María José ARIAS Blanco

University of Seville | US · Pharmacy and Pharmaceutical Technology

Hot Stage Microscopy (HSM) is an analytical technique to perform a solid-state physical characterization of materials as a function of temperature. The formulations of poorly water soluble drugs (Triamterene) with hydrophilic carriers (PEG 6000 or β-Cyclodextrin) to obtain solid dispersions or inclusion complex, respectively, have been frequently u...

The aqueous solubility of the pesticide 2,4-D was improved by inclusion complexation with α-CD. The formation of such inclusion compounds was studied via the phase-solubility diagram (solution state) and by DSC and HSM (solid state). 2,4-D presented a typical Bs Higuchi solubility curve, coprecipitating a 1:2 pesticide-α-CD complex. In order to obt...

The inclusion complexes of both optically active and racemic mandelic acids with α-, (β- and γ-cyclodextrins were prepared by using a liophylisation technique. The compounds formed were investigated by thermoanalytical methods (TG, DSC and EGD) which were completed with FT-IR spectroscopic measurements, scanning electron microscopic observations, a...

Techniques of DSC, TG/DTG, EGD and HSM were used to study and characterize the complex formation and state of dispersion after co-grinding of a 1:1 mixture of omeprazole (OME) and γ-cyclodextrin (γ-CD) under various conditions. The changed crystalline properties of the composites obtained by co-grinding suggested distinct types of interactions betw...

This work involves the study of elaboration and thermal characterization of Gelucire® -cinnarizine (10, 20, 30, 40 and 50%, w/w cinnarizine) binary systems (solid dispersions and physical mixtures). The analytical thermal techniques employed, differential scanning calorimetry (DSC) and hot stage microscopy (HSM) have demonstrated the ability of mel...

The inclusion behaviour in water solution and in solid state of oxazepam (Ox) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) has been investigated. The complexation in solution was studied by phase solubility and by spectral shift techniques. The apparent stability constants, Kc, calculated by these techniques, are 145 and 476 M−1, respectively. The...

Complex formation of oxazepam and β-cyclodextrin in solution was studied by phase solubility and spectral shift methods. The value of the apparent stability constant, Kc, calculated using these techniques, was 205 and 498 M−1, respectively. Solid complexes of oxazepam and β-CD were prepared using the kneading and spray-drying methods. These complex...

In this paper, we illustrate the usefulness of spray-drying as a resourceful procedure for preparing solid dispersions. The study in the solid state of the triamterene-D-mannitol system from 10 to 40% w/w drug included scanning electron microscopy (SEM), X-ray diffraction (DRX) and differential scanning calorimetry (DSC). The main finding arising f...

Triamterene-urea solid dispersions of varying weight fractions were elaborated by the melting carrier method and their dissolution profiles compared with the pure drug and physical mixtures. The dissolution rates of triamterene from solid dispersions were faster than the pure drug and physical mixtures. Solubility studies revealed a linear increase...

Abstract The inclusion complex formation between oxazepam (Ox) and heptakis (2,6-di-O-methyl)-β-cyclodextrin (DIMEB) was studied in solution by solubility and ultraviolet spectroscopy methods, and in the solid state by differential scanning calorimetry, scanning electron microscopy, and powder x-ray diffractometry. The apparent stability constant,...

This paper studies the effect of molecular mass on the melting temperature, enthalpy and entropy of hydroxy-terminated poly(ethylene oxide) (PEO). It aims to correlate the thermal behaviour of PEO polymers and their variation of molecular mass (MW). Samples ranging from 1500 to 200,000 isothermally treated at 373 K during 10 min, were investigated...

The possibility of obtaining inclusion complexes between omeprazole (OME) and gamma-cyclodextrin (gamma-CD) by kneading, spray-drying, coprecipitation, and freeze-drying was evaluated. All these methods lead to the isolation of a true inclusion compound, as evidenced by differential scanning calorimetry (DSC), infrared spectroscopy, and X-ray diffr...

