Biomedical subjects

Evone S Ghaly

Publications and source records attributed to Evone S Ghaly.

5 recordsLinked to original sources

PubMed2006

Effect of hydrodynamic environment on tablet dissolution using flow-through dissolution apparatus.

The main objective of this research is to investigate the principles underlying the dissolution process, study the phenomena of drug release in laminar flow, and better understand the effect of hydrodynamic condition on drug dissolution, in order to predict drug dissolution from a solid dosage form. Two drug models were selected, theophylline (Class I) and naproxen (Class II), and were formulated into conventional tablets containing 105 mg theophylline or 300 mg naproxen using wet granulation method. Additionally theophylline (105 mg) and naproxen (300 mg) matrices containing 30% hydroxypropylmethylcellulose (HPMC) polymer were prepared by direct compression and tested for dissolution using both USP II and IV dissolution apparatus. Tablets were tested for dissolution (USP IV) using different cell diameter, flow rate, and different position of the tablet inside the cell. In general, the drug dissolution at a given time is a direct function of the flow rate, increasing the flow rate increases drug release. The use of a small cell resulted in faster drug dissolution and higher Reynold's Number than using a large cell. Tablet position in the cell, also has an effect on drug dissolution, inserting the tablet in a horizontal position inside the cell gave faster dissolution than a vertical position. The hydrodynamic conditions did not affect the drug dissolution from HPMC controlled release tablets indicating that the drug dissolution is controlled by the matrix. An equation to predict drug dissolution from conventional tablets was established: Sh=-21.36+10.58Re(1/2) where R2=0.98. This study demonstrated that hydrodynamic conditions, and type of dissolution testing apparatus used have an effect on dissolution rate, mass transfer rate, and film thickness underlying dissolution process.

Solubility↗

PubMed2005

Prediction of tablets disintegration times using near-infrared diffuse reflectance spectroscopy as a nondestructive method.

The goals of this study are to user near-infrared reflectance (NIR) spectroscopy to measure the disintegration time of a series of tablets compacted at different compressional forces, calibrate NIR data vs. laboratory equipment data, develop a model equation, validate the model, and test the model's predictive ability. Seven theophylline tablet formulations of the same composition but with different disintegration time values (0.224, 1.141, 2.797, 5.492, 9.397, 16.8, and 30.092 min) were prepared along with five placebo tablet formulations with different disintegration times. Laboratory disintegration time was compared to near-infrared diffuse reflectance data. Linear regression, quadratic, cubic, and partial least square techniques were used to determine the relationship between disintegration time and near-infrared spectra. The results demonstrated that an increase in disintegration time produced an increase in near-infrared absorbance. Series of model equations, which depended on the mathematical technique used for regression, were developed from the calibration of disintegration time using laboratory equipment vs. the near-infrared diffuse reflectance for each formulation. The results of NIR disintegration time were similar to laboratory tests. The near-infrared diffuse reflectance spectroscopy method is an alternative nondestructive method for measurement of disintegration time of tablets.

Algorithms↗

PubMed2004

Prediction of drug dissolution from tablets using near-infrared diffuse reflectance spectroscopy as a nondestructive method.

The goal of this study is to use near-infrared (NIR) reflectance spectroscopy to measure the percentage drug dissolution from a series of tablets compacted at different compressional forces, calibrate NIR data vs. laboratory equipment data, develop a model equation, validate the model, and test the model predictive ability. Seven theophylline tablet formulations of the same composition but with different dissolution profiles were prepared. Laboratory dissolution profiles were compared with NIR diffuse reflectance data. Linear regression, quadratic, cubic, and partial least-square techniques were used to determine the relationship between dissolution profiles data and NIR spectra. The results demonstrated that a decrease in the amount of drug dissolution produced an increase in NIR absorbance. A series of model equations, depending on the mathematical technique used for regression, were developed from the calibration of the percentage of drug dissolution by using laboratory equipment vs. the NIR diffuse reflectance for each formulation. The results of NIR dissolution data were similar to laboratory tests. The NIR diffuse reflectance spectroscopy method is an alternative, nondestructive method for measurement of drug dissolution from tablets.

Algorithms↗

PubMed2003

Prediction of tablet hardness and porosity using near-infrared diffuse reflectance spectroscopy as a nondestructive method.

The main objective of this research is to use the near-infrared diffuse reflectance method to evaluate and quantify the effects of hardness and porosity on the near-infrared spectras of tablets. To develop a model equation, validate the model and test the model predictive ability. Seven theophylline tablet formulations of the same composition but with seven different hardness values (3, 6, 8, 10, 12, 15, and 17 kp) were prepared. Another seven theophylline tablets formulation with seven different porosity values (57.4, 50.3, 41.9, 40.3, 39.9, 37.3, and 35.1%) were prepared. Five placebo tablets formulation with different hardness and porosity values were also prepared. Laboratory hardness and porosity values were compared to near-infrared diffuse reflectance data. Linear regression, quadratic, cubic and partial least square techniques were used to determine the relationship between hardness, porosity and the near-infrared spectras. The results demonstrated that an increase in tablet hardness and a decrease in tablets porosity produced an increase in near-infrared absorbance. Series of model equations depending on the mathematical technique used for regression were developed from the calibration of hardness and porosity data using laboratory equipment vs. the near-infrared diffuse reflectance for each formulations. The results of near-infrared hardness and porosity predictions were very similar to laboratory hardness and porosity tests. The near-infrared diffuse reflectance spectroscopy method is an alternative nondestructive method for measurement of hardness and porosity of tablets.

Cellulose↗

PubMed2002

Matrices of water-soluble drug using natural polymer and direct compression method.

The objective of this research was to find an optimum Carrageenan matrix formulation with the desired drug release and physical properties prepared by direct compression. In order to achieve this, matrices containing 10% theophylline, different Carrageenan level, and different excipient were prepared and evaluated. A selected matrix containing 40% Carrageenan and lactose fast flo was tested for dissolution in three different dissolution media (distilled water, 0.1 N HCl, and phosphate buffer pH 7.4). The same formulation was also tested for dissolution at 50 rpm, 100 rpm, and 150 rpm, and using different dissolution apparatus (Apparatus 1 and 2). All matrices showed a decrease in drug release as the polymer level was increased. Only Avicel PH-101 did not show any significant difference between matrices prepared with 30% and 40% polymer. At 10% polymer level, it appears that the type of diluent used controls the drug release. However, at high polymer level, 30% and 40%, it appears that the polymer level controls the drug release. Phosphate buffer pH 7.4 and 0.1 N HCl increase drug release and appear to increase Carrageenan solubility and decrease gel formation. Also, as the rotational speed of the apparatus was increased, the integrity of the gel layer was decreased, and the release of drug was increased. The drug release from Carrageenan matrices appears to follow the diffusion model for inert matrix up to 90 min. After 90 min, the drug release follows a zero-order model. This study demonstrated that matrices using Carrageenan can be successfully prepared by direct compression.

Carrageenan↗