distribution (low polydispersity indexes, PDI) and crystallite aspect ratio. By comparing sonicated samples with samples obtained by various silent crystallization conditions, we unambiguously show that the improvement in the crystallite morphology and size distribution is not due to any thermal effect but to the sonication of the crystallizing media. The application of sonocrystallization on crystallization batches of single-chain magnets (SCMs) maintains the chemical integrity of the SCMs together with their original magnetic behavior. Moreover, luminescent measurements show that sonocrystallization induces an efficient micromixing that drastically enhances the purity of the SCM powders. We thus propose that sonocrystallization, which is already used on organic or MOF compounds, can be applied to (magnetic) coordination compounds to readily afford bulk powders for characterization or shaping techniques that require pure, morphology- and crystallite-size-controlled powder samples.

Crystallization of α-glycine by anti-solvent assisted by ultrasound

Crystallization of α-glycine by addition of an anti-solvent (ethanol) assisted by ultrasound is studied. The experiments of crystallization are conducted at 303.15 K in a solution of 150 ml with continuous agitation by a magnetic rod. Ultrasound is then applied at powers ranging from 8 to 41 W thanks to an ultrasonic horn at 20 kHz. The supersaturation ratio (S) is followed throughout all the experiment. At the end of the experiment, the suspension is filtered, the solid is washed with ethanol and dried at 333.15 K. The resulting crystals are characterized by their final size distributions measured by laser granulometry, their morphologies observed by scanning electronic microscope (SEM) and their crystalline structures by differential scanning calorimetry (DSC). The influence of ultrasonic power (continuous 13, 28 and 40 W or pulsed modes), measured by calorimetry method, is studied for different addition rates (0.05 to 0.36 g of ethanol/min). Ultrasound permits to reduce the metastable zone width and to decrease the size of crystals due to an increase of the nucleation rate. The rate of de-supersaturation is higher in presence of ultrasound, inducing a higher nucleation rate, a higher growth rate or both. At 40 W, the decrease of supersaturation is faster, and the crystallization is finished in 40 min instead of 80 min (at 13 and 28 W) or 120 min without ultrasound. The use of pulsed ultrasound (50 on/50 off) is interesting from an economic point of view because similar results are obtained: comparable size distributions and resembling concentration profiles.

The use of ultrasound in the crystallization process of an active pharmaceutical ingredient

In this research, ultrasound was used in the crystallization process as an alternative to conventional spontaneous crystallization and seeding crystallization. The study was implemented on an active pharmaceutical ingredient ticagrelor, where the influence of ultrasound on its physical properties was evaluated. Process parameters of spontaneous crystallization, seeding crystallization and ultrasound-assisted crystallization were extensively studied while the pros and cons of each were adequately exposed. Compared to spontaneous crystallization and seeding crystallization ultrasound-assisted crystallization has significantly improved fundamental crystallization parameters: nucleation, the growth of crystals and filtration time. At the same time, the tendency of particles to agglomerate was reduced, which lead to the avoidance of energy and time-consuming process of final product deagglomeration, often problematic in conventional crystallization. In addition, different physical properties of ticagrelor were reached and evaluated, for instance, morphology, particle size distribution and different polymorphic forms. Polymorphic forms I, II and III were efficiently produced in a repeatable, robust and optimal way. Ultrasound-assisted crystallization was proved to have a beneficial effect on the crystallization process of API, even on the industrial scale, and can successfully replace spontaneous crystallization and seeding crystallization.

Enhancement of the apparent solubility and bioavailability of Tadalafil nanoparticles via antisolvent precipitation

The ability to increase the bioavailability and dissolution of poorly soluble hydrophobic drugs has been a major challenge for pharmaceutical development. This study shows that the dissolution rate, apparent solubility and oral bioavailability of tadalafil (Td) can be improved by nano-sized amorphous particles prepared by using antisolvent precipitation. Acetone and an acetone-water solution (v:v, 9:1) were selected as solvents, with deionized water as the antisolvent. The antisolvent precipitation process was conducted at a constant drug concentration of 10 mg/ml, at temperatures of 5, 10 and 15 °C and at volume ratios of antisolvent to solvent (AS/S) of 5, 8 and 10. Solid dispersion was achieved by dissolving the polymer in the antisolvent prior to the precipitation and by spray drying the suspension after the antisolvent precipitation process. The selected polymers were HPMC, VA64, and PVPK30 at concentrations of 33, 100 and 300 mg per 100 ml of water (equivalent to weight ratios of drug-to-polymer of 1:3, 1:1 and 3:1, respectively). The solid dispersions were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR). The improvements in the dissolution rate, equilibrium solubility, apparent solubility and bioavailability were tested and compared with unprocessed Td. Td particles in the suspension (before spray drying) were 200 nm, and the obtained Td solid dispersion had a size of approximately 5-10 μm. The XRPD, DSC and FT-IR analyses confirmed that the prepared Td particles in the solid dispersions were amorphous. The solid dispersion obtained using the optimized process conditions exhibited 8.5 times faster dissolution rates in the first minute of dissolution, 22 times greater apparent solubility at 10 min and a 3.67-fold increase in oral bioavailability than the as-received Td. The present work demonstrated that low temperature antisolvent precipitation technique has excellent potential to prepare nano-sized amorphous particles with a faster release and a higher bioavailability.

Formulation and Evaluation of Naringenin Nanosuspensions for Bioavailability Enhancement

The clinical potential of naringenin (NRG) is compromised due to its poor aqueous solubility and low oral bioavailability. The study is aimed at addressing these issues by means of naringenin nanosuspensions (NRG-NS) formulated using polyvinylpyrrolidone (PVP K-90) as stabiliser via antisolvent sonoprecipitation method. Optimisation of sonication time, drug concentration and stabilisers was done based on particle size. Characterisation of pure NRG and NRG-NS was carried out by scanning electron microscopy, differential scanning calorimetry (DSC), x-ray powder diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). In vitro dissolution, intestinal absorption by non-everted rat intestinal sac model and in situ single pass intestinal perfusion techniques were performed for further investigation. Nanosuspensions prepared using PVP K-90 lead to minimum particle size (117 ± 5 nm) with zeta potential of -14.6 ± 5.6 mV. The particle size was affected by increasing sonication time, concentration of stabiliser and drug. Nanosizing process converted the crystalline drug into amorphous form as predicted from DSC and XRD patterns. FTIR demonstrated the formation of hydrogen bonds between drug and polymer. NRG-NS displayed a higher dissolution amount (91 ± 4.4% during 60 min) compared to NRG powder (42 ± 0.41%). The apparent and effective permeability of NRG-NS was increased as compared to the pure NRG. The in vivo pharmacokinetics demonstrated that the C _max and AUC_0-24 h values of NRG-NS were approximately 2- and 1.8-fold superior than the pure drug. Hence, overall results confirmed nanosuspensions as promising approach for NRG delivery with high absorption in gastrointestinal tract, improved dissolution and oral bioavailability.