The inclusion complexes of ursodeoxycholic acid (UDCA) with beta-cyclodextrin (betaCD) coprecipitated with choline dichloride (CDC) or beta-cyclodextrin were investigated to evaluate the effect of the presence of choline for UDCA inclusion in betaCD. The inclusion complexes were investigated in solution by phase solubility diagrams and 1H NMR spect...

The effect of cyclodextrin (Cd) complexation on ibuproxam (IBUX) dissolution properties was studied by evaluating both the influence of Cd cavity size and the preparation method used for obtaining solid inclusion complexes. Binary systems of IBUX with natural Cds, prepared using different techniques (kneading, sealed-heating, spray-drying), were st...

In the last years pharmaceutical modification of drug molecules as guest by inclusion complexation with cyclodextrins (CD) as host, has been extensively developed to improve their dissolution rate, chemical stability and/or volatile reduction [1]. In a similar way, pesticides can be complexed into the hydrophobic cavity with the subsequent increase...

Inclusion complexes of pesticides with cyclodextrins (CDs) frequently results in advantageous modification of chemical and physical properties of these compounds. Some papers have been published about these aspects: Kamiya et al.(1) have demonstrated that the inclusion effects of β-CD inhibits the photodegradation rate of paration but promotes that...

NMR techniques are widely employed for the study of the inclusion phenomena of many drugs with CDs [1,2]. In our case, these ones were used for the elucidation of the nature of interaction between Omeprazole (OME) and ß-CD.

Chemical analysis, DSC and solubility determinations have been applied to the study of solid inclusion complexes of a pesticide, 2,4-dichlorofenoxyacetic acid (2,4-D) as guest, and β-cyclodextrin (β-CD) as host, in order to produce experimental evidence of the inclusion process and of the stoichiometry of the inclusion compound. Three processing me...

Oxazepam is a drug characterised by its marked hydrophobicity and unsatisfactory wettability on contact with water. These properties lead to incomplete absorption of the drug from the gastrointestinal tract when the pharmaceutical dosage form is not adequately formulated. For this reason, it is of interest to optimise its dissolution properties. Fo...

Gliclazide/β-CD systems were prepared by various techniques: kneading, co-grinding, spray-drying, coprecipitation and neutralization. The thermal behaviour of these systems was studied by using DSC and TG, in order to find occurrence of the occurrence of solid-state inclusion complexation. The use of a complementary technique, Fourier transform inf...

The aqueous solubility of the pesticide 2,4-D was improved by inclusion complexation with α-CD. The formation of such inclusion compounds was studied via the phase-solubility diagram (solution state) and by DSC and HSM (solid state). 2,4-D presented a typical Bs Higuchi solubility curve, coprecipitating a 1:2 pesticide-α-CD complex. In order to obt...

Several derivatives containing a new organic ring system, the tropane-6-spiro-5′-hydantoin structure (namely 8-alkyl-8-azabicyclo [3.2.1.] octane-6-spiro-5′-imidazoline-2′,4′-diones) have been characterized by thermal (DSC and simultaneous DTA-TG-DTG) and spectroscopic techniques (IR,1 H-NMR,13 C-NMR). X-ray powder diffraction and elemental analysi...

Several derivatives containing a new organic ring system, the tropane-6-spiro-5′-hydantoin structure (namely 8-alkyl-8-azabicyclo [3.2.1.] octane-6-spiro-5′-imidazoline-2′,4′-diones) have been characterized by thermal (DSC and simultaneous DTA-TG-DTG) and spectroscopic techniques (IR, 1H-NMR, 13C-NMR). X-ray powder diffraction and elemental analysi...

Complex formation of triamterene and β-cyclodextrin in solution was studied by phase solubility and spectral shift methods. The value of the apparent stability constant, Kc, calculated by these techniques, were 340 and 470 M−1, respectively. Binary systems of triamterene and β-CD were prepared using the dry co-grinding method. Their characterizatio...

A thermal study using DSC and Hot Stage Microscopy (HSM) was carried out to investigate the interaction in solid state of the binary system PEG 4000 — oxazepam, and to establish their phase diagram. The eutectic composition, which melting occurs at lower temperature as compared with the pure components, has been determined. The results obtained by...

