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Stability improvement of algal-alginate beads by zeolite molecular sieves 13X

Emami Moghaddam SA, Harun R, Mokhtar MN, Zakaria R

Int J Biol Macromol, 2019 Jul 01;132:592-599.
PMID: 30922914 DOI: 10.1016/j.ijbiomac.2019.03.191

This research aimed to improve the stability of Chlorella-Alginate Beads (CABs) by zeolite molecular sieves 13X. Dissolution time of synthesized Zeolite-Algal-Alginate Beads (ZABs) in a chelating agent revealed a significant improvement on the beads stability (78.5 ± 0.5 min) compared to the control beads (51.5 ± 0.5 min) under the optimum conditions of zeolite/alginate (1.5:1), pH 5 and 2% of beads. Monitoring cell growth during 5 days of incubation showed good biocompatibility of zeolite 13X. Scanning electron microscopy (SEM) indicated rough surface and spherical shapes of ZABs. Energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR) of ZABs confirmed the presence of zeolite 13X within the matrix. The zeta potential value of ZABs indicated that the beads were relatively stable. The findings of this research showed that zeolite molecular sieves 13X have the potential to improve the stability of algal-alginate beads compared to common beads.

Matched MeSH terms: Solubility
Fulltext Curcumin Nanoformulations for Colorectal Cancer: A Review

Wong KE, Ngai SC, Chan KG, Lee LH, Goh BH, Chuah LH

Front Pharmacol, 2019;10:152.
PMID: 30890933 DOI: 10.3389/fphar.2019.00152

Colorectal cancer (CRC) is the third most prevalent form of cancer, after lung cancer and breast cancer, with the second highest death incidence. Over the years, natural compounds have been explored as an alternative to conventional cancer therapies such as surgery, radiotherapy, and chemotherapy. Curcumin, an active constituent of turmeric has been associated with various health benefits. It has gained much attention as an anticancer agent due to its ability to regulate multiple cell signaling pathways, including NF-κB, STAT3, activated protein-1 (AP-1), epidermal growth response-1 (Egr-1), and p53, which are crucial in cancer development and progression. Nevertheless, the clinical application of curcumin is greatly restricted because of its low water solubility, poor oral absorption, and rapid metabolism. These issues have led to the development of curcumin nanoformulations to overcome the limitations of the compound. Nanotechnology-based delivery systems have been widely used in improving the delivery of poorly-water soluble drugs. Besides, these systems also come with the added benefits of possible cellular targeting and improvement in cellular uptake. An ideal improved formulation should display a greater anticancer activity compared to free curcumin, and at the same time be non-toxic to the normal cells. In this review, we focus on the design and development of various nanoformulations to deliver curcumin for use in CRC such as liposomes, micelles, polymer nanoparticles, nanogels, cyclodextrin complexes, solid lipid nanoparticles (SLN), phytosomes, and gold nanoparticles. We also discuss the current pre-clinical and clinical evidences of curcumin nanoformulations in CRC therapy, analyse the research gap, and address the future direction of this research area.

Matched MeSH terms: Solubility
Fulltext Characterisation and Evaluation of Trimesic Acid Derivatives as Disulphide Cross-Linked Polymers for Potential Colon Targeted Drug Delivery

Mat Yusuf SNA, Ng YM, Ayub AD, Ngalim SH, Lim V

Polymers (Basel), 2017 Jul 27;9(8).
PMID: 30970988 DOI: 10.3390/polym9080311

Discovery and use of biocompatible polymers offers great promise in the pharmaceutical field, particularly in drug delivery systems. Disulphide bonds, which commonly occur in peptides and proteins and have been used as drug-glutathione conjugates, are reductively cleaved in the colon. The intrinsic stability of a disulphide relative to thiol groups is determined by the redox potential of the environment. The objective of this study was to synthesise a trimesic acid-based disulphide cross-linked polymer that could potentially be used for targeted delivery to the colon. The monomer was synthesised by an amide coupling reaction between trimesic acid and (triphenylmethyl) thioethylamine using a two-step synthesis method. The s-trityl group was removed using a cocktail of trifluoroacetic acid and triethylsilane to expose the thiols in preparation for further polymerisation. The resulting polymers (P10, P15, P21, P25, and P51, generated using different molar ratios) were reduced after 1.5 h of reduction time. Scanning electron microscopy images of the polymers showed spherical, loose, or tight patterns depending on the molar ratio of polymerisation. These polymers also exhibited efficient dissolution under various gastrointestinal conditions. Of the five polymers tested, P10 and P15 appeared to be promising drug delivery vehicles for poorly soluble drugs, due to the hydrophobic nature of the polymers.

