Dynamic responses of the MR Elastomers and MR gel have been studied care- fully by various research groups. However, to understand completely the dynamic response of the material, it is important to have a clear understanding of quasi-static response of the material. Thus, for the current work, we have studied quasi-static response of the MR gel. For current setup, 27 samples were prepared using Septon, plasticizer and magnetic particles and were tested for 3 rounds over 3 different magnetic fields under plane strain compression. The results from plane strain compression show linear increase in the load taken with the increase in concentration of magnetic particles in absence of any magnetic field. The response characteristics under uniform magnetic field showed a huge leap in the load taken for particular deflection. To study the quasistatic respose, the material is assumed to behave like an isotropic hyperelastic response. Field dependent Neo-Hookean and field dependent Valanis Landel models have been fit to the data, and it was found that simple 1-term field dependent Valanis Landel model with power law coefficient as four agrees well with the shear modulus obtained from experiments. The shear modulus of MAP from the Valanis Landel and Neo Hookean model was assumed to be linearly dependent on the concentration of magnetic particles and magnetic field, and this matched the experimental data well.

In this work, transparent and rigid organogels suitable for intravitreal drug delivery applications were produced with pharmaceutical/food grade polar and amphiphilic solvents with HLB values ranging from 0-19. Maximum sterol solubility was obtained with solvents with approximately HLB=6. Solvents with high sterol solubility also required higher sterol concentrations to produce a gel. However, the strength of all the organogels increased with increasing sterol concentration. Furthermore, DSC and SAXS data suggest that the structure of all the organogels was similar. An in vitro release of dexamethasone was performed over a 5.5 month period using novel organogel- dexamethasone implants. The release of dexamethasone varied from 2 to 5.5 months (or more) depending on the organogel used for the implant. These multiple-month release in vitro profiles are comparable and/or exceed the release of commercially available and FDA approved dexamethasone delivery system Ozurdex (~2 month dexamethasone release).

In this work, transparent and rigid organogels suitable for intravitreal drug delivery applications were produced with pharmaceutical/food grade polar and amphiphilic solvents with HLB values ranging from 0-19. Maximum sterol solubility was obtained with solvents with approximately HLB=6. Solvents with high sterol solubility also required higher sterol concentrations to produce a gel. However, the strength of all the organogels increased with increasing sterol concentration. Furthermore, DSC and SAXS data suggest that the structure of all the organogels was similar. An in vitro release of dexamethasone was performed over a 5.5 month period using novel organogel- dexamethasone implants. The release of dexamethasone varied from 2 to 5.5 months (or more) depending on the organogel used for the implant. These multiple-month release in vitro profiles are comparable and/or exceed the release of commercially available and FDA approved dexamethasone delivery system Ozurdex (~2 month dexamethasone release).

Šio darbo tikslas buvo ištirti hidrofilinių gelių pritaikymo galimybes transderminiam meloksikamo vartojimui. Gelių gamybos metu buvo taikomas temperatūros keitimo metodas. Visi hidrogeliai gaminami pagal pasirinktą 1,1 Pa•s ±15 proc. klampą. Meloksikamo mėginių analizė atliekama naudojant UV spektrofotometrijos metodą, puskiečių vaisto formų kokybiniam ir biofarmaciniam įvertinimui atliekami pH, dinaminės klampos, dalelių dydžio, gelių vienalytiškumo nustatymo testai, vaistinės medžiagos atsipalaidavimo tyrimai in vitro ir skvarbos į odą tyrimai ex vivo. Bandymo rezultatai parodė, kad meloksikamo hidrogelių, kuriuose vaistinė medžiaga įvesta tirpalo forma, pH siekė 6,24-6,70, suspensine forma – 5,45- 6,89. Atlikus klampos matavimą, paaiškėjo, kad įvedus meloksikamą į puskietę sistemą, jos klampa padidėja. Atpalaidavimo tyrimų in vitro metu buvo nustatyta, kad iš hidrogelio su natrio karboksimetilceliulioze (50-200 cP) per 120 min. atsipalaidavo 57,8 ± 4,5 proc. meloksikamo, su natrio karboksimetilceliulioze (200-400 cP) – 36,9± 2,2 proc., su metilceliulioze - 35,5 ±4,1 proc., su hidroksipropilmetilceliulioze – 33,4 ± 1,3 proc., su poloksameru 407 - 14,2 ± 2,3 proc. Iš hidrogelių, kuriuose meloksikamas įvestas suspensine forma, natrio karboksimetilceliuliozės (50-200 cP) sudėtyje turintis gelis atpalaidavo 20,3±4,7 proc. vaistinės medžiagos. Atlikus skvarbos tyrimą ex vivo, iš kontrolinio meloksikamo tirpalo prasiskverbė 0,96 proc. medžiagos, iš hidrogelio tikslaus... [toliau žr. visą tekstą] / The aim of this work was to investigate the application of hydrogels for meloxicam transdermal use. Gels were prepared using temperature mixing method. All types of gels were made according to established viscosity of 1,1 Pa•s ±15 %. The quantitative determination of meloxicam was performed by UV spectrofotometry method. Characterisation of prepared gels was evaluated by pH measurement, viscosity, particle size analysis, in vitro drug release and ex vivo skin permeation studies. Results showed that the pH of the prepared gel formulations was in the range of 6,24-6,70 in liquid form incorporated meloxicam and in the form of suspension 5,45-6,89. Viscosity measurement showed that meloxicam increases the viscosity of semisolid preparations. In vitro release studies showed that the hydrogel with sodium carboxymethylcellulose (50-200 cP) over 120 min relaxed 57,8 ± 4,5% of meloxicam, with sodium carboxymethylcellulose (200-400 cP) – 36,9± 2,2 %, with methylcellulose - 35,5 ± 4,1 %, with hydroxypropilmethylcellulose – 33,4 ± 1,3 %, with poloxamer 407 - 14,2 ± 2,3 %. Suspension type hydrogel of meloxicam with a sodium carboxymethyl cellulose (50-200 -cP) relaxed 20,3 ± 4,7 % drug substances. During the experiment were prepared similar to the skin pH meloxicam hydrogels. In vitro studies have shown that the incorporating meloxicam in gel by suspension do not provide sufficient drug substance release. Diffusion rate of drugs generally depends on the physical structure of the... [to full text]

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 6 uppsatser.

Thesis (Ph. D.)--Auburn University. / Abstract. Includes bibliographical references.

Thèse (Ph. D.)--Université Laval, 2008. / Bibliogr.: f. 130-140. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.

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