Principles of Drug Degradation

Loftsson, Þorsteinn

doi:10.1016/b978-0-12-411548-4.00002-7

Cited by 5 publications

(4 citation statements)

References 16 publications

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“…The value of K 1:2 is often in the range 10 to 500 M −1 or significantly lower than that of K 1:1 (4) Determination of the complexation efficiency (CE) can be a better alternative to K 1:1 to compare the solubilizing effect of CDs . The CE determination (Equation ( 5)) has less variation because it can be calculated from only the slope of the linear phase-solubility diagram Loftsson, 2014;UEKAMA and HIRAYAMA, 1987).…”

Section: Solubility Studiesmentioning

confidence: 99%

Stability characterization, kinetics and mechanism of tacrolimus degradation in cyclodextrin solutions

Prajapati

Eiríksson²,

Loftsson

2020

International Journal of Pharmaceutics

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Tacrolimus is a macrolide lactone and potent immunosuppressant. It is highly lipophilic and has very limited aqueous solubility. Tacrolimus is highly susceptible to hydrolysis which results in very limited stability in aqueous solutions. Besides this, tacrolimus also undergoes dehydration and epimerization. Cyclodextrin (CD) complexation can increase the solubility and stability of hydrophobic drugs in aqueous solutions through the formation of drug/CD complexes. The aim of this study was to investigate degradation kinetics, mechanism and stability of tacrolimus in aqueous CD solutions, with the ultimate goal of developing an aqueous vehicle for ophthalmic delivery. For this, phase-solubility and kinetic studies in aqueous solutions containing different CDs at different pH values were performed. Mass spectrometry studies were also performed to elucidate the degradation mechanism of the drug in aqueous CD solution. The study showed that the drug has maximum stability between pH 4 and 6 and hydrolysis was the main cause of tacrolimus degradation in aqueous 2-hydroxypropyl-βCD (HPβCD) solutions. βCD and its derivatives were the better CD solubilizers for tacrolimus. The solubility and stability studies were further conducted with CD and surfactants, which is tyloxapol, tween 80 and poloxamer 407, where the combination provided better results compared to individual components.

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Section: Solubility Studiesmentioning

confidence: 99%

Stability characterization, kinetics and mechanism of tacrolimus degradation in cyclodextrin solutions

Prajapati

Eiríksson²,

Loftsson

2020

International Journal of Pharmaceutics

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“…The degradation pace of the scaffolds has some control over drug release, and the degradation rate can be impacted by different factors like temperature, pH, polymer type, enzymes, and the presence of nanoparticles. 37 Figure 5E shows how electrospun mats containing 0−5% TbNs were degraded during 30 days. During the first 3 days, G0, G1, and G2 showed a faster and similar trend in degradation (around 30%) while G3 demonstrated a slow degradation rate (around 15%).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Fabrication of PEGylated SPIONs-Loaded Niosome for Codelivery of Paclitaxel and Trastuzumab for Breast Cancer Treatment: In Vivo Study

Masoumi Godgaz,

Asefnejad,

Bahrami

2024

ACS Appl. Bio Mater.

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There is a growing appeal for engineering drug delivery systems for controlled and local drug delivery. Conjugation of antibodies on the nanocarriers for targeted chemotherapeutic drugs has always been one of the main techniques. This work aims to develop a polycaprolactone/chitosan electrospun mat incorporated with paclitaxel/Fe 3 O 4 -loaded niosomes (SPNs) decorated with trastuzumab (TbNs) for cancer therapy. SPNs and TbNs were analyzed by DLS, zeta potential, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Fabricated mats with distinct concentrations of TbNs were classified into four groups (G0 (0), G1 (1), G2 (2.5), and G3 (5%)) and were studied physicochemically, mechanically, and biologically. Paclitaxel release was also studied for 7 days under an alternative magnetic field (AMF). The optimized mat was nominated for an in vivo study to evaluate its tumor growth inhibition. Based on the results, the TbNs had a spherical core and shell morphology with a smooth surface. The zeta potential and the mean size of TbNs were equal to −14.7 mV and 221 nm. TbNs did not affect the morphology and quality of nanofibers, but in general, the presence of TbNs increased the elastic modulus, water uptake, and degradation. Regarding the release study, AMF showed a significant increase in accelerating paclitaxel release from mats, and most releases belonged to the mat with 5% of TbNs. Results from the in vivo study showed the effective and synergistic effects of AMF on drug release and significant tumor growth inhibition. To summarize, the proposed nanocarrier under AMF can be a good candidate for cancer therapy.

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“…Similarly, the potential effects of any residual near-infrared (NIR) radiation on the drug will depend on the physicochemical features of the medication. It is worthwhile noticing that this wavelength range has been sought as a viable alternative to other wavelengths for drug delivery owing to its deeper transdermal penetration [ 49 , 50 ]. In this sense, the proposed DDDs may offer an advantage over other light-triggered devices.…”

Section: Resultsmentioning

confidence: 99%

Photomechanical Polymer Nanocomposites for Drug Delivery Devices

et al. 2021

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We demonstrate a novel structure based on smart carbon nanocomposites intended for fabricating laser-triggered drug delivery devices (DDDs). The performance of the devices relies on nanocomposites’ photothermal effects that are based on polydimethylsiloxane (PDMS) with carbon nanoparticles (CNPs). Upon evaluating the main features of the nanocomposites through physicochemical and photomechanical characterizations, we identified the main photomechanical features to be considered for selecting a nanocomposite for the DDDs. The capabilities of the PDMS/CNPs prototypes for drug delivery were tested using rhodamine-B (Rh-B) as a marker solution, allowing for visualizing and quantifying the release of the marker contained within the device. Our results showed that the DDDs readily expel the Rh-B from the reservoir upon laser irradiation and the amount of released Rh-B depends on the exposure time. Additionally, we identified two main Rh-B release mechanisms, the first one is based on the device elastic deformation and the second one is based on bubble generation and its expansion into the device. Both mechanisms were further elucidated through numerical simulations and compared with the experimental results. These promising results demonstrate that an inexpensive nanocomposite such as PDMS/CNPs can serve as a foundation for novel DDDs with spatial and temporal release control through laser irradiation.

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Principles of Drug Degradation

Cited by 5 publications

References 16 publications

Stability characterization, kinetics and mechanism of tacrolimus degradation in cyclodextrin solutions

Stability characterization, kinetics and mechanism of tacrolimus degradation in cyclodextrin solutions

Fabrication of PEGylated SPIONs-Loaded Niosome for Codelivery of Paclitaxel and Trastuzumab for Breast Cancer Treatment: In Vivo Study

Photomechanical Polymer Nanocomposites for Drug Delivery Devices

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