Recent advances in recombinant DNA technology have resulted in a great number of proteins with a potential to enter pharmaceutical formulations. The most commonly used method for preparing protein pharmaceuticals is by freeze-drying. Freezing is an important step in this process and therefore a deeper investigation of the freeze-thawing process is qualified. The aim of the thesis was to investigate the protection of protein during freeze-thawing. The effects on the recovered activity of the protein by different protective additives and different temperature history were evaluated, together with the protection mechanism on a molecular level. Lactate dehydrogenase (LDH) was used as a model protein. The systems were examined by differential scanning calorimetry (DSC and MTDSC), IR-, NMR- and fluorescence spectroscopy as well as surface tension measurements. The additives Tween 80 and Brij 35 are non-ionic surfactants and both protected LDH during freeze-thawing in concentrations far below cmc. The non-surface active polymer PEG 6000 had a protecting ability in very low concentrations. The protection was strongly affected by the temperature history; an increased freezing rate decreased the recovered activity. The optimum protecting concentration of Tween was also dependent on the cmc. During freezing below -20ºC no liquid water or amorphous ice was detected, all water was crystallized to polycrystalline ice. The relative degree of crystallinity could be determined by MTDSC at melting but not during crystallization, since it is a very fast process. An interaction between protein and additive is not necessarily required for protection at these low concentrations of additives. An interaction was observed between LDH and PEG but very weak or no interaction at all between LDH and the non-ionic surfactants. The protein was in all cases in the native state. The protective mechanisms are quite complex, but the amount of ice surface created during freezing is crucial for the protection. The non-ionic surfactants are able to hinder the protein from destructive interactions with the ice crystals by competing for adsorption at the ice surface. PEG can prevent LDH from denaturation at the ice surface by adsorption of a PEG hydrate that is formed only with certain temperature history.

The results from this thesis leads to the following conclusions; HUM is a useful tool that fills a gap in the in vitro methods previously available to study nasal drug delivery. Using HUM, the pig respiratory nasal mucosa can obtain acceptable viability and retain it longer than the period of time needed for a transport experiment. HUM has proven to be an appropriate tool for the study of liquids in low volume, gels, both unmodified and with controlled release properties, and particle suspensions. The potential local toxicity of formulations such as controlled release gels and surfactants could be evaluated and graded using HUM. The estimation of the apparent permeability can be corrected on a mathematical basis, for substances that bind to the chamber material. As seen using HUM, unmodified gels from Carbopol 934 (C934) are well tolerated by the nasal mucosa and may consequently be suitable for nasal administration. The release rate of testostenone, dihydroalprenolol and hydrocortisone from C934 gels can be successfully sustained. Protein-conjugated starch microparticles, intended to function as a vaccine carrier system, were taken up by non-ciliated epithelial cells of the pig respiratory nasal mucosa after incubation using HUM. The concentration-dependent effects on permeability and transepithelial electrical resistance on Caco-2 cells, of a series of nonionic polyoxyethylene surfactants, correlated with surfactant structure. Similar effects were seen on pig nasal mucosa using HUM, but the nasal mucosa appeared to be more tolerant to the surfactants than the intestinal cell model. The nasal route has advantages for several classes of drugs e.g. involved in migrain treatment, nicotine substitution therapy and mucosal vaccination. The increased development of a variety of substances, in a variety of formulation types, has increased the demand for suitable investigational tools. It is in this context that the horizontal Ussing chamber method (HUM) was developed. Using HUM, the studied formulation can be applied on the mucosa without additional buffer, giving an in vivo-like situation and the possibility to study solid and semi-solid formulations. Furthermore, the influence of gravity will not result in uneven distribution of the formulation.