Matched MeSH terms: Solubility
In Vitro Drug Dissolution/Permeation Testing of Nanocarriers for Skin Application: a Comprehensive Review

Sheshala R, Anuar NK, Abu Samah NH, Wong TW

AAPS PharmSciTech, 2019 Apr 15;20(5):164.
PMID: 30993407 DOI: 10.1208/s12249-019-1362-7

This review highlights in vitro drug dissolution/permeation methods available for topical and transdermal nanocarriers that have been designed to modulate the propensity of drug release, drug penetration into skin, and permeation into systemic circulation. Presently, a few of USFDA-approved in vitro dissolution/permeation methods are available for skin product testing with no specific application to nanocarriers. Researchers are largely utilizing the in-house dissolution/permeation testing methods of nanocarriers. These drug release and permeation methods are pending to be standardized. Their biorelevance with reference to in vivo plasma concentration-time profiles requires further exploration to enable translation of in vitro data for in vivo or clinical performance prediction.

Matched MeSH terms: Solubility
Solubility enhancement effect at absorption site on bioavailability of ritonavir using liquisolid technique

Bonthagarala B, Dasari V, Kotra V

Ther Deliv, 2019 May 01;10(5):295-310.
PMID: 31094300 DOI: 10.4155/tde-2019-0020

Aim: The present study revolved around determining the effect of increase in the solubility of these drugs at the absorption site using ritonavir as a drug model. Materials & methods: Ritonavir per-oral tablets were prepared using versatile and nonionic surfactants having high solubilization rate, which were further marked with high rate of dissolution. The high rate of dissolution formula applied to the solid state characterization by means of transition electron microscopy, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction and infrared spectroscopy. Results & conclusion: The drug bioavailability was seen to increase expressively by administration of liquisolid tablets as compared with conventional tablets.

Matched MeSH terms: Solubility
Mechanical and antibacterial properties of paper coated with chitosan

Sarani Zakaria, Chin HC, Wan Haslinda Wan Ahmad, Hatika Kaco, Soon Wei Chook, Chi HC

Sains Malaysiana, 2015;44:905-911.

Recent developments have found the viability of chitosan as a new alternative additive in the pulp and paper technology.
This study was carried out to investigate the effect of chitosan as a paper coating which were prepared by dissolution in
acetic acid solution. The mechanical properties of coated paper were improved significantly compared with non-coated
paper. The FT-IR spectra showed peak evolution at 1558 cm-1 for coated paper due to the existence of amine group. Since
FT-IR spectra for the coated paper was almost identical to the chitosan spectrum, it is assumed that there is an obvious
physical interaction rather than the chemical interaction. The SEM micrographs showed that some of the chitosan has
occupied the pores and some of them adhered only on the surface. This may be due to the chemical similarities between
cellulose and chitosan which enhanced the strength of fiber matrixes via hydrogen bonding. The antibacterial property
of coated paper showed that chitosan in dried form has no significant effect but effective when applied as wet solution.

Matched MeSH terms: Solubility
Physico-mechanical properties of kenaf pulp cellulose membrane cross-linked with glyoxal

Anis Syuhada Mohd Saidi, Chin HC, Sharifah Nabihah Syed Jaafar, Farah Nadia Mohammad Padzil, Sarani Zakaria

Sains Malaysiana, 2016;45:263-270.

Cellulose was extracted from kenaf core pulp (KCP) by a series of bleaching processes (D) and alkali treatment (E) in the sequence of (DEED) and pretreated with acid hydrolysis in room temperature for 6 hours. The pretreated and non-treated cellulose were dissolved in lithium hydroxide/urea (LiOH/urea) and subsequently used to produce cellulose membrane cross linked with various percentages of glyoxal from 2.5 to 20%. The effects of acid hydrolysis pretreatment on solubility, crystallinity and morphology were investigated. The acid hydrolysis pretreatment leads to higher solubility of the cellulose solution. The formation of cellulose II and crystallinity index of the cellulose membrane were examined by X-ray diffraction (XRD). Cellulose membrane without acid hydrolysis pretreatment cross linked with higher percentage of glyoxal has higher tensile strength compared with the treated cellulose.

