Stable Nanosuspension Research Articles

Albendazole nanosuspension coated granules for the rapid localized release and treatment of colorectal cancer

Albendazole (ABZ), an anthelmintic drug, has been repurposed to treat various types of cancers. However, poor solubility of ABZ, resulting in low bioavailability, limits its application. Nanosuspension is a versatile method for enhancing the dissolution of hydrophobic molecules, but a successful drying has been the biggest challenge in the field. The objective of this research is to formulate and optimize ABZ nanosuspension (NS) coated granules for rapid delivery of ABZ for the treatment of colorectal cancer. ABZ NS was prepared by dual centrifugation method using Kollidon® VA64 and sodium lauryl sulphate (SLS) as stabilizers. The processing method was optimized to obtain a stable nanosuspension with particle size < 300 nm. The optimized ABZ NS was coated on microcrystalline cellulose (MCC) to form the nano-coated granules (NCG) and filled in EUDRACAP® for colon targeted delivery. The ABZ NS and NCG achieved ∼ 60 % and ∼55 % drug release, respectively, in presence of bile salt at colonic pH. Half-maximal inhibitory concentration (IC50) of ABZ NS was found to be 1.18 ± 0.081 µM and 3.59 ± 0.080 µM in two colorectal cancer cell lines: HCT 116 and HT-29, respectively. In addition, In vitro 3D tumor assay revealed that ABZ NS has superior tumor growth inhibition activity compared to the control and pure ABZ. The preparation of ABZ NCG in EUDRACAP® could be a promising approach to achieve colon targeted delivery and to repurpose ABZ for the treatment of colorectal cancer.

Nano-titania and carbon nanotube-filled rubber seed oil as machining fluids

Machinists face persistent challenges in managing heat dissipation during cutting operations. To address this issue in an environmentally conscious manner, there is a need for nanofluids crafted from sustainable, eco-friendly materials. This study delves into developing nanocomposites (NCs) of nano-titania (nTiO2) derived from Terminalia catappa leaves and carbon nanotubes (CNTs) in varying compositions (nTiO2/CNTs: 90/10, 70/30, and 50/50 wt%). These NCs underwent comprehensive characterization using techniques such as BET, HRSEM/EDX, HRTEM, XRD, and FTIR. The aim was to evaluate their stability as potential fillers in rubber seed oils (RSOs) for machining operations. Furthermore, the homogenous NC samples in RSO revealed distinct polycentric rings, indicating the dispersion of nTiO2 in CNTs, forming Ti–O–C and Ti–O–Ti networks. XRD analysis identified anatase diffraction peaks, though the CNT peaks were less distinct due to overlap with TiO2 peaks. This successful fusion addresses challenges related to individual fillers, ensuring stable nanosuspension formulation. The TiO2/CNTs (50/50 wt%) NC emerged as particularly effective in dissipating heat from machining interfaces. The study highlights the nanomaterials' high thermal stability, complementing the abundant unsaturated fatty acids in RSOs to create advanced nanofluids for improved machining. The substantial pore volume and stable nanosuspension formation observed are attributed to the large surface area aiding heat removal. Ultimately, the reinforced RSO with nTiO2/CNTs shows promising potential for safe and efficient machining applications.

Preparation and Comprehensive Evaluation of the Efficacy and Safety of Chlorantraniliprole Nanosuspension.

Chlorantraniliprole is a broad-spectrum insecticide that has been widely used to control pests in rice fields. Limited by its low solubility in both water and organic solvents, the development of highly efficient and environmentally friendly chlorantraniliprole formulations remains challenging. In this study, a low-cost and scalable wet media milling technique was successfully employed to prepare a chlorantraniliprole nanosuspension. The average particle size of the extremely stable nanosuspension was 56 nm. Compared to a commercial suspension concentrate (SC), the nanosuspension exhibited superior dispersibility, as well as superior foliar wetting and retention performances, which further enhanced its bioavailability against Cnaphalocrocis medinalis. The nanosuspension dosage could be reduced by about 40% while maintaining a comparable efficacy to that of the SC. In addition, the chlorantraniliprole nanosuspension showed lower residual properties, a lower toxicity to non-target zebrafish, and a smaller effect on rice quality, which is conducive to improving food safety and the ecological safety of pesticide formulations. In this work, a novel pesticide-reduction strategy is proposed, and theoretical and data-based support is provided for the efficient and safe application of nanopesticides.

