Use of isothermal heat conduction microcalorimetry, X-ray diffraction, and optical microscopy for characterisation of crystals grown in steroid combination-containing transdermal drug delivery systems

Latsch, Silvia; Selzer, Torsten; Fink, Lothar; Horstmann, Michael; Kreuter, Jörg

doi:10.1016/s0939-6411(03)00120-6

Cited by 10 publications

(4 citation statements)

References 35 publications

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“…The method has been already used in combination with X-ray diffraction and optical microscopy to follow the crystallization of a supersaturated steroid in a transdermal patch. 25 It should also be noted that the presence of polymers in the formulation, as well as temporally changing drug thermodynamic activity as the volatile solvent evaporates, may also influence the solubility of testosterone in the stratum corneum and hence the manner in which it partitions into the skin. Identifying the importance of these phenomena, and quantifying their impact, are experimentally challenging objectives for future research.…”

Section: In Vitro Permeation Experimentsmentioning

confidence: 99%

Impact of Antinucleants on Transdermal Delivery ofTestosterone from a Spray

Leichtnam

Rolland

Wüthrich

et al. 2007

Journal of Pharmaceutical Sciences

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Section: In Vitro Permeation Experimentsmentioning

confidence: 99%

Impact of Antinucleants on Transdermal Delivery ofTestosterone from a Spray

Leichtnam

Rolland

Wüthrich

et al. 2007

Journal of Pharmaceutical Sciences

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“…2 Departament de Farmacología, Toxicología i Química Terapèutica, Universitat de Barcelona, Joan XXIII, 27-31, Catalonia, 08028, Spain. 3 Unitat de Biofarmàcia i Farmacocinètica. Departament de Farmàcia i Tecnología Farmacèutica i Fisicoquímica, Universitat de Barcelona, Joan XXIII, 27-31, Catalonia, 08028, Spain.…”

Section: Introductionunclassified

“…In addition, oversaturation of amorphous drug can lead to physical instability, as such amorphous materials tend to crystallize in the patch (3) and drug activity and permeation decrease due to crystallization, reducing its expected skin flux due to its low dissolution rate. Although only dissolved drug molecules can permeate through the skin, some authors believe that the use of certain polymeric formulations allows for additional permeability increases over and above drug solubility that tend to be proportional to the total drug ratios (3,4). In fact, drug solubility in the polymeric matrix is a limiting factor to improve the transdermal concentration gradient.…”

Section: Introductionmentioning

confidence: 99%

Release of Ropinirole in Acrylate Transdermal Patches: Mutual Interactions Between Formulation Variables

Paterna-Paterna¹,

Miñarro-Carmona²,

Dolors³

et al. 2022

AAPS PharmSciTech

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The aim of this study is to evaluate the cooperative interactions between formulation variables of ropinirole transdermal patches and characterize the effects of drug loading and crystallinity, degree of ionization and drug-polymer solubilization, functionalization of acrylate polymeric basis, and the addition of permeation enhancers over the release profiles. Several series of transdermal films based on carboxylic or hydroxylic acrylates (DuroTak®) and containing 1 to 10% ropinirole hydrochloride were laminated by mold-casting and evaporation. Formulations were characterized for crystallinity, drug particle size, drug assay, and residual solvents. Release profiles were obtained at different drug ionization state using paddle over disk apparatus. Mechanisms were elucidated with nonlinear data fitting of relevant release equations. Fickian and erosion processes were evaluated with the Peppas–Sahlin equation, and burst release risks were estimated as an independent term added to Higuchi kinetics. X-ray diffraction and microscopy evidenced differences in drug-polymer solubilization and density of drug crystals. Concerning drug release, area under the curve of dissolved quantities and release percentage were discriminant variables in mutual influence. Peppas–Shalin equation was the majority descriptor of release suggesting a combination of Fickian and erosion processes, revealing a decrease in the Fickian component as drug loading increased. Major burst release risks were evidenced mostly with Higuchi kinetics with vinylacetate acrylates. The carboxylic polymer without vinylacetate provided the best release extent, being more highly efficient as lower the drug loading was. Permeation enhancers with carboxylic or aliphatic radicals have, additionally, modified the release properties of ropinirole. Chemical interactions between the drug and acrylic polymers have been demonstrated. Only the effect with carboxylic polymer is pH dependent. The vinyl acetate comonomer reduces the drug release rate most effectively in formulations with low drug loads. The acrylic polymers without vinylacetate achieved the highest drug solubilization and thus the highest degree of release, providing a release of approximately 15% of the drug load.

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“…Only dissolved drug molecules can permeate across the skin. Consequently, the drug activity and absorption decrease as a result of crystallization (Kim and Choi, 2002;Kotiyan and Vavia, 2001;Latsch et al, 2004). Hence, significant efforts were made to stabilize supersaturated solutions by the addition of different antinucleant polymers or other additives (Iervolino et al, 2001;Kim and Choi, 2002;Kotiyan and Vavia, 2001;Lipp, 1998;.…”

Section: Introductionmentioning

confidence: 99%

Solvent effects on physicochemical behavior of estradiols recrystallized for transdermal delivery

Park

Kang

et al. 2008

Arch. Pharm. Res.

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Previously we have recrystallized estradiol with various organic solvents and investigated solvate molecules within estradiol crystals by using CP/MAS solid-state NMR. To investigate the effect of recrystallization solvents on the physicochemical properties of recrystallized estradiol, four different crystal habits of estradiol were recrystallized and their physicochemical properties were characterized by optical microscopy, solubility, and FT-IR measurements. Various crystal habits in size and shape were produced by the interaction between the estradiol and different solvents. Although the estradiol crystal habits prepared from ethanol and methanol had larger particle size, they were more soluble in PBS than those recrystallized from isopropanol and acetone. In spite of the low solubilities, the estradiols prepared from isopropanol and acetone were released in PBS and permeated through the hairless mouse skin similar to the others. Thus, although microscopic observation of recrystallized estradiols revealed that the estradiol had different crystal habits, the release and permeation properties of different estradiol crystals might be independent on the solvate molecules associated with the solvent used for recrystallization.

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Use of isothermal heat conduction microcalorimetry, X-ray diffraction, and optical microscopy for characterisation of crystals grown in steroid combination-containing transdermal drug delivery systems

Cited by 10 publications

References 35 publications

Impact of Antinucleants on Transdermal Delivery ofTestosterone from a Spray

Impact of Antinucleants on Transdermal Delivery ofTestosterone from a Spray

Release of Ropinirole in Acrylate Transdermal Patches: Mutual Interactions Between Formulation Variables

Solvent effects on physicochemical behavior of estradiols recrystallized for transdermal delivery

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