Matched MeSH terms: Solubility
A comparative study between tilapia (oreochromis niloticus) by-product and tilapia protein hydrolysate on angiotensin I-converting enzyme (ace) inhibition activities and functional properties

Siti Mazlina Mustapa Kamal, Khairul Faezah Md. Yunos, Norhafizah Abdullah

Sains Malaysiana, 2018;47:309-318.

Tilapia is a popular freshwater fish and among the important cultured fish grown worldwide. In this study, fish protein
hydrolysate was produced from tilapia (Oreochromis niloticus) by-product (TB) and tilapia muscle (TM) through enzymatic
hydrolysis using alcalase. The TB and TM protein hydrolysates were evaluated for its characteristics in terms of angiotensin
I-converting enzyme (ACE) inhibition activity, peptide size distribution, and functional properties. Hydrolysis for 1 h for
TB and TM successfully produced low molecular weight peptides (<14.2kDa) with the highest ACE inhibitory activities.
The findings also demonstrated that both samples have high nitrogen solubility (>80% at pH2-9) and good emulsifying,
water and oil holding capacities. The study indicated that tilapia protein hydrolysates have the potential to be used as
functional food products.

Matched MeSH terms: Solubility
Fulltext Phase behavior and fluid interactions of a CO2-Light oil system at high pressures and temperatures

Rezk MG, Foroozesh J

Heliyon, 2019 Jul;5(7):e02057.
PMID: 31384679 DOI: 10.1016/j.heliyon.2019.e02057

This paper investigates the phase behavior and mutual interactions between a light crude oil and CO2 at high pressures and high temperatures (HPHT). To do so, we have measured PVT properties of the CO2-oil system at HPHT using a PVT setup. We have also tried to present a detailed methodology for measuring PVT properties of CO2-oil systems and highlight the difficulties such as oil vaporization by CO2 during the experiments. A crude oil sample, collected from a Malaysian oil field, was used here. Our experiments indicated that, CO2 solubility in the oil increased at higher pressures when measured at a fixed temperature. Our experiments also showed that increasing the test temperature would reduce CO2 solubility in the oil, while its effect is more significant at higher pressures. The swelling factor (SF) measurements showed an increasing trend with pressure up to a certain value so-called extraction pressure, at which, the SF started to be reduced even became less than one. The measurements of oil viscosity indicated that CO2 dissolution in the oil sample could reduce the mixture viscosity up to 61%. The interfacial tensions between CO2 and the crude oil at different pressures were also measured while the results were used to estimate the minimum miscibility pressure (MMP) and the first contact miscibility (FCM) pressure. The IFT measurements at various pressures displayed a reduction trend as a result of more CO2 dissolution in the oil but with two different slopes. That is, at lower pressure values, the measured IFTs were sharply reduced with pressure, while the reduction rate of the IFT became less when pressures exceeded the extraction pressure. This study helps with determining the optimum pressure and temperature conditions of CO2-oil systems to have a minimum IFT, a maximum CO2 solubility and SF, and a minimum oil viscosity that are favorable for CO2-enhanced oil recovery projects. Additionally, the methodology presented here gives guidelines on how to design PVT experiments of CO2-oil systems for petroleum and chemical engineering applications.

Matched MeSH terms: Solubility
An Application of pET SUMO Protein Expression System in Escherichia coli: Cloning, Expression, Purification, and Characterisation of Native Kras4BG12V Oncoprotein