Rebamipide nanocrystal with improved physicomechanical properties and its assessment through bio-mimicking 3D intestinal permeability model.

This study investigated the formulation and characterization of rebamipide nanocrystals (REB-NCs) to enhance the solubility and permeability of rebamipide, an anti-ulcer medication known for its low aqueous solubility and permeability, classified as BCS class IV. Employing high-pressure homogenization and wet milling techniques, we successfully achieved nanonization of rebamipide, resulting in stable nanosuspensions that were subsequently freeze-dried to produce REB-NCs with an average particle size of 223 nm. Comprehensive characterization techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) confirmed the crystalline nature of the nanocrystals and their compatibility with the selected excipients. The saturation solubility study revealed a remarkable three-fold enhancement in PBS pH 7.4 compared to rebamipide API, indicating the effectiveness of the nanocrystal formulation in improving drug solubility. Furthermore, 3D in-vitro permeability assessments conducted on Caco-2 cell monolayers demonstrated an noticeable increase in the permeability of REB-NCs relative to the pure active pharmaceutical ingredient (API), highlighting the promise of this formulation to enhance drug absorption. The dissolution profile of the nanocrystal tablets exhibited immediate release characteristics, significantly outperforming conventional formulations in terms of the dissolution rate. This research underscores the potential of nanomilling as a scalable, environment-friendly, and less toxic approach to significantly enhance the bioavailability of rebamipide. By addressing the challenges associated with the solubility and permeability of poorly water-soluble drugs, our outcome offers insightful information into developing efficient nanomedicine strategies for enhancing therapeutic outcomes.

Utilizing Molecular Simulations to Examine Nanosuspension Stability.

Drug nanosuspensions offer a promising approach to improve bioavailability for poorly soluble drug candidates. Such formulations often necessitate the inclusion of an excipient to stabilize the drug nanoparticles. However, the rationale for the choice of the correct excipient for a given drug candidate remains unclear. To gain molecular insight into formulation design, this work first utilizes a molecular dynamics simulation to computationally investigate drug-excipient interactions for a number of combinations that have been previously studied experimentally. We find that hydrophobic interactions drive excipient adsorption to drug nanoparticles and that the fraction of polar surface area serves as a predictor for experimental measurements of nanosuspension stability. To test these ideas prospectively, we applied our model to an uncharacterized drug compound, GDC-0810. Our simulations predicted that a salt form of GDC-0810 would lead to more stable nanosuspensions than the neutral form; therefore, we tested the stability of salt GDC-0810 nanosuspensions and found that the salt form readily formed nanosuspensions even without the excipient. To avoid computationally expensive simulations in the future, we extended our model by showing that simple, two-dimensional properties of single drug molecules can be used to rationalize nanosuspension designs without simulations. In all, our work demonstrates how computational tools can provide molecular insight into drug-excipient interactions and aid in rational formulation design.

Preparation of Dispersed Copper(II) Oxide Nanosuspensions as Precursor for Femtosecond Reductive Laser Sintering by High-Energy Ball Milling.

This contribution demonstrates and discusses the preparation of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS). Since the presence of agglomerates interferes with the various RLS sub-processes, fine dispersion is required, and oversized particles must be identified by a measurement methodology. Aside from the established method of scanning electron microscopy for imaging individual dried particles, this work applies the holistic and statistically more significant laser diffraction in combination with dynamic image analysis in wet dispersion. In addition to direct ultrasonic homogenization, high-energy ball milling is introduced for RLS, to produce stable nanosuspensions with a high fine fraction, and, above all, the absence of oversize particles. Whereas ultrasonic dispersion stagnates at particle sizes between 500 nm and 20 μm, even after 8 h, milled suspension contains a high proportion of finest particles with diameters below 100 nm, no agglomerates larger than 1 μm and a trimodal particle size distribution with the median at 50 nm already, after 100 min of milling. The precursor layers produced by doctor blade coating are examined for their quality by laser scanning microscopy. The surface roughness of such a dry film can be reduced from 1.26 μm to 88 nm by milling. Finally, the novel precursor is used for femtosecond RLS, to produce homogeneous, high-quality copper layers with a sheet resistance of 0.28Ω/sq and a copper mass concentration of 94.2%.

