The mechanism of steroid transport and corticosterone secretion in the zona fasciculata-reticularis of rat adrenal cortex was investigated by measuring the subcellular distribution and concentrations of steroids following ACTH stimulation.

No description available.

Eczema or dermatitis is the most common dermatological condition accounting for one-third of all diagnoses in the total population surveyed in South Africa. The prevalence of seborrhoeic dermatitis, extreme photodermatitis and severe psoriasis has increased markedly over the last decade and this increase may be ascribed to the HIV epidemic, first diagnosed in South Africa in 1982. Potent innovator corticosteroids, such as clobetasol 17-propionate (CP) that are used to treat skin disorders, are expensive and there is therefore a need for the production of generic topical corticosteroid products. Formulation and manufacturing processes can be challenging aspects for formulation scientists to produce a robust product that will elicit an appropriate and desirable pharmacokinetic-pharmacodynamic profile. Laboratory scale CP creams were manufactured using different concentrations of Gelot® 64 and propylene glycol in order to establish a composition that would produce a formulation, with similar physical and chemical characteristics and in vitro release profile as an innovator product, Dermovate®. These formulations were assessed in terms of their viscosity, spreadability, pH, content uniformity and in vitro release characteristics using a Franz diffusion cell apparatus. A formulation containing 3% w/w Gelot® 64 and 46% v/v propylene glycol (CPLS-02) was found to exhibit similar viscosity and spreadability characteristics and released CP in a manner similar to Dermovate®. The mechanism of drug release was evaluated using mathematical models such as zero order, first order and Higuchi models. In addition, the in vitro release profiles were characterised by use of difference (f1) and similarity (f2 and Sd) factors. A scale-up formulation with the same % w/w composition as the laboratory scale was also investigated following manufacture using a Wintech® cream/ointment mixer. A Central Composite Design approach was used to investigate the effect of process variables on the performance of the scale-up cream formulations. The homogenisation speed, anchor speed, homogenisation time and cooling time were the process variables investigated. Thirty scale-up batches were manufactured and analysed in terms of their viscosity, spreadability, pH, % drug content and cumulative % drug released per unit area over 72 hours. Model fitting using Design-Expert® software was undertaken and revealed that a correlation between the process variables and the cream responses was most suitably described by quadratic polynomial relationships. The homogenisation speed had the most significant effect on the quality of the scale-up formulations, whereas the anchor speed had a secondary effect on the measured responses, for the formulations investigated. The qualitative interpretation and statistical analysis of the in vitro release data from the scale-up formulations using ANOVA and the f1, f2 and Sd factors revealed that one scale-up batch (CPSU-04), for which the process variables were a homogenisation speed of 1900 rpm, an anchor speed of 35 rpm, a homogenisation time of 100 minutes and a cooling time of 100 minutes, released CP at a similar rate and extent to Dermovate®. A diffusion-controlled mechanism appeared to be predominant in these formulations. A human skin blanching study, using both visual and chromameter assessments, was performed to establish whether batch CPSU-04 was bioequivalent to Dermovate®. The bioequivalence of the selected scale-up formulation to Dermovate® was confirmed, following the calculation of a 90% CI.

Call number: LD2668 .T4 1952 P7 / Master of Science

Call number: LD2668 .T4 1955 B73 / Master of Science

Call number: LD2668 .T4 1965 K48 / Master of Science

published_or_final_version / Zoology / Master / Master of Science

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

Master of Dental Surgery / It has been considered for the purpose of this review unnecessary to discuss in detail the Morphology of the dental pulp and dentine, as this may be found in any recognised text-book, but to concentrate on the clinical problems involved. The materials discussed are those in current usage for exposed pulp preservation, whilst other materials may be touched upon and it is the endeavour of the author to review as many results as possible in this field and to draw sound conclusion from statements made. The field of corticosteroids in dentistry is comparatively new and here it is the aim to provide a basis from which further research may be undertaken. Thus, this thesis is divided into two distinct sections. The first section dealing with non-corticoid drugs and the second sections dealing with cortico-steriods and their combinations, exclusively, utilising the commercial product Ledermix as their prime example. However, when considering pulp therapy one must delve into the past to understand the thought and effort that has gone into this realm of dentistry and to note the lack of the true scientific attitude by some into this work. This may then allow us to look again at our own statements to note how much controversy there was, and still is concerning a question such as “should an attempt on the pulp once exposed ever be made to maintain its vitality?” It will be shown at a later stage that the pulp has marvellous recuperating powers if treated in a conservative manner, something which was hardly considered even early this century. Castognola, Quigleyand Berman have all reviewed this subject before. However, my aim is to bring together all of their information as a preface to the important work of considering the immediate study being carried out in this field. The first attempted vital capping was carried out by Philip Pfaff in 1756 with a small piece of gold foil adapted to the base of the cavity. Then in 1826 it was reported that Lenoard Koeker cauterized the exposed pulp with a hot iron wire and placed silver or lead caps over the exposures. It then appeared that little further was written concerning pulp capping until the middle of the 19th century when Albrecht (1856) utilised opiates, caustics and eugenol on the exposed pulp. McKown (1859) recommended cotton soaked in creosote and tannic acid, whilst Taft (1859) was in favour of cauterizing recently exposed pulps with nitric acid and placing a filling immediately. These results were purely a subjective evaluation. In fact Mc Kown’s results were produced on one of his own teeth. The history of pulp preservation really begins in the early 1860’s. Allport (1866) and Atkinson (1866-1868) suggested amputation of all projecting cornua of exposed pulps and placement of a temporary filling until it was healthy. Allport used the b lood clot formed during operation as his means of capping. J Foote (1866) also, believed the blood clot to be the best means of covering the pulp. This certainly appeared to be a reasonable assumption, considering medical knowledge of the day.