Nasal delivery is a feasible alternative to oral or parenteral administration for some drugs because of the high permeability of the nasal epithelium, rapid drug absorption across this membrane and avoidance of hepatic first-pass metabolism. The main objective of this thesis was to investigate factors influencing the permeability of the nasal mucosa to various compounds and to evaluate implications for drug absorption via the nasal route. Porcine nasal mucosa mounted in an Ussing chamber system was established as an in vitro model, and glucose, insulin, lidocaine, mannitol, melagatran, nicotine, PEG 4000, propranolol, sumatriptan, verapamil, vinblastine and an aminodiether were used as model compounds. The pharmacokinetics of melagatran and propiomazine were investigated in absorption studies in rats, and the influence of the enhancers SDS and EDTA on melagatran absorption was evaluated and compared with in vitro permeability data. The expression of P-glycoprotein in porcine nasal mucosa was investigated and compared with that in human nasal epithelial biopsies using the Western Blot technique. The results demonstrated that the Ussing chamber model using porcine nasal mucosa has potential as a tool for evaluating mechanisms of nasal absorption and predicting the in vivo effects of absorption enhancers. Moreover, porcine nasal mucosa is comparable to human nasal mucosa in its morphology and P-glycoprotein expression. The in vitro permeability data were found to weakly correlate with literature data on human absorption after nasal administration of the corresponding compounds. In vivo absorption studies of the sedative propiomazine demonstrated that nasal administration of this drug offers an interesting alternative to the oral formulation currently on the market, since the absorption was rapid and the bioavailability was promising. The bioavailability of melagatran in rats was moderate but variable, and responded to the addition of enhancers. Finally, the establishment and characterisation of an in vitro method for prediction of nasal drug absorption, and the investigation of factors influencing nasal membrane permeability and absorption offer substantial contributions for nasal drug delivery.

Drug delivery to nasal or ocular mucosa for either local or systemic action faces many obstacles – these routes are protected by effective mechanisms. Gel formulations with suitable rheological and mucoadhesive properties increase the contact time at the site of absorption. However, drug release from the gel must be sustained if benefits are to be gained from the prolonged contact time. The work presented here is the characterization of gels and the determination of the mucoadhesive properties of polymers using rheology. Gelrite gels were formed in simulated tear fluid at concentrations of polymer as low as 0.1%, and it was shown that sodium was the most important gel-promoting ion in vivo. Rheology, although it may be a questionable technique for evaluating mucoadhesive properties of polymers, showed that interactions between mucin and polymers were most likely to be seen with weak gels. It was possible to control the release of uncharged drug substances by including surfactants that form micelles in the gel. This release depended on lipophilic interactions between the drug and the polymer and/or the micelles. Controlled-release formulations of charged drugs could be designed by mixing the drugs with oppositely charged surfactants in certain ratios. In this way, vesicles in which the drug and surfactant constituted the bilayer formed spontaneously. The vesicle formation was affected by the presence of polymer, and very small vesicles that gave a slow release rate were formed when a lipophilically modified polymer was used. The gels were also evaluated in the Ussing chamber using porcine nasal mucosa. The rate of transport of drugs through the mucosa could be controlled by the rate of release from the formulation. Furthermore, the Ussing chamber could be used to evaluate the potential toxicity of formulations.

Diss.--Technische Hochschule, Brunswick.

Thesis (M.A.)--Central Connecticut State University, 2001. / Thesis advisor: Michael Davis. " ... in partial fulfillment of the requirements for the degree of Master of Arts in Biology." Includes bibliographical references (leaves 39-41).

Thesis (M.S.)--University of Wisconsin--Madison, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 70-72).

Class of 2017 Abstract / Objectives: To assess the University of Arizona College of Pharmacy (UA COP) students’ attitudes toward, perceptions of, and interest in compounding pharmacy and to describe the influence of’ experience in compounding pharmacy. Methods: Questionnaires were administered during a regularly scheduled class. Students rated their opinions on the level of regulation of compounding pharmacies and the quality of patient care provided by compounding pharmacists compared to that provided by traditional community pharmacists, as well as their attitudes towards recommending a compounding pharmacy to a patient, family member, and himself/herself. Students also indicated their interest in learning and working in a compounding pharmacy. The survey was approved by the University IRB. Results: A total of 242 students completed the questionnaire, an 81% response rate. The 2nd and 3rd year students had significantly more experience in compounding pharmacy than the 1st year students (p=0.016). Students (92%) who had experience in compounding pharmacy, believed that compounding pharmacies are much more regulated compared to other pharmacies (p<0.001). Students with or without experience were interested in learning more about compounding pharmacy (p=0.14); however, students with experience were more interested in working in a compounding pharmacy (p<0.01).Attitudes towards and perceptions of quality of care of compounding pharmacy were similar. Conclusions: UA COP students have positive attitudes toward, perceptions of, and interest in compounding pharmacy and students’ experiences in compounding pharmacy influenced their interest in learning and working in a compounding pharmacy.