Biomedical subjects

Mohammed A Hammad

Publications and source records attributed to Mohammed A Hammad.

3 recordsLinked to original sources

PubMed2006

Quality by design: understanding the formulation variables of a cyclosporine A self-nanoemulsified drug delivery systems by Box-Behnken design and desirability function.

Quality by design (QBD) refers to the achievement of certain predictable quality with desired and predetermined specifications. A very useful component of the QBD is the understanding of factors and their interaction effects by a desired set of experiments. The present project deals with a case study to understand the effect of formulation variables of nanoemulsified particles of a model drug, cyclosporine A (CyA). A three-factor, three-level design of experiment (DOE) with response surface methodology (RSM) was run to evaluate the main and interaction effect of several independent formulation variables that included amounts of Emulphor El-620 (X(1)), Capmul MCM-C8 (X(2)) and 20% (w/w) CyA in sweet orange oil (X(3)). The dependent variables included nanodroplets size (Y(1)), nanoemulsions turbidity (Y(2)), amounts released after 5 and 10min (Y(3), Y(4)), emulsification rate (Y(5)) and lag time (Y(6)). A desirability function was used to minimize lag time and to maximize the other dependent variables. A mathematical relationship, Y(5)=9.09-0.37X(1)+0.37X(2)-0.45X(3)+0.732X(1)X(2)-0.62X(1)X(3)+0.3X(2)X(3)+0.02X(1)(2)-0.28X(2)(2)+0.471X(3)(2) (r(2)=0.92), was obtained to explain the effect of all factors and their colinearities on the emulsification rate. The optimized nanodroplets were predicted to yield Y(1), Y(2), Y(3), Y(4), Y(5) and Y(6) values of 42.1nm, 50.6NTU, 56.7, 107.2, 9.3%/min and 3.5min, respectively, when X(1), X(2), and X(3) values were 36.4, 70 and 10mg, respectively. A new batch was prepared with these levels of the independent variables to yield Y(1)-Y(6) values that were remarkably close to the predicted values. In conclusion, this investigation demonstrated the potential of QBD in understanding the effect of the formulation variables on the quality of CyA self-nanoemulsified formulations.

Analysis of Variance↗

PubMed2006

Formulation of anastrozole microparticles as biodegradable anticancer drug carriers.

The purpose of this study was to develop poly(d,l-lactic-co-glycolic acid) (PLGA)-based anastrozole microparticles for treatment of breast cancer. An emulsion/extraction method was used to prepare anastrozole sustained-release PLGA-based biodegradable microspheres. Gas chromatography with mass spectroscopy detection was used for the quantitation of the drug throughout the studies. Microparticles were formulated and characterized in terms of encapsulation efficiency, particle size distribution, surface morphology, and drug release profile. Preparative variables such as concentrations of stabilizer, drug-polymer ratio, polymer viscosity, stirring rate, and ratio of internal to external phases were found to be important factors for the preparation of anastrozole-loaded PLGA microparticles. Fourier transform infrared with attenuated total reflectance (FTIR-ATR) analysis and differential scanning calorimetry (DSC) were employed to determine any interactions between drug and polymer. An attempt was made to fit the data to various dissolution kinetics models for multiparticulate systems, including the zero order, first order, square root of time kinetics, and biphasic models. The FTIR-ATR studies revealed no chemical interaction between the drug and the polymer. DSC results indicated that the anastrozole trapped in the microspheres existed in an amorphous or disordered-crystalline status in the polymer matrix. The highest correlation coefficients were obtained for the Higuchi model, suggesting a diffusion mechanism for the drug release. The results demonstrated that anastrozole microparticles with PLGA could be an alternative delivery method for the long-term treatment of breast cancer.

Anastrozole↗

PubMed2006

Formulation and optimization of mouth dissolve tablets containing rofecoxib solid dispersion.

The purpose of the present investigation was to increase the solubility and dissolution rate of rofecoxib by the preparation of its solid dispersion with polyvinyl pyrrolidone K30 (PVP K30) using solvent evaporation method. Drug-polymer interactions were investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). For the preparation of rofecoxib mouth dissolve tablets, its 1:9 solid dispersion with PVP K30 was used with various disintegrants and sublimable materials. In an attempt to construct a statistical model for the prediction of disintegration time and percentage friability, a 3(2) randomized full and reduced factorial design was used to optimize the influence of the amounts of superdisintegrant and subliming agent. The obtained results showed that dispersion of the drug in the polymer considerably enhanced the dissolution rate. The drug-to-carrier ratio was the controlling factor for dissolution improvement. FTIR spectra revealed no chemical incompatibility between the drug and PVP K30. As indicated from XRD and DSC data, rofecoxib was in the amorphous form, which explains the better dissolution rate of the drug from its solid dispersions. Concerning the optimization study, the multiple regression analysis revealed that an optimum concentration of camphor and a higher percentage of crospovidone are required for obtaining rapidly disintegrating tablets. In conclusion, this investigation demonstrated the potential of experimental design in understanding the effect of the formulation variables on the quality of mouth dissolve tablets containing solid dispersion of a hydrophobic drug.

Absorption↗