Tan MS, Teh YH, Ho KL, Stanslas J

Protein J, 2020 02;39(1):54-61.
PMID: 31620959 DOI: 10.1007/s10930-019-09872-1

Being an important regulator of cell growth and survival, a point mutation at glycine-12 residue of Kras4B to valine (V), renders Kras4BG12V oncogenic. Kras4B recombinant protein is used as a bait to fish its potential ligands in the attempt of drugging this oncoprotein and to validate its pharmacologically relevant ligand in protein-ligand interaction studies. Nevertheless, synthesis of Kras4B recombinant protein is challenging as it was reported being susceptible to aggregation into inclusion bodies in the bacterial host, resulting in a poor yield of recombinant protein. Here, we describe a novel method to produce native Kras4BG12V protein by using pET SUMO protein expression system as a solution to the formation of inclusion bodies. Kras4BG12V oncogene was cloned into pET SUMO vector, followed by a 12 h chemically induced protein expression in Escherichia coli at 20 °C. Native Kras4BG12V protein was produced in a series of protein purification steps involving immobilised nickel ion-affinity column chromatography, SUMO fusion protein and polyhistidine tag removal, and size exclusion column chromatography. The identity of the purified Kras4BG12V protein was validated by immunoblot analysis. The purified protein exhibited self-dimerising, indicating that the purified protein structurally resembles Kras4B. Its physical interaction with 4,6-dichloro-2-methyl-3-aminoethyl-indole (DCAI), a known binder of Kras4B, confirms the identity of the purified protein as Kras4BG12V. The native Kras4BG12V protein was successfully purified in a substantial amount by using the pET SUMO protein expression system.

Matched MeSH terms: Solubility
Lapatinib nano-delivery systems: a promising future for breast cancer treatment

Bonde GV, Yadav SK, Chauhan S, Mittal P, Ajmal G, Thokala S, et al.

Expert Opin Drug Deliv, 2018 05;15(5):495-507.
PMID: 29521126 DOI: 10.1080/17425247.2018.1449832

INTRODUCTION: Breast cancer stands the second prominent cause of death among women. For its efficient treatment, Lapatinib (LAPA) was developed as a selective tyrosine kinase inhibitor of receptors, overexpressed by breast cancer cells. Various explored delivery strategies for LAPA indicated its controlled release with enhanced aqueous solubility, improved bioavailability, decreased plasma protein binding, reduced dose and toxicity to the other organs with maximized clinical efficacy, compared to its marketed tablet formulation.
AREAS COVERED: This comprehensive review deals with the survey, performed through different electronic databases, regarding various challenges and their solutions attained by fabricating delivery systems like nanoparticles, micelle, nanocapsules, nanochannels, and liposomes. It also covers the synthesis of novel LAPA-conjugates for diagnostic purpose.
EXPERT OPINION: Unfortunately, clinical use of LAPA is restricted because of its extensive albumin binding capacity, poor oral bioavailability, and poor aqueous solubility. LAPA is marketed as the oral tablet only. Therefore, it becomes imperative to formulate alternate efficient multiparticulate or nano-delivery systems for administration through non-oral routes, for active/passive targeting, and to scale-up by pharmaceutical scientists followed by their clinical trials by clinical experts. LAPA combinations with capecitabine and letrozole should also be tried for breast cancer treatment.

Matched MeSH terms: Solubility
Fulltext Supersaturation Potential of Amorphous Active Pharmaceutical Ingredients after Long-Term Storage

Edueng K, Mahlin D, Gråsjö J, Nylander O, Thakrani M, Bergström CAS

Molecules, 2019 Jul 27;24(15).
PMID: 31357587 DOI: 10.3390/molecules24152731

This study explores the effect of physical aging and/or crystallization on the supersaturation potential and crystallization kinetics of amorphous active pharmaceutical ingredients (APIs). Spray-dried, fully amorphous indapamide, metolazone, glibenclamide, hydrocortisone, hydrochlorothiazide, ketoconazole, and sulfathiazole were used as model APIs. The parameters used to assess the supersaturation potential and crystallization kinetics were the maximum supersaturation concentration (Cmax,app), the area under the curve (AUC), and the crystallization rate constant (k). These were compared for freshly spray-dried and aged/crystallized samples. Aged samples were stored at 75% relative humidity for 168 days (6 months) or until they were completely crystallized, whichever came first. The solid-state changes were monitored with differential scanning calorimetry, Raman spectroscopy, and powder X-ray diffraction. Supersaturation potential and crystallization kinetics were investigated using a tenfold supersaturation ratio compared to the thermodynamic solubility using the µDISS Profiler. The physically aged indapamide and metolazone and the minimally crystallized glibenclamide and hydrocortisone did not show significant differences in their Cmax,app and AUC when compared to the freshly spray-dried samples. Ketoconazole, with a crystalline content of 23%, reduced its Cmax,app and AUC by 50%, with Cmax,app being the same as the crystalline solubility. The AUC of aged metolazone, one of the two compounds that remained completely amorphous after storage, significantly improved as the crystallization kinetics significantly decreased. Glibenclamide improved the most in its supersaturation potential from amorphization. The study also revealed that, besides solid-state crystallization during storage, crystallization during dissolution and its corresponding pathway may significantly compromise the supersaturation potential of fully amorphous APIs.

