18 research outputs found
Hydrophobic ion pairing as a strategy to improve the encapsulation efficiency of PLGA nanoparticles.
Get PDFUniverzita Karlova Farmaceutická fakulta v Hradci Králové Katedra farmaceutické technologie Autorka: Lizaveta Laviaha Název práce: Hydrofobní iontové párování jako strategie pro zlepšení enkapsulační účinnosti PLGA nanočástic. Školitelka: PharmDr. Eva Šnejdrová, Ph.D. Konzultant: Mgr. Vladislav Frolov Cílem diplomové práce bylo zvýšit enkapsulační účinnost (EE) a kapacitu PLGA nanočástic (NČ) pro hydrofilní antibiotika gentamicin (GEN) a vankomycin (VAN). Byla zvolena metoda hydrofobního iontového párování (HIP) a dokusát sodná sůl ve funkci anionického tenzidu (AOT). Byly připraveny PLGA nanočástice inkorporované VAN nebo GEN nebo jejich komplexy s AOT optimalizovanými metodami. Nanočástice s VAN a GEN byly připraveny dvojitě-emulzní metodou (V1/O/V2), pro GEN-AOT byla požita metoda jednoduché emulgace (O/V) a nanočástice s VAN-AOT byly připraveny suspenzně-emulzní metodou (S/O/V). Byly získány stabilní NČ o velikosti 108 až 223 nm s polydisperzitou nižší než 0,2. Byl zjištěn vliv koncentrace PLGA na velikost NČ. Nízký zeta potenciál nanočástic souvisí se sterickou stabilizací neionogenním stabilizátorem Poloxamer 407. Snímky SEM potvrdily sférický tvar NČ. Enkapsulační účinnost a kapacita polymeru pro léčivo (LC) byly stanoveny přímou metodou. VAN a jeho komplex byly analyzovány pomocí HPLC, GEN...Charles University Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Author: Lizaveta Laviaha Title of thesis: Hydrophobic ion pairing as a strategy to improve the encapsulation efficiency of PLGA nanoparticles. Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Сonsultant: Mgr. Vladislav Frolov The aim of this thesis was to increase the encapsulation efficiency (EE) and capacity of PLGA nanoparticles (NPs) for the hydrophilic antibiotics gentamicin (GEN) and vancomycin (VAN). The method of hydrophobic ion pairing (HIP) and docusate sodium as anionic surfactant (AOT) were chosen. PLGA nanoparticles loaded with VAN or GEN, or their AOT complexes were prepared with optimized methods. Nanoparticles with VAN and GEN were prepared by the double-emulsion method (W1/O/W2), for GEN-AOT the single emulsion method (O/W) was used, and nanoparticles with VAN-AOT were prepared by suspension-emulsion method (S/O/W). Stable NPs with a size of 108 to 223 nm with a polydispersity lower than 0.2 were obtained. The influence of PLGA concentration on the size of NPs was found. The low zeta potential of the nanoparticles was related to steric stabilization by the non-ionogenic stabilizer Poloxamer 407. SEM images confirmed the spherical shape of the NPs. Encapsulation efficiency and loading capacity...Department of Pharmaceutical TechnologyKatedra farmaceutické technologieFarmaceutická fakulta v Hradci KrálovéFaculty of Pharmacy in Hradec Králov
Hydrophobic ion pairing as a strategy to improve the encapsulation efficiency of PLGA nanoparticles.
No full textCharles University Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Author: Lizaveta Laviaha Title of thesis: Hydrophobic ion pairing as a strategy to improve the encapsulation efficiency of PLGA nanoparticles. Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Сonsultant: Mgr. Vladislav Frolov The aim of this thesis was to increase the encapsulation efficiency (EE) and capacity of PLGA nanoparticles (NPs) for the hydrophilic antibiotics gentamicin (GEN) and vancomycin (VAN). The method of hydrophobic ion pairing (HIP) and docusate sodium as anionic surfactant (AOT) were chosen. PLGA nanoparticles loaded with VAN or GEN, or their AOT complexes were prepared with optimized methods. Nanoparticles with VAN and GEN were prepared by the double-emulsion method (W1/O/W2), for GEN-AOT the single emulsion method (O/W) was used, and nanoparticles with VAN-AOT were prepared by suspension-emulsion method (S/O/W). Stable NPs with a size of 108 to 223 nm with a polydispersity lower than 0.2 were obtained. The influence of PLGA concentration on the size of NPs was found. The low zeta potential of the nanoparticles was related to steric stabilization by the non-ionogenic stabilizer Poloxamer 407. SEM images confirmed the spherical shape of the NPs. Encapsulation efficiency and loading capacity..
On Whitney-type Characterization of Approximate Differentiability on Metric Measure Spaces
No full textWe study approximately differentiable functions on metric measure spaces admitting a Cheeger differentiable structure. The main result is a Whitney-type characterization of approximately differentiable functions in this setting. As an application, we prove a Stepanov-type theorem and consider approximate differentiability of Sobolev, BV and maximal functions.Peer reviewe
Fractional Hardy inequalities and capacity density
Get PDFWe prove that a pointwise fractional Hardy inequality implies a fractional
Hardy inequality, defined via a Gagliardo-type seminorm. The proof consists of
two main parts. The first one is to characterize the pointwise fractional Hardy
inequality in terms of a fractional capacity density condition. The second part
is to show the deep open-endedness or self-improvement property of the
fractional capacity density, which we accomplish in the setting of a complete
geodesic space equipped with a doubling measure. These results are new already
in the standard Euclidean setting
Hardy-Sobolev inequalities and weighted capacities in metric spaces
No full textLet be an open set in a metric measure space . Our main result gives an equivalence between the validity of a weighted Hardy–Sobolev inequality in and quasiadditivity of a weighted capacity with respect to Whitney covers of . Important ingredients in the proof include the use of a discrete convolution as a capacity test function and a Maz'ya type characterization of weighted Hardy–Sobolev inequalities
Capacities and Density Conditions in Metric Spaces
No full textWe examine the relations between different capacities in the setting of a metric measure space. First, we prove a comparability result for the Riesz (β, p)-capacity and the relative Hajłasz (β, p)-capacity, for 1 < p < ∞ and 0 < β ≤ 1, under a suitable kernel estimate related to the Riesz potential. Then we show that in geodesic spaces the corresponding capacity density conditions are equivalent even without assuming the kernel estimate. In the last part of the paper, we compare the relative Hajłasz (1, p)-capacity to the relative variational p-capacity.peerReviewe
How to Recognize Polynomials in Higher Order Sobolev Spaces
No full textThis paper extends characterizations of Sobolev spaces by Bourgain, Brézis, and Mironescu to the higher order case. As a byproduct, we obtain an integral condition for the Taylor remainder term, which implies that the function is a polynomial. Similar questions are also considered in the context of Whitney jets
Fractional Hardy inequalities and visibility of the boundary
No full textWe prove fractional order Hardy inequalities on open sets under a
combined fatness and visibility condition on the boundary. We demonstrate by
counterexamples that fatness conditions alone are not sufficient for such Hardy
inequalities to hold. In addition, we give a short exposition of various fatness
conditions related to our main result, and apply fractional Hardy inequalities in
connection to the boundedness of extension operators for fractional Sobolev spaces.peerReviewe