Investigation of the Interaction between Mechanosynthesized ZnS Nanoparticles and Albumin Using Fluorescence Spectroscopy.

In this paper, ZnS nanoparticles were bioconjugated with bovine serum albumin and prepared in a form of nanosuspension using a wet circulation grinding. The stable nanosuspension with monomodal particle size distribution (d50 = 137 nm) and negative zeta potential (-18.3 mV) was obtained. The sorption kinetics and isotherm were determined. Interactions between ZnS and albumin were studied using the fluorescence techniques. The quenching mechanism, describing both static and dynamic interactions, was investigated. Various parameters were calculated, including the quenching rate constant, binding constant, stoichiometry of the binding process, and accessibility of fluorophore to the quencher. It has been found that tryptophan, in comparison to tyrosine, can be closer to the binding site established by analyzing the synchronous fluorescence spectra. The cellular mechanism in multiple myeloma cells treated with nanosuspension was evaluated by fluorescence assays for quantification of apoptosis, assessment of mitochondrial membrane potential and evaluation of cell cycle changes. The preliminary results confirm that the nontoxic nature of ZnS nanoparticles is potentially applicable in drug delivery systems. Additionally, slight changes in the secondary structure of albumin, accompanied by a decrease in α-helix content, were investigated using the FTIR method after analyzing the deconvoluted Amide I band spectra of ZnS nanoparticles conjugated with albumin. Thermogravimetric analysis and long-term stability studies were also performed to obtain a complete picture about the studied system.

Production of highly concentrated commodity thermoplastic NP suspensions with 3D printed confined impinging jet mixers and efficient downstream operations

A wide application of polymeric nanoparticles (NP) is challenging due to the low productivity of their production methods. While flash nanoprecipitation (FNP) with confined impinging jet mixers is a fast and easily scalable approach, its vast application is still limited due to the scarce availability of mixers and the production of dilute suspensions. This research proposes a modified additive manufacturing route to efficiently and flexibly manufacture polypropylene micromixers. The effects of process and formulation parameters on the size of poly(methyl methacrylate) particles were found to be consistent with literature, thus proving the robustness and suitability of the system to run a FNP process with commodity thermoplastics. By tuning the downstream operations, stable nanosuspensions with 300 mg mL −1 polymer concentration and particle size in the range of 300 nm were produced. This approach for high-volume production of concentrated NP suspensions opens new application scenarios of nanoparticulate materials in commodity sectors such as textiles and coatings. • Robust, scalable, and easily accessible manufacturing of confined impinging jet mixers using modified additive process. • Flash nanoprecipitation with commodity thermoplastics. • Optimized downstream processing for production of concentrated nanoparticle suspensions. • Fully reversible agglomerates upon ultrasonication after storage.

Developing Novel Hydroxypropyl-β-Cyclodextrin-Based Nanosponges as Carriers for Anticancer Hydrophobic Agents: Overcoming Limitations of Host-Guest Complexes in a Comparative Evaluation.

This study aimed to design and fabricate novel hydroxypropyl-β-cyclodextrin-based hypercrosslinked polymers, called nanosponges, as carriers for anticancer hydrophobic agents and compare them with host–guest complexes of hydroxypropyl-β-cyclodextrin, a remarkable solubilizer, to investigate their application in improving the pharmaceutical properties of the flavonoid naringenin, a model hydrophobic nutraceutical with versatile anticancer effects. For this purpose, three new nanosponges, crosslinked with pyromellitic dianhydride, citric acid, and carbonyldiimidazole, were fabricated. The carbonate nanosponge synthesized by carbonyldiimidazole presented the highest naringenin loading capacity (≈19.42%) and exerted significantly higher antiproliferative effects against MCF-7 cancer cells compared to free naringenin. Additionally, this carbonate nanosponge formed a stable nanosuspension, providing several advantages over the naringenin/hydroxypropyl-β-cyclodextrin host–guest complex, including an increase of about 3.62-fold in the loading capacity percentage, sustained released pattern (versus the burst pattern of host–guest complex), and up to an 8.3-fold increase in antiproliferative effects against MCF-7 cancer cells. Both naringenin-loaded carriers were less toxic to L929 murine fibroblast normal cells than MCF-7 cancer cells. These findings suggest that hydroxypropyl-β-cyclodextrin-based carbonate nanosponges could be a good candidate as a drug delivery system with potential applications in cancer treatment.