Matched MeSH terms: Solubility
Fulltext Levofloxacin: Insights Into Antibiotic Resistance and Product Quality

Izadi E, Afshan G, Patel RP, Rao VM, Liew KB, Meor Mohd Affandi MMR, et al.

Front Pharmacol, 2019;10:881.
PMID: 31474853 DOI: 10.3389/fphar.2019.00881

Counterfeit and substandard medicines are recognized as one of serious threats to public health. The product quality of antibacterial medicine will compromise patients' recovery and increase the chance of antibacterial resistance. The review aims to provide a summary of low quality levofloxacin issues and the risk factors as well as suggesting the aspects of product quality that need to be regulated strictly. Quality of the active ingredient, levofloxacin, has an important role to contribute to successful therapy. The poor quality of raw material, directly and indirectly, causes treatment failure as the presence of insufficient dose, mislabeled content, and poor dissolution characteristics can lead to lower bioavailability. Identifying and reporting these factors can potentially help in improving the quality of drug marketed in various developing countries and may also reduce the incidences of treatment failure. Dissolution test is used for testing the dissolution profiles and the rate of drug release from solid formulation such as oral formulations, thus providing information regarding the in vivo performance of a formulation and its bioequivalence. On the other hand, quality-testing procedures are used for comparing the quality of products.

Matched MeSH terms: Solubility
Comparison of Disintegrant-addition Methods on the Compounding of Orodispersible Tablets

Mahesparan VA, Bin Abd Razak FS, Ming LC, Uddin AH, Sarker MZI, Bin LK

Int J Pharm Compd, 2020 3 21;24(2):148-155.
PMID: 32196477

Orodispersible tablets disintegrate rapidly (within 3 minutes) in the oral cavity and release the medicament before swallowing. The mode of disintegrant addition might affect the properties of orodispersible tablets. The objective of this study was to formulate and evaluate orodispersible tablets by studying different modes of disintegration addition with varying concentrations of disintegrants. The wet granulation method was used to produce the orodispersible tablets. Two methods of disintegration addition were compared (i.e., intragranular, extragranular). Three disintegrants (i.e., cornstarch, sodium starch glycolate, crospovidone) were used at three levels (5%, 10%, and 15%) in the study. The formulations were tested for the powder flowability (angle of repose) and characterized physically (hardness, weight, thickness, friability, disintegration time). The mangosteen pericarp extract was used as a model active pharmaceutical ingredient to be incorporated into the optimum formulation. It was observed that the extragranular method produced granules with better flowability compared to that of the intragranular method. Crospovidone was found as the most efficient disintegrant among the three. The optimum formulation selected was one with the highest concentration of crospovidone (15%), which showed the fastest disintegration time. The mode of disintegrant addition into the orodispersible tablets formulation was found to show a marked difference in the disintegration, as well as other physical characteristics of the orodispersible tablets where the extragranular mode of addition showed better property, which caused the orodispersible tablets to disintegrate the fastest.

Matched MeSH terms: Solubility
Fulltext Effects of Slug Size, Soaking, and Injection Schemes on the Performance of Controlled Ions Water Flooding in Carbonates

Moradpour N, Karimova M, Pourafshary P, Zivar D

ACS Omega, 2020 Jul 28;5(29):18155-18167.
PMID: 32743190 DOI: 10.1021/acsomega.0c01766

The results of many previous studies on low salinity/controlled ions water (CIW) flooding suggest that future laboratory and modeling investigations are required to comprehensively understand and interpret the achieved observations. In this work, the aim is co-optimization of the length of the injected slug and soaking time in the CIW flooding process. Furthermore, the possibility of the occurrence of several governing mechanisms is studied. Therefore, the experimental results were utilized to develop a compositional model, using CMG GEM software, in order to obtain the relative permeability curves by history matching. It was concluded that CIW slug injection, concentrated in the potential-determining ion, can increase oil recovery under a multi ion exchange (MIE) mechanism. The wettability of the carbonate rocks was changed from a mixed or oil wet state toward more water wetness. However, there is a CIW slug length, beyond which extending the length does not significantly improve the rock wettability, and consequently, the oil production, which is known as the optimum slug size. This implies that the optimization of the injection process, by minimizing the slug size, can decrease the need for the CIW supply, therefore lowering the process expenditure. Moreover, if the exposure time of the rock and CIW is increased (soaking), a higher level of ion substitution is probable, leading to more oil detachment and production. Rock dissolution/precipitation (leading to a pH change) was found to have a negligible contribution.

