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M Sergent

Publications and source records attributed to M Sergent.

6 recordsLinked to original sources
PubMed2004

Texture optimization of water-in-oil emulsions.

The aim of this research is to demonstrate the effect of variations in certain parameters of the oily phase (OP) in water-in-oil (W/O) emulsions on rheological and texture properties of finished products. The formulated emulsions were selected according to an optimal experimental procedure. The applied variations were nature of the OP, its volume fraction, the hydrophilic-lipophilic balance (HLB) value, and the surfactant proportion. Results are presented for the followed tests carried out on the emulsions: texture analysis, rheology, and particle size analysis. The oils used in the study were sweet almond oil, liquid paraffin, maize oil, cyclomethicone, dimethicone, and wheat germ oil. The resulting data demonstrate a notable influence of the volume fraction oil on hardness, viscosity, adhesiveness, and cohesiveness of W/O emulsions. Emulsion hardness and viscosity increased as the OP percentage increased; this effect being even more pronounced for the vegetable oils. In contrast, emulsion adhesiveness and cohesiveness decreased as the volume fraction oil increased. The HLB value of the surfactant mixture of the emulsion also influenced hardness, adhesiveness, and elasticity, increasing or decreasing as HLB value did.

Drug Compounding↗
PubMed2003

How experimental design can improve the validation process. Studies in pharmaceutical analysis.

A critical discussion about the possibility of improving the method validation process by means of experimental design is presented. The reported multivariate strategies concern the evaluation of the performance parameters robustness and intermediate precision, and the optimisation of bias and repeatability. In particular, accuracy and precision improvement constitutes a special subset of experimental design in which the bias and the relative standard deviation of the assay are optimised. D-optimal design was used in order to plan experiments for this aim. The analytical methods considered were capillary electrophoresis, HPLC, adsorptive stripping voltammetry and differential pulse polarography. All methods were applied to real pharmaceutical analysis problems.

Adsorption↗
PubMed1998

TQI in the Albuquerque Veterans Affairs Medical Center's long-term oxygen therapy program.

BACKGROUND: Long-term oxygen therapy (LTOT) is the only treatment demonstrated to prolong the life of patients with chronic obstructive pulmonary disease. In November 1994, a multidisciplinary total quality improvement (TQI) team composed of the involved hospital services was established to reorganize and improve the LTOT program at the Albuquerque Veterans Affairs Medical Center (AVAMC), Albuquerque. FROM THE OLD TO THE NEW PROCESS: The LTOT team used a process map to analyze the current process and gather information from patients and staff regarding their satisfaction with the program. It then began working on the identified problems and streamlining the LTOT referral process. A respiratory therapy position with the specific responsibility of serving as the home oxygen (O2) coordinator (HOC) was established and filled. The evaluation process was to be initiated by the AVAMC physicians, following which the HOC would perform a newly standardized evaluation that would establish the patient's need for O2 and result in a specific prescription. RESULTS: Quality indicators were selected to monitor changes in the program. Data from chart reviews, the Veterans Affairs National Cost Containment Center, and patient surveys were used to evaluate the indicators. Timeliness of referral to the program before inpatient discharge improved, O2 prescriptions in the new program more frequently addressed activity, and the cost per patient was reduced by 37.1%. Patient satisfaction rates also improved. DISCUSSION: A motivated team with representatives of the services involved was able to analyze and dramatically improve an important but complicated program.

Cost Control↗
PubMedDate not supplied

Image quality study in 3D X-ray angiography: a first approach using the experimental design strategy.

The visual detection of fine structures and the accuracy of the quantitation of geometric and densitometric features, are closely related to the quality of the images available in two-dimensional (2D) and three-dimensional (3D) X-ray angiography. In this context, we propose to analyze all the parameters influencing this accuracy using an experimental design strategy. Preliminary tests of this procedure, applied to 2D and 3D angiographic data obtained from a dedicated phantom, yield encouraging results. We show that the detection of small arteries in a 3D angiogram is more sensitive to the number of projections than to the X-ray dose.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Influence of experimental parameters on the microencapsulation of a photopolymerizable phase.

Conditions of microencapsulation by in situ polycondensation, using melamine-formaldehyde as wall material, are influenced by the chemical nature of the core to encapsulate. In our study concerning the encapsulation of a photopolymerizable phase containing an electrically charged compound, it was necessary to modify the experimental process to obtain capsules of good quality. We used the factorial design method of screening by utilization of an asymmetric matrix, according to the collapsing principle of Addleman. The advantage of this method is that it allows determination of the simultaneous influences of the 11 experimental parameters involved in this preparation. The calculation method can be applied to more than two levels for some of the factors. The continuously varying parameters were altered between two extreme levels, chosen to allow encapsulation. For discontinuous factors, such as the molecular weight of the modifying system or nature of the aminoplast, we used the commercially available compounds, respectively three and four kinds. The results of the obtained capsules were determined by comparing microphotographic pictures. With 16 experiments we found four more factors influencing quality of capsules. We also determined the most favourable levels for the other seven parameters. The results allowed us to find optimal conditions in the experimental field. We obtained capsules of a satisfactory quality for this purpose, using only minimum experimentation.

Chemistry, Pharmaceutical↗