Formulation, Evaluation, and Optimization of Glimepiride Nanosuspension by Using Antisolvent Evaporation Technique

Recent work aimed to prepare nanosuspension of glimepiride by using antisolvent evaporation followed by sonication technique. As glimepiride belongs to BCS class II, thus it has less solubility and high permeability. Hence to enhance the solubility of glimepiride, it was formulated into nanosuspension. Different polymers were used to prepare stable nanosuspension by taking several trial batches. After getting the results from trial batches, the combination of Pluronic F68 and PEG 400 was selecte

Fabrication of Stable Apigenin Nanosuspension with PEG 400 as Antisolvent for Enhancing the Solubility and Bioavailability.

The purpose of this paper is to prepare a stable apigenin nanosuspension with a drug concentration of 1.11mg/mL through green and efficient antisolvent method. Compared with the traditional preparation process that may use toxic reagents, in this study, a green and effective strategy was applied for the preparation of stable apigenin nanosuspension by using an antisolvent method with PEG 400 as antisolvent to improve the solubility and bioavailability. It was found that the particle size of apigenin nanosuspension was about 280nm, and the solubility and dissolution of the nanosuspension were 33 and 3 times higher than that of the apigenin, respectively. Pharmacokinetic study showed that the Cmax and AUC 0-8h values of the nanosuspension in fasting rats achieved about 6- and 2.5-fold enhancement than that of the apigenin, respectively. Stability test showed that the apigenin nanosuspension could be stored stably for 12months at 25℃. Taken together, the antisolvent method with PEG 400 was proven to be a green and effective method to prepare the stable nanosuspension of poorly soluble drugs.

Bmk9 and Uricase Nanoparticle Complex for the Treatment of Gouty Arthritis and Uric Acid Nephropathy.

Uric acid is the final product of purine metabolism, and excessive serum uric acid can cause gouty arthritis and uric acid nephropathy. Therefore, lowering the uric acid level and alleviating inflammation in the body are the key points to treating these diseases. A stable nanosuspension of peptide BmK9 was prepared by the precipitation-ultrasonication method. By combining uricase on the surface of a positively charged carrier, a complex consisting of neutral rod-shaped BmK9 and uricase nanoparticles (Nplex) was formed to achieve the delivery of BmK9 and uricase, respectively. The formulation of Nplex has a diameter of 180 nm and drug loading up to 200%, which releases BmK9 and uricase slowly and steadily in drug release tests in vitro. There was significantly improved pharmacokinetic behavior of the two drugs because Nplex prolonged the half-life and increased tissue accumulation. Histological assessments showed that the dual drug Nplex can reduce the inflammation response in acute gouty arthritis and chronic uric acid nephropathy in vivo. In the macrophage system, there was lower toxicity and increased beneficial effect on inflammation with Nplex than free BmK9 or uricase. Collectively, this novel formulation provides a dual drug delivery system that can treat gouty arthritis and uric acid nephropathy.

Preparation of stable nanosuspensions from Asplenium scolopendrium leaves via rapid expansion of supercritical solution into aqueous solutions (RESSAS)

The present study intended to stabilize the nanosuspension of powerful antioxidants such as genistein, quercetin, as well as caffeic acid from the leaves related to Asplenium scolopendrium by utilizing the RESSAS process. These compounds offer low efficacy and bioavailability since they are barely soluble in aqueous media. Thus, producing stable nanosuspensions can resolve this problem by reducing the size of the particle. In addition, central composite design (CCD) was used for analyzing the impact of oven temperature, pressure, CO2 flow rate, and modifier volume on the antioxidant activity index (AAI) in the outcome of RESSAS process. Further, DLS, FE-SEM, and LC-MS techniques were implemented for evaluating the nanosuspension features. Based on the results, the behavior of the particles after forming particle was emphasized, which indicated that the RESSAS process results in diminished agglomeration of the particle and enhanced AAI for the extract. Thus, the bioavailability of the products related to herbal medicinal can be dramatically increased in biological media.