Matched MeSH terms: Solubility
Fulltext Optimization of Processing Parameters of Nanoemulsion Containing Aripiprazole Using Response Surface Methodology

Samiun WS, Ashari SE, Salim N, Ahmad S

Int J Nanomedicine, 2020;15:1585-1594.
PMID: 32210553 DOI: 10.2147/IJN.S198914

BACKGROUND: Aripiprazole, which is a quinolinone derivative, has been widely used to treat schizophrenia, major depressive disorder, and bipolar disorder.
PURPOSE: A Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) was used purposely to optimize process parameters conditions for formulating nanoemulsion containing aripiprazole using high emulsification methods.
METHODS: This design is used to investigate the influences of four independent variables (overhead stirring time (A), shear rate (B), shear time (C), and the cycle of high-pressure homogenizer (D)) on the response variable namely, a droplet size (Y) of nanoemulsion containing aripiprazole.
RESULTS: The optimum conditions suggested by the predicted model were: 120 min of overhead stirring time, 15 min of high shear homogenizer time, 4400 rpm of high shear homogenizer rate and 11 cycles of high-pressure homogenizer, giving a desirable droplet size of nanoemulsion containing aripiprazole of 64.52 nm for experimental value and 62.59 nm for predicted value. The analysis of variance (ANOVA) showed the quadratic polynomial fitted the experimental values with F-value (9.53), a low p-value (0.0003) and a non-significant lack of-fit. It proved that the models were adequate to predict the relevance response. The optimized formulation with a viscosity value of 3.72 mPa.s and pH value of 7.4 showed good osmolality value (297 mOsm/kg) and remained stable for three months in three different temperatures (4°C, 25°C, and 45°C).
CONCLUSION: This proven that response surface methodology is an efficient tool to produce desirable droplet size of nanoemulsion containing aripiprazole for parenteral delivery application.

Matched MeSH terms: Solubility
Design of multi-particulate "Dome matrix" with sustained-release melatonin and delayed-release caffeine for jet lag treatment

Razali S, Bose A, Chong PW, Benetti C, Colombo P, Wong TW

Int J Pharm, 2020 Sep 25;587:119618.
PMID: 32673769 DOI: 10.1016/j.ijpharm.2020.119618

Multi-particulate Dome matrix with sustained-release melatonin and delayed-release caffeine was designed to restore jet lag sleep-wake cycle. The polymeric pellets were produced using extrusion-spheronization technique and fluid-bed coated when applicable. The compact and Dome module were produced by compressing pellets with cushioning agent. Dome matrix was assembly of modules with pre-determined compact formulation and drug release characteristics. The physicochemical and in vivo pharmacokinetics of delivery systems were examined. Melatonin loaded alginate/chitosan-less matrix exhibited full drug release within 8 h gastrointestinal transit with low viscosity hydroxypropymethylcellulose as cushioning agent. The cushioning agent reduced burst drug release and omission of alginate-chitosan enabled full drug release. Delayed-release alginate-chitosan caffeine matrix was not attainable through polymer coating due to premature coat detachment. Admixing of cushioning agent high viscosity hydroxypropylmethylcellulose and high viscosity ethylcellulose (9:1 wt ratio) with coat-free caffeine loaded particulates introduced delayed-release response via hydroxypropylmethylcellulose swelled in early dissolution phase and ethylcellulose sustained matrix hydrophobicity at prolonged phase. The caffeine was released substantially in colonic fluid in response to matrix polymers being degraded by rat colonic content. Dome matrix with dual drug release kinetics and modulated pharmacokinetics is produced to introduce melatonin-induced sleep phase then caffeine-stimulated wake phase.