A critical issue in the processing of solid dispersions is to elucidate the microstructure of the resulting product. Morphological features such as crystallinity degree of both carrier and drug, and particle size of the latter, have a deep effect on the properties of the drug dissolution. In the present paper, Hot Stage Microscopy (HSM) has been em...

The applicability of the solid dispersion technique as a method for enhancing the GI absorption of a drug has been explored in order to procure better dissolution characteristics and better bioavailability for triamterene. The physicochemical characterization of the systems has shown the absence of chemical reaction between the drug and the polymer...

In this work, matrix tablets have been prepared with binary mixtures of the inert polymer Eudragit RS 100 and a soluble, power-conductor model substance, sodium chloride. The sodium chloride content was between 20 and 80% w/w. Two techniques have been proposed to achieve an easy estimation of the values of percolation thresholds, as a function of t...

The interaction of the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) with β-Cyclodextrin produces the formation of a new inclusion compound in solution and in solid state. XRD, MR, DSC and SEM techniques have allowed to investigate the inclusion process of the three processing methods (co-precipitation, spray-drying and kneading) under test. Inc...

In the present study, the effect of the molecular weight and thermal treatments on commercial polyethylene glycols (PEG) samples used in the pharmaceutical processing technology, has been analyzed using DSC and HSM. The molecular weight of these polymers range from 1500 to 200000. Thermal investigations on the melting behavior of original PEG sampl...

The study of complexation between GL and ß-CD in liquid medium has been carried out by phase-solubility,1H and13C NMR studies. A formation complex is observed from the phase solubility diagram, being the average association constant of 1094 M-1, The NMR studies revealed the preferent complexation of the aliphatic moiety of GL. The aromatic moiety i...

The study of complexation between GL and ß-CD in liquid medium has been carried out by phase-solubility, 1H and 13C NMR studies. A formation complex is observed from the phase solubility diagram, being the average association constant of 1094 M−1. The NMR studies revealed the preferent complexation of the aliphatic moiety of GL. The aromatic moiety...

The interaction of the herbicide 2, 4-D with α-CD investigated by phase solubility, XRD and DSC indicate that 2, 4-D forms an inclusion complex with α-CD by coprecipitation and spray-drying methods. These complexes exist in solution with 1:1 and 1:2 stoichiometry and in the solid phase with 1:2 stoichiometry. The calculated values of stability cons...

The formation of crystalline inclusion complex of triamterene with β-cyclodextrin (β-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triameterene with β-CD were prepared in 1∶1 molar ratio. The changes of crystalline...

The complexation behaviour of Oxazepam (Ox) with γ-cyclodextrin (γ-CD) was investigated in solution and in solid phase by means of Phase-solubility techniques, UV spectroscopy, 1H NMR spectroscopy, Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and powder X-Ray Diffractometry (XRD). The binary systems Ox-γ-CD were prepa...

The present investigation was designed and undertaken in order to substantiate further contention concerning the universality of the utilization of PEG polymers as matrix carriers. This study could then be considered an attempt to enhance the dissolution rate of triamterene, with the subsequent enhancement in its absorption rate, via solid dispersi...

Present paper proposes a new system to administer triamterene, a sparing potassium diuretic which presents absorption problems when administered as a free powder, due to its low solubility in water. To increase the dissolution rate and subsequent oral bioavailability of this drug, it has been formulated as solid dispersion. This method involves pre...

Thermal analysis (DSC and HSM), and equilibrium solubility determinations were carried out to elucidate the mechanism of interaction at the solid state in the binary system triamterene-D-mannitol. Physical mixtures (5–90% w/w triamterene) and solid dispersions (5 up to 40% w/w triamterene) were prepared and studied. From DSC and HSM results, the th...

This paper examines binary polyethyleneglycol (molecular weight 6000)-Triamterene (PEG 6000-T) solid dispersions (5–40 w/w% of T) prepared by the fusion carrier method, and physical mixtures (5–90 w/w% of T) are studied using DSC and Hot Stage Microscopy (HSM). The use of these combined techniques allows to explain the thermal behaviour on the basi...