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S Nazzal

Publications and source records attributed to S Nazzal.

9 recordsLinked to original sources
PubMed2002

Optimization of a self-nanoemulsified tablet dosage form of Ubiquinone using response surface methodology: effect of formulation ingredients.

The objectives of the present study were (1) to evaluate the effect of formulation ingredients on the release rate of Ubiquinone from its adsorbing solid compact; and (2) to prepare and evaluate an optimized self-nanoemulsified tablet formulation. A three factor, three-level Box-Behnken design was used for the optimization procedure, with the amounts of copolyvidone (X(1)), maltodextrin (X(2)) and microcrystalline cellulose (X(3)) as the independent variables. The response variable was cumulative percent of Ubiquinone emulsified in 45 min with constraints on weight, flowability index, tensile strength, friability and disintegration time of the dry powdered emulsion and the resultant compact. Based on the experimental design, different Ubiquinone release rates and profiles were obtained. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The regression equation generated for the cumulative percent emulsified in 45 min was Y(6)=64.10-12.32X(1)-4.36X(2)-25.53X(3)+6.99X(1)X(2)+3.97X(1)X(3)+9.70X(2)X(3)-8.98X(1)(2)16.22X(2)(2)+17.10X(3)(2). The optimization model predicted an 85.4% release with X(1), X(2) and X(3) levels of 66.6, 560.1 and 100, respectively. A new formulation was prepared according to these levels. The observed responses were in close agreement with the predicted values of the optimized formulation.

Cellulose↗
PubMed2002

Preparation and in vitro characterization of a eutectic based semisolid self-nanoemulsified drug delivery system (SNEDDS) of ubiquinone: mechanism and progress of emulsion formation.

The objectives of the present work were, first, to develop a self-nanoemulsified drug delivery system (SNEDDS) based on the eutectic properties of ubiquinone (CoQ10); and second, to study the progress of emulsion formation and drug release mechanisms by turbidimetry and droplet size analysis. Binary phase diagrams of CoQ10 with menthol and essential oils were constructed and used to develop the self-nanoemulsified formulation. Pseudo ternary phase diagram was constructed to identify the efficient self-emulsification region. Release mechanisms of the resultant formulas were quantified using turbidimetry in combination with dissolution studies. Turbidity time profiles revealed three distinctive regions: lag phase, plateau, and the pseudolinear phase. Lag phase was attributed to the liquid crystalline properties of the formula. Plateau turbidity was correlated with droplet size. Laser diffraction analysis revealed an average droplet diameter of 100 nm. Emulsification rate was obtained from the corrected slope of the pseudolinear phase of the profile. Stability of the formula was further evaluated using Fourier transform-infrared (FT-IR) attached to an attenuated total reflectance (ATR) accessory. The present study revealed a eutectic based semisolid self-emulsified delivery system that can overcome the drawbacks of the traditional emulsified systems such as low solubility and irreversible precipitation of the active drug in the vehicle with time.

Calorimetry, Differential Scanning↗
PubMed2001

Characterization of soft gelatin capsules by thermal analysis.

Thermal analysis of soft gelatin capsule was used as a diagnostic tool to evaluate the effect of temperature and humidity stress conditions as well as formulation water, propylene glycol and ethanol on the softening of the gelatin shells. Results obtained using modulated and conventional DSC given as DeltaT(m) (change in gel-sol transition temperature) were compared with the results obtained using manual hardness tester given as % hardness loss. No difference between the two methods was observed in their ability to determine the extent of softening due to formulation water, propylene glycol and ethanol content. Thermal analysis and shifts in the reversible heat flow determined using MDSC provided additional insight into the structural changes and extent of deformation within the gelatin network upon exposure to formulation ingredients, temperature and humidity. Modulated thermal analysis is, therefore, a useful tool for screening the variables influencing the hardness of gelatin capsules.

Calorimetry, Differential Scanning↗
PubMed2001

Transport studies of insulin across rat jejunum in the presence of chicken and duck ovomucoids.

Our aim was to evaluate the transport of insulin across rat jejunum in the presence of ovomucoids and to assess the effect of ovomucoids on intestinal tissue by studying the permeation of a lipophilic and a hydrophilic marker. Rat jejunal segments were mounted in a side-by-side diffusion chamber filled with Krebs bicarbonate buffer, bubbled with 95% O2/5% CO2 at a fixed flow rate and maintained at 37 degrees C. The permeation of insulin, a lipophilic marker ([7- 3H] testosterone) and a hydrophilic marker (D-[1- 14C] mannitol) was evaluated in the presence of 0.5-1.5 microM duck ovomucoid (DkOVM) or chicken ovomucoid (CkOVM). For stability and permeation of insulin in the presence of alpha-chymotrypsin, an enzyme-to-inhibitor ratio of 1:1 and 1:2 was used. In the absence of alpha-chymotrypsin, the permeability coefficient (Papp) of insulin at pH 7.4 was 0.922+/- 0.168 x 10(-7) cm s(-1), which decreased with increasing concentrations of DkOVM or CkOVM. Conversely, the permeation of the hydrophilic and lipophilic marker increased with increasing concentrations of CkOVM and DkOVM. In stability studies, the percentage of drug remaining was found to be 2-fold higher at the 1:2 ratio than with the 1:1 ratio of enzyme to inhibitor. This was in agreement with the 2-fold increase in flux values of insulin in the presence of alpha-chymotrypsin and DkOVM at the 1:2 ratio of enzyme to inhibitor. The decrease in permeation of insulin in ovomucoids was unexpected. Marker transport studies indicated that ovomucoids have the potential to modulate transcellular and paracellular permeability. The flux enhancement of insulin in the presence of alpha-chymotrypsin and DkOVM is encouraging. The use of ovomucoids offers potential to enhance oral delivery of insulin and warrants further investigation.