Matched MeSH terms: Solubility
Fulltext Physicochemical Characterization, Molecular Docking, and In Vitro Dissolution of Glimepiride-Captisol Inclusion Complexes

Pal A, Roy S, Kumar A, Mahmood S, Khodapanah N, Thomas S, et al.

ACS Omega, 2020 Aug 18;5(32):19968-19977.
PMID: 32832751 DOI: 10.1021/acsomega.0c01228

This present study investigated the effect of Captisol, a chemically modified cyclodextrin, on the in vitro dissolution of glimepiride. We prepared glimepiride-Captisol complexes of different mass ratios (1:1, 1:2, and 1:3 w/w) by a physical mixing or freeze-drying technique, and found that complexation with Captisol enhanced the water solubility of glimepiride. Molecular docking and dynamic simulation predicted complex formation; at the same time, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, and scanning electron microscope indicated molecular interactions that support complexation. We also found that an inclusion complex was better than a physical mixture in enhancing the complexation of glimepiride with Captisol and enhancing water solubility. Phase solubility study of the glimepiride-Captisol complex showed an AL-type profile, implying the formation of a 1:1 inclusion complex. The study also revealed that pH influenced the stability of the complex because the stability constant of the glimepiride-Captisol complex was higher in distilled water of pH ∼6.0 than in phosphate buffer of pH 7.2.

Matched MeSH terms: Solubility
Fulltext Rheology Impact of Various Hydrophilic-Hydrophobic Balance (HLB) Index Non-Ionic Surfactants on Cyclopentane Hydrates

Foo KS, Bavoh CB, Lal B, Mohd Shariff A

Molecules, 2020 Aug 15;25(16).
PMID: 32824121 DOI: 10.3390/molecules25163725

In this study, series of non-ionic surfactants from Span and Tween are evaluated for their ability to affect the viscosity profile of cyclopentane hydrate slurry. The surfactants; Span 20, Span 40, Span 80, Tween 20, Tween 40 and Tween 80 were selected and tested to provide different hydrophilic-hydrophobic balance values and allow evaluation their solubility impact on hydrate formation and growth time. The study was performed by using a HAAKE ViscotesterTM 500 at 2 °C and a surfactant concentration ranging from 0.1 wt%-1 wt%. The solubility characteristic of the non-ionic surfactants changed the hydrate slurry in different ways with surfactants type and varying concentration. The rheological measurement suggested that oil-soluble Span surfactants was generally inhibitive to hydrate formation by extending the hydrate induction time. However, an opposite effect was observed for the Tween surfactants. On the other hand, both Span and Tween demonstrated promoting effect to accelerate hydrate growth time of cyclopentane hydrate formation. The average hydrate crystallization growth time of the blank sample was reduced by 86% and 68% by Tween and Span surfactants at 1 wt%, respectively. The findings in this study are useful to understand the rheological behavior of surfactants in hydrate slurry.

Matched MeSH terms: Solubility
Adsorption and desorption of malachite green by using chitosan-deep eutectic solvents beads

Sadiq AC, Rahim NY, Suah FBM

Int J Biol Macromol, 2020 Dec 01;164:3965-3973.
PMID: 32910963 DOI: 10.1016/j.ijbiomac.2020.09.029

Chitosan-deep eutectic solvent (DES) beads were prepared from chitosan and DESs. The DESs used were choline chloride-urea (DES A) and choline chloride-glycerol (DES B). Both chitosan-DES beads were used to remove malachite green (MG) dye from an aqueous solution. The optimum pH for chitosan-DES A was recorded at pH 8.0 while optimum pH for chitosan-DES B was pH 9.0. The maximum adsorption capacity obtained for chitosan-DES A and chitosan-DES B were 6.54 mg/g and 8.64 mg/g, respectively. The optimum conditions for both chitosan-DES beads to remove MG were 0.08 g of adsorbent and 20 min of agitation time. Five kinetic models were applied to analyse the data and the results showed that the pseudo-second-order and intraparticle diffusion model fitted best with R2 > 0.999. For the adsorption capacity, results show that the Freundlich and Langmuir adsorption isotherms fitted well with chitosan-DES A and chitosan-DES B, respectively. The maximum adsorption capacities (qmax) obtained from chitosan-DES A and chitosan-DES B were 1.43 mg/g and 17.86 mg/g, respectively. Desorption indicated good performance in practical applications.

Matched MeSH terms: Solubility

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