9 research outputs found
Formulation, evaluation and characterization of an oral modified realease naproxen sodium preparation.
No full textThesis (M.Sc.)--University of Durban-Westville, 1997.The motivation for the present study is systematically presented and the aims and objectives
of the study are clearly defined. A comprehensive review on modified release drug delivery
has been presented to provide the basis for the meltable aqueous dispersion technique as an
approach to the formulation of a multiple-unit oral modified release drug delivery system.
In addition, a brief discussion on the theory of dissolution testing and the mechanisms and
interpretation of the dissolution process has been presented. Naproxen sodium, a potent
non-steroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic activity
employed in the study, has been briefly discussed.
In the present study, the coacervation phase separation technique utilizing ethylcellulose
was initially investigated but proved unsuccessful in producing a formulation displaying
suitable drug release characteristics. Subsequently, the meltable aqueous dispersion
technique utilizing cetostearyl alcohol was successfully employed to formulate a multipleunit
modified release naproxen sodium preparation containing 550 mg of naproxen sodium.
The use of cetosteary!alcohol, as·a·retarding material, generated modified ·drug release
characteristics as a function of its content. Magnesium stearate (anti-tackiness agent) and
Span 20 and Tween 60· (surfactants) were incorporated in the formulation to optimize
particle size and sphericity. The influence. of various formulation variables on drug release
characteristics were investigated:
An optimized formulation displaying a desirable modified release profile of naproxen
sodium was achieved employing a 1:1 ratio of naproxen sodium:cetostearyl alcohol, 2% m/m .. ..
magnesium stearate, and 1%m/m Span 20 dispersed in a liquid manufacturing vehicle of pH
0.6 containing 2% m/m Tween 60. In vitro dissolution studies on the selected formulation
showed drug release to be predictable and reproducible, dependent on the dissolution
method, agitation rate, and the pH of the dissolution media (i.e. pH-dependent drug
release). The density of the microspheres was shown to decrease as the concentration of
cetostearyl alcohol increased whilst the mean specific surface area increased with
increasing concentrations of cetostearyl alcohol.
Differential scanning calorimetric studies reveals a change in the thermograms which is
suggestive of eutectic formation. Scanning electron microscopy proved useful in evaluating
the integrity and surface morphology of the microspheres as well as in elucidating the drug
release characteristics of the formulation. Energy dispersive x-ray microprobe analysis
revealed the elemental composition of the microspheres to be a composite of the pure
ingredients. X-ray mapping and the line scan depicted the homogenous distribution of drug
within the microspheres and confirmed that the formulation is a matrix-type modified release I'
preparation.
Stability studies were performed on the selected formulation at room temperature
(21 :t 1°C), 40°C, 37°C with 80% relative humidity, and at low temperature (5 :t 1°C). The
shelf-life of the selected formulation was determined to be 1.29 years. Applying the data to
five different kinetic models to investigate the drug release mechanisms showed that first order
and cube-root release characteristics were exhibited by the microspheres
Conformal symmetries and classification in shear-free spherically symmetric spacetimes.