Polypeptide and glycosaminoglycan polysaccharide as stabilizing polymers in nanocrystals for a safe ocular hypotensive effect

Improved ocular delivery of a poorly soluble anti-glaucoma drug, acetazolamide (ACZ), in a stable nanosuspension (NS) was the main target of the study. The anionic polypeptide, poly-γ-glutamic acid (PG) and the glycosaminoglycan, hyaluronic acid, were used to stabilize ACZ-NS prepared using the antisolvent precipitation (AS-PT) coupled with sonication technique. To endue in site biocompatibility with high tolerability, soya lecithin (SL) phospholipid has been also combined with polyvinyl alcohol (PVA). NS with uniform PS in the range 100–300 nm, high ζ > ±20 mV, and enhanced saturation solubility were produced. Targeting solvent removal with control on future particle growth, post-production processing of NS was done using spray drying. The carriers' composition and amount relative to ACZ-NS were optimized to allow for the production of a redispersible dry crystalline powder. Particles crystallinity was confirmed using X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) in liquid and spray dried NS. The modified Draize test proved the safety and tolerability following application to rabbit eyes accompanying an efficient ocular hypotensive activity using a steroid glaucoma model.

Design, Synthesis, and Preclinical Evaluation of 3-Methyl-6-(5-thiophenyl)-1,3-dihydro-imidazo[4,5-b]pyridin-2-ones as Selective GluN2B Negative Allosteric Modulators for the Treatment of Mood Disorders

Selective inhibitors of the GluN2B subunit of N-methyl-d-aspartate receptors in the ionotropic glutamate receptor superfamily have been targeted for the treatment of mood disorders. We sought to identify structurally novel, brain penetrant, GluN2B-selective inhibitors suitable for evaluation in a clinical setting in patients with major depressive disorder. We identified a new class of negative allosteric modulators of GluN2B that contain a 1,3-dihydro-imidazo[4,5-b]pyridin-2-one core. This series of compounds had poor solubility properties and poor permeability, which was addressed utilizing two approaches. First, a series of structural modifications was conducted which included replacing hydrogen bond donor groups. Second, enabling formulation development was undertaken in which a stable nanosuspension was identified for lead compound 12. Compound 12 was found to have robust target engagement in rat with an ED70 of 1.4 mg/kg. The nanosuspension enabled sufficient margins in preclinical toleration studies to nominate 12 for progression into advanced good laboratory practice studies.

Preparation of potent antioxidant nanosuspensions from olive leaves by Rapid expansion of supercritical solution into aqueous solutions (RESSAS)

The aim of this work is to prepare and stabilize potent antioxidant nanoparticles such as α-tocopherol and β-amyrin from Olea europaea leaves using the RESSAS process. These compounds have a low bioavailability and efficacy, as they are barely soluble in aqueous media. For this reason, providing stable nanosuspensions out of them could solve the problem using an increased solubility. The effects of pressure, oven temperature, modifier volume and CO2 flow rate on the antioxidant activity index (AAI) of the RESSAS process outcome were analyzed by applying central composite design (CCD). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was conducted in aqueous solution to the determined AAI. In addition, the specifications of nanosuspension were studied using a dynamic light scattering (DLS) technique. The results emphasize the post-treatment of the particles, after particle formation and show that the RESSAS process leads to the minimization of particle agglomeration and improvement of AAI for the extracted nanosuspension.

Screening of stabilizing agents to optimize flurbiprofen nanosuspensions using experimental design

Although flurbiprofen (FB), as one of non-steroidal anti-inflammatory drugs, has various pharmacological applications, it shows low dermal bioavailability due to its low water solubility. To overcome this solubility problem, FB nanosuspensions were developed and the effects of stabilizers were investigated with regard to critical quality attributes. While PVP K30 and HPMC 3 cps were used as non-ionic polymeric stabilizer, Tween 80 and Plantacare 2000 (PL) were used as non-ionic surfactants. The influence of these types of stabilizers and their different ratios were tested. The selected formulations according to results of experimental design were also characterized by SEM, FTIR, XRPD, DSC, and the stability studies were performed. According to results of characterization studies, PL was selected as the appropriate stabilizer. The determined nanosuspension stabilized with PL had the nanosized, spherical, and homogenous dispersed particles. There is no polymorphic change on the crystalline state of FB while producing nanosuspension stabilized with PL. It also retained its stability compared with PVP stabilized nanosuspensions for one month. It was concluded that the design of experimental approach is a useful tool to determine the effect of stabilizer on quality attributes of nanosuspensions and to select the optimum type and ratio of stabilizer for obtaining more stable nanosuspensions.