Animals↗
PubMed2001

Analysis of ubidecarenone (CoQ10) aqueous samples using reversed phase liquid chromatography.

A novel method was developed for the quantitative determination of ubidecarenone (CoQ10) in aqueous media using non aqueous reversed phase liquid chromatography. Standards were prepared by melting the compound in Cremophor EL followed by dilution with distilled water. Samples were then analyzed by a Reverse Phase HPLC method using a Waters Novapak C18, 3.9 x 150 mm column. The mobile phase used was methanol: n-hexane (9:1) at a flow rate of 1.5 ml/min. Response of the detector to the analyte was linear (r: 0.999) over the range of 2.5-100 micrograms ml-1, with a limit of detection of 0.17 microgram ml-1. Acetone used to solubilize CoQ10 in the surfactant and Cremophor EL did not interfere with sample analysis. This method provided a convenient and alternative approach to the existing methods that require organic solvent extractions prior to analysis. Besides, this method enabled the separation of major photolytic decomposition products of CoQ10.

Chromatography, High Pressure Liquid↗
PubMed2000

Captopril gastrointestinal therapeutic system coated with cellulose acetate pseudolatex: evaluation of main effects of several formulation variables.

Maintenance of constant drug levels in the body for those drugs that are used in management of hypertension is extremely beneficial. This can be successfully achieved by delivering the antihypertensives as osmotically-controlled drug-delivery system that essentially eliminates the influence of pH on the drug release. The main objective of this study was to evaluate the main effects of the formulation variables on the release of captopril from osmotically-controlled drug-delivery system coated with a custom-made cellulose acetate (CA) pseudolatex reported earlier. A secondary objective was to identify a suitable antioxidant for incorporating in the formulation as the drug undergoes metal-catalyzed oxidative degradation. The drug showed good stability (> or = 90% intact captopril) in solution in the presence of ascorbic acid for a period of 48 h. A seven-factor, 12-run Plackett-Burman screening design was employed to study the main effects of amounts of Polyox(R) N10 and N80, Carbopol(R) 934P and 974P, sodium chloride, orifice size, and % coating weight gain. The response variable was cumulative percent of drug released in 12 h, Y(3), with constraints on lag time Y(1) and time for 50% drug released Y(2)amount of sodium chloride (1.97).

Algorithms↗
PubMed2000

Stability characterization of controlled release coprecipitates and solid dispersions.

The present study was conducted to determine the effects of ageing at exaggerated storage conditions on controlled release tablets prepared with indomethacin-Eudragit((R)) coprecipitates (CPs) and solid dispersions (SDs). CPs and SDs compressed as tablets were stored at -20, 4, 37, 45, 55, 37 degrees C/11% RH, 37 degrees C/51% RH and 37 degrees C/91% RH. The samples were analyzed over a period of six months for their dissolution, crystalline reversion and thermal changes. Samples stored at extremely low temperatures, higher temperatures and humidity conditions exhibited a significant decrease in dissolution rates. However, no significant change in the release rates was observed for samples stored at 4 degrees C. The degree of crystallinity increased over a period of time as confirmed by X-ray diffractometry. DSC data demonstrated that indomethacin exists in two polymorphic forms, Form I (mp 160-161 degrees C) and Form II (mp 153-154 degrees C). CPs showed an endotherm of Form I, whereas SDs showed a mixture of Form I and II.

Acrylic Resins↗
PubMed1988

Brucella infective endocarditis. Successful combined medical and surgical therapy.

Five cases of Brucella infective endocarditis are described involving a native aortic valve, two native mitral valves, a mitral valve bioprosthesis, and a ventricular septal defect patch. The diagnosis of Brucella infective endocarditis was established from the clinical features, with a high Brucella serologic titer in each case. Blood and tissue cultures were positive in four of five patients. Two-dimensional echocardiograms demonstrated moderately large vegetations on the three affected native valves and the patch and also revealed the development of vegetation on the mitral bioprosthesis as the disease progressed. All the patients were successfully treated by combined surgical and medical therapy, the latter consisting of co-trimoxazole, tetracycline, and streptomycin/gentamicin for 6 weeks; the affected valves and the ventricular septal defect patch were all replaced. There were no operative deaths and there has been no recurrence of infection to date. One patient died suddenly of an unknown cause 1 year after the operation.

Adult↗