The physicochemical properties of oestradiol

Salole, E.G.

doi:10.1016/0731-7085(87)80076-6

Cited by 12 publications

(9 citation statements)

References 38 publications

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“…Thermomicroscopic examination by the same group suggests that there is some structural rearrangement of BES•0.5H 2 O before melting. It was therefore concluded by Salole, 16 in 1987, that BES•0.5H 2 O dehydrates in two stages. The first stage is around 112°C, and the second at ca.…”

Section: Introductionmentioning

confidence: 96%

“…The IR spectra of the two anhydrous crystalline forms (BES Form I and BES Form II) suggested that BES Form I contained an O-H group not involved in hydrogen bonding and that in BES Form II there was ketonization of the steroid A-ring. The other two crystalline forms that Smakula described as anhydrous have been identified by Salole 16 as BES•0.5H 2 O and the methanol hemisolvate (BES•0.5MeOH). Heating of any of the four forms between two rock salt plates produces a common glassy amorphous form, BES (am) .…”

Section: Introductionmentioning

confidence: 99%

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The solid state forms of the sex hormone 17-β-estradiol

Stevenson

Lancaster

Buanz³

et al. 2019

CrystEngComm

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

The solid state forms of the sex hormone 17-β-estradiol

Stevenson

Lancaster

Buanz³

et al. 2019

CrystEngComm

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“…It may seem that formation of the solvated forms of estradiol including estradiol hemihydrate occurs in aqueous solutions. However, the most characteristic property of estradiol is its tendency to adopt the hemihydrated form, which it precipitates in this state, not only from partially aqueous solutions, but also from ethyl acetate, chloroform, absolute ethanol, and other anhydrous solvents (11). It has been demonstrated that water is selectively incorporated into the lattice when estradiol crystallizes from solution and the presence of water molecules is a crucial requirement for the crystallographic stability of estradiol (21).…”

Section: Discussionmentioning

confidence: 99%

“…It should be noted that the most characteristic property of estradiol is its tendency to adopt the hemihydrated form (Fig. 2), which it precipitates in this state, not only from partially aqueous solutions, but also from ethyl acetate, chloroform, absolute ethanol, and other anhydrous solvents (11). However, the effect of adhesive layer thickness on the crystallization phenomenon has not been investigated yet.…”

Section: Introductionmentioning

confidence: 99%

Effect of Adhesive Layer Thickness and Drug Loading on Estradiol Crystallization in a Transdermal Drug Delivery System

et al. 2010

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Abstract. The effects of adhesive layer thickness and drug loading on estradiol crystallization were studied in a drug-in-adhesive patch. Patches containing different estradiol loadings (1.1% and 1.6% w/w) in different thicknesses (45, 60, and 90 μm) were prepared by coating of a homogenous mixture of adhesive solution and the drug on a siliconized release liner by a film applicator. After drying, the film was laminated on a Poly(ethylene terephthalate) backing layer and cut into appropriate size. Release tests were performed using thermostated Chien-type diffusion cells. Cross-section of the patches was observed by optical microscopy. Scanning electron microscopy was done for surface analysis of the patches after drug release test. Crystal formation was not expected in the adhesive layer based on the linear free-energy relationship formalisms however; crystalline regions were observed in different locations through the thickness of the patches. These regions were significantly more discontinuous in 45 μm samples which elucidated the effective role of adhesive layer thickness in drug crystallization. Extensive crystallization observed for thicker patches was attributed to the strong crosslinking capability of estradiol hemihydrate. Drug release study confirmed some of the crystallization results. No significant increase was observed in the burst release with increasing in thickness from 45 to 60 μm which can be attributed to the severe increase in the crystallization extent. Also, formation of a crystalline layer near the releasing surface and more discontinuous pattern of the crystals in some samples was confirmed by investigation of the drug release curves.

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“…These peaks are observed in the lower wave number region, as mentioned above. For example, in the spectrum of EH, which is known to be crystalline, 18 the peaks at 110, 91, and 71 cm −1 correspond to lattice modes. These peaks are very weak in the AE spectrum.…”

Section: Physical Nature Of the Solid Inclusionsmentioning

confidence: 98%

Crystallization of ?-estradiol in an acrylic transdermal drug delivery system

Varíankaval

Jacob

Dinh

1999

J. Biomed. Mater. Res.

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Transdermal drug delivery systems are pharmaceutical products that can deliver controlled doses of drugs from polymeric patches applied on the human skin. The long-term stability of these patches is a critical issue relative to their performance in delivering drugs at a constant rate. Where a drug has been dissolved in the polymeric adhesive patch, crystallization has been reported in several systems. This study uses a variety of characterization tools to determine the physical and chemical nature of the precipitates formed in situ in estradiol patches. Optical microscopy revealed that crystals were formed in a single layer inside the adhesive matrix and that there were two distinctly different morphologies: needle-like crystals and aggregates around the needles. From IR measurements it was evident that estradiol probably was present in more than one crystal form in these patches. Raman microscopy showed that the needle-like crystals contain the adhesive component and the aggregates some modified crystal form of estradiol, indicating that in addition to the drug, the polymeric adhesive also crystallizes during storage.

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The physicochemical properties of oestradiol

Cited by 12 publications

References 38 publications

The solid state forms of the sex hormone 17-β-estradiol

The solid state forms of the sex hormone 17-β-estradiol

Effect of Adhesive Layer Thickness and Drug Loading on Estradiol Crystallization in a Transdermal Drug Delivery System

Crystallization of ?-estradiol in an acrylic transdermal drug delivery system

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