Preparation of Nanocrystals for Insoluble Drugs by Top-Down Nanotechnology with Improved Solubility and Bioavailability.

Midazolam is a rapidly effective benzodiazepine drug that is widely used as a sedative worldwide. Due to its poor solubility in a neutral aqueous solution, the clinical use of midazolam is significantly limited. As one of the most promising formulations for poorly water-soluble drugs, nanocrystals have drawn worldwide attention. We prepared a stable nanosuspension system that causes little muscle irritation. The particle size of the midazolam nanocrystals (MDZ/NCs) was 286.6 ± 2.19 nm, and the crystalline state of midazolam did not change in the size reduction process. The dissolution velocity of midazolam was accelerated by the nanocrystals. The pharmacokinetics study showed that the AUC0–t of the MDZ/NCs was 2.72-fold (p < 0.05) higher than that of the midazolam solution (MDZ/S), demonstrating that the bioavailability of the MDZ/NC injection was greater than that of MDZ/S. When midazolam was given immediately after the onset of convulsions, the ED50 for MDZ/NCs was significantly more potent than that for MDZ/S and DZP/S. The MDZ/NCs significantly reduced the malondialdehyde content in the hippocampus of the seizures model rats and significantly increased the glutathione and superoxide dismutase levels. These results suggest that nanocrystals significantly influenced the dissolution behavior, pharmacokinetic properties, anticonvulsant effects, and neuroprotective effects of midazolam and ultimately enhanced their efficacy in vitro and in vivo.

Study on the stabilization mechanisms of wet-milled cepharanthine nanosuspensions using systematical characterization

Objectives: Stability issues are inevitable problems that are encountered in nanosuspension (NS) technology developments and in the industrial application of pharmaceuticals. This study aims to assess the stability of wet-milled cepharanthine NSs and elucidate the stabilization mechanisms of different stabilizers.Methods: The aggregation state was examined via scanning electron microscopy, laser diffraction, and rheometry. The zeta potential, stabilizer adsorption, surface tension, and drug-stabilizer interactions were employed to elucidate the stabilization mechanisms.Results: The results suggest that croscarmellose sodium (CCS), D-α-tocopherol polyethylene glycol 1000 succinate (TPGS), or polyvinyl pyrrolidone VA64 (PVP VA64) alone was able to prevent nanoparticle aggregation for at least 30 days. Attempts to evaluate the stability mechanisms of different stabilization systems revealed that CCS improved the steric-kinetic stabilization of the NSs, attributed to its high viscosity, swelling capacity, and physical barrier effects. In contrast, the excellent physical stability of TPGS systems was mainly due to the reduced surface tension and higher crystallinity. PVP VA64 can adsorb onto the surfaces of nanoparticles and stabilize the NS via steric forces.Conclusion: This study demonstrated the complex effects of CCS, TPGS, and PVP VA64 on cepharanthine NS stability and presented an approach for the rational design of stable NSs.

Easy preparation method of stable copper‐based nanoparticle suspensions in lubricant engine oil

AbstractNanolubricants, thanks to their ability to reduce friction and wear, are increasingly studied in the transport and automotive sectors. These systems are generally produced with a two‐step procedure by dispersing nanoparticles into base oils. Very recently, one‐step methods have received increasing attention for the production of highly stable nanosuspensions at lower cost. Degradation‐decomposition of the base oil can however occur during the synthesis affecting the final performances. In this work, copper‐based nanolubricants were produced using a new procedure that preserves the base oil from the degradation induced by the synthesis and allows producing highly stable nanolubricant. The produced fluid showed a monodisperse distribution of nanometric particles and a good stability up to at least 60 days from its production. The as‐produced nanolubricants showed notable performance reducing the friction coefficient even up to 32.7% for Cu concentration of 0.01 vol% at 80°C.