No full textM. Sc. University of KwaZulu-Natal, Durban 2014.In this thesis we study the conformal geometry of static and non-static spherically
symmetric spacetimes. We analyse the general solution of the conformal Killing vector
equation subject to integrability conditions which place restrictions on the metric func-
tions. TheWeyl tensor is used to characterise the conformal geometry, and we calculate
the Weyl tensor components for the spherically symmetric line element. The accuracy
of our results is veri ed using Mathematica (Wolfram 2010) and Maple (2009). We
show that the standard result in the conformal motions for static spacetimes is in-
correct. This mistake is identi ed and corrected. Two nonlinear ordinary differential
equations are derived in the classi cation of static spacetimes. Both equations are
solved in general. Two nonlinear partial differential equations are derived in the classi-
cation of non-static spacetimes. The rst equation is solved in general and the second
equation admits a particular solution. Our treatment is the rst complete classi cation
of conformal motions in static and non-static spherically symmetric spacetimes using
the Weyl tensor
Defining distal femoral anatomy for rotational alignment in total knee arthroplasty: a magnetic resonance imaging‐based study
No full text
Spherical conformal models for compact stars
No full textAbstract We consider spherical exact models for compact stars with anisotropic pressures and a conformal symmetry. The conformal symmetry condition generates an integral relationship between the gravitational potentials. We solve this condition to find a new anisotropic solution to the Einstein field equations. We demonstrate that the exact solution produces a relativistic model of a compact star. The model generates stellar radii and masses consistent with PSR J1614-2230, Vela X1, PSR J1903+327 and Cen X-3. A detailed physical examination shows that the model is regular, well behaved and stable. The mass–radius limit and the surface red shift are consistent with observational constraints
TRENDS IN THE SURGICAL MANAGEMENT OF PROXIMAL HUMERUS FRACTURE OVER THE LAST 20 YEARS
No full textProximal humerus fractures (PHF) are common, accounting for approximately 5% of all fractures. Approximately 30% require surgical intervention which can range from open reduction with internal fixation (ORIF) to shoulder arthroplasty (including hemiarthroplasty, total shoulder arthroplasty, (TSA) or reverse total shoulder arthroplasty (RTSA)). The aim of this study was to assess trends in operative interventions for PHF in an Australian population.Data was retrospectively collected for patients diagnosed with a PHF and requiring surgical intervention between January 2001 and December 2020. Data for patients undergoing ORIF were extracted from the Medicare database, while data for patients receiving arthroplasty for PHF were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).Across the study period, ORIF was the most common surgical procedure for management of PHFs. However, since 2019, RTSA has surpassed ORIF as the most common surgical procedure to treat PHFs, accounting for 51% of operations. While the number of RTSA procedures for PHF has increased, ORIF and shoulder hemiarthroplasty has significantly reduced since 2007 (p < 0.001). TSA has remained uncommon across the follow-up period, accounting for less than 1% of all operations. Patients younger than 65 years were more likely to receive ORIF, while those aged 65 years or greater were more likely to receive hemiarthroplasty or RTSA.While the number of ORIF procedures has increased during the period of interest, it has diminished as a proportion of overall procedure volume. RTSA is becoming increasingly popular, with decreasing utilization of hemiarthroplasty, and TSA for fracture remaining uncommon. These trends provide information that can be used to guide resource allocation and health provision in the future. A comparison to similar data from other nations would be useful
TRENDS IN THE SURGICAL MANAGEMENT OF PROXIMAL HUMERUS FRACTURE OVER THE LAST 20 YEARS
No full textProximal humerus fractures (PHF) are common, accounting for approximately 5% of all fractures. Approximately 30% require surgical intervention which can range from open reduction with internal fixation (ORIF) to shoulder arthroplasty (including hemiarthroplasty, total shoulder arthroplasty, (TSA) or reverse total shoulder arthroplasty (RTSA)). The aim of this study was to assess trends in operative interventions for PHF in an Australian population.Data was retrospectively collected for patients diagnosed with a PHF and requiring surgical intervention between January 2001 and December 2020. Data for patients undergoing ORIF were extracted from the Medicare database, while data for patients receiving arthroplasty for PHF were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).Across the study period, ORIF was the most common surgical procedure for management of PHFs. However, since 2019, RTSA has surpassed ORIF as the most common surgical procedure to treat PHFs, accounting for 51% of operations. While the number of RTSA procedures for PHF has increased, ORIF and shoulder hemiarthroplasty has significantly reduced since 2007 (p < 0.001). TSA has remained uncommon across the follow-up period, accounting for less than 1% of all operations. Patients younger than 65 years were more likely to receive ORIF, while those aged 65 years or greater were more likely to receive hemiarthroplasty or RTSA.While the number of ORIF procedures has increased during the period of interest, it has diminished as a proportion of overall procedure volume. RTSA is becoming increasingly popular, with decreasing utilization of hemiarthroplasty, and TSA for fracture remaining uncommon. These trends provide information that can be used to guide resource allocation and health provision in the future. A comparison to similar data from other nations would be useful
