Neil R. Anderson

The Quantitative Evaluation of a Granulation Milling Process II. Effect of Ouput Screen Size, Mill Speed and Impeller Shape

AbstractThe processing variables associated with the comminution of pharmaceutical granulations were investigated. The three variables chosen were mill speed, output screen size and impeller shape. Experiments were performed on an aspirin granulation using proper techniques of experimental design. Analysis showed that the three mill variables cannot be considered independently but rather at the level of combinations. A complete characterization of the mill output according to particle size distribution is then possible based upon these combinations of mill variables.

The Quantitative Evaluation of a Granulation Milling Process III. Prediction of Output Particle Size

AbstractRegression analysis was performed using comminution data from the previously presented Comil®G/aspirin granulation characterization study. Polynomial models were constructed using mill speed, output screen size and impeller shape as independent variables. The models were used to predict the mean particle size (µd) and geometric standard deviation (σd) of particle size distributions resulting from the comminution of aspirin using the Comil®G. The predictions were found to compare well with observed values.

The Use of Restriction Errors in the Design of Experiments

AbstractBy Incorporating restriction errors into experimental design models, the developmental scientist is forced to consider what restrictions on randomization have been placed on his experiment whether they are inadvertent or planned. With the experimental design in mind along with the restriction errors the scientist should be able to eventually establish a very reasonable design model and analysis for that experiment.One of the more fundamental tools of pharmaceutical research and development, particularly in the design of dosage forms, is that of the accelerated stability test (1). In general, accelerated testing done early in the development scheme is designed to screen the formulation for the effects caused by changing variables. Variables are anything associated with the formula or the manufacturing of the formula. Many developmental scientists would change only one variable at a time. While this may be sound advice occasionally, it is time consuming and could actually miss the most important eff...

The Quantitative Evaluation of a Granulation Milling Process I. Algebraic Method for Particle Size Analysis

AbstractA method is presented which may be used to mathematically express particle size distributions of pharmaceutical granulations.The method utilizes expresses of particle size and probability evaluated using a weighted linear regression technique. This method is suggested whenever particle size determinations are used in conjunction with statistical analysis, optimization techniques or any time a purely quantitative approach is needed.