Biomedical subjects

A A Zaghloul

Publications and source records attributed to A A Zaghloul.

10 recordsLinked to original sources

PubMed2006

beta-Estradiol biodegradable microspheres: effect of formulation parameters on encapsulation efficiency and in vitro release.

The purpose of this work was to study the effect of organic solvent and surfactant type on the in vitro release behavior in general and on the burst release in particular of beta-estradiol from PLA/PLGA microspheres. Also the effect of these variables on the encapsulation efficiency was investigated. The microspheres were prepared by solvent evaporation technique using dichloromethane (DCM), ethyl acetate (EtAc), tetrahydrofuran (THF), chloroform (CHCl3) or acetone (AC) as organic solvent and polyvinyl alcohol (PVA), Tween 80, sodium lauryl sulfate (SLS) or benzalkonium chloride (BKCI) as surfactant. The obtained microspheres were tested for encapsulation efficiency and in vitro drug release using 50% methanol/buffer pH 7.4 as dissolution medium. EtAC and PVA formulations showed the highest encapsulation efficiency and the lowest burst release. These microspheres were further characterized for particle size distribution, SEM and zeta potential. The results suggested that these materials could be starting materials to prepare a beta-estradiol biodegradable controlled delivery system.

Biotransformation↗

PubMed2005

The adsorption of Cu(II) ions on bentonite--a kinetic study.

The kinetics of sorption of Cu(2+) on a Saudi clay mineral (bentonite) was investigated at 20+/-0.5 degrees C using different weights of the clay (0.5, 1.0, 1.5, and 2 g). Each weight represents a certain sample size. The order of the process appeared to be 1 with respect to the Cu(2+), and 112 with respect to the clay surface area. The rate was found to depend on internal diffusion.,which produced a decrease in the specific rate of sorption as a function of time. Sorption characteristics were described using two site Langmuir isotherms. The desorption experiments proved that Cu(2+) ions are chemisorbed on the bentonite surface. The maximum adsorption obtained was 909 mg Cu(2+)/g clay. This value is of great significance, as it is much higher than any reported one.

Adsorption↗

PubMed2004

Bioavailability assessment of salbutamol sulfate suppositories in human volunteers.

The purpose of this investigation was to evaluate the bioavailability of three salbutamol sulfate suppository formulations. The formulations were; 2 mg salbutamol sulfate in Suppocire NA base containing 6% Eudispert gel (F1), 2mg salbutamol sulfate in Witepsol H15 base containing 3% methyl cellulose gel (F2), and 2 mg salbutamol sulfate in Witepsol W25 base containing 3% methyl cellulose gel (F3). The formulations were administered via rectal route in six healthy male adult volunteers. The bioavailability of the three suppository formulations was compared with the oral bioavailability of salbutamol sulfate 2mg tablets (F4). Six volunteers participated in a four-way crossover study, where each study was separated from the other by an interval of 1 weak. Venous blood samples of 5 ml were taken immediately before dosing and after predetermined time intervals of 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6 and 8 h. The result showed that Cmax +/- S.D. observed were 12.96 +/- 2.11, 14.78 +/- 2.33, 10.02 +/- 1.42 and 11.51 +/- 1.22 ng ml(-1) for F1, F2, F3 and F4, respectively. The Tmax +/- S.D. were found to be 1.91 +/- 0.20, 1.83 +/- 0.26, 2.50 +/- 0.00 and 2.67 +/- 0.24 h for F1, F2, F3 and F4, respectively. AUC +/- S.D. values were 40.25 +/- 1.88, 42.16 +/- 1.55, 28.62 +/- 1.98 and 37.63 +/- 1.44 ng h per ml for F1, F2, F3 and F4, respectively. The relative bioavailabilities of the investigated formulations were 112.04, 106.96 and 76.06 for formula F2, F1 and F3, respectively, when compared with the oral preparation (F4). The finding indicates that the bioavailability of salbutamol sulfate can be enhanced by delivering it rectally with Suppocire NA base containing 6% Eudispert gel or with Witepsol W25 base containing 3% methyl cellulose to match that of oral tablets. Salbutamol sulfate can be rectally administered in patients who are less compliant with the oral administration.

Adult↗

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↗

PubMed2001

Naproxen-Eudragit microspheres: screening of process and formulation variables for the preparation of extended release tablets.

The objectives of the present study were to screen the formulation and process variables for the preparation of extended release naproxen tablets with Eudragit L100-55. The tablets were prepared by compression of microspheres that were obtained by a coprecipitation technique. The process involved dissolution of naproxen and Eudragit L 100-55 in alcohol USP followed by the addition of an aqueous solution containing a surfactant and deaggregating agents. The mixture was stirred for a specified time period to obtain microspheres, which were filtered and air-dried to a constant weight. The microspheres were then compressed to obtain plain tablets with a diameter of 12 mm. A 7-factor 12-run Plackett-Burman screening design was employed to evaluate the main effects of homogenization time (X1), rate of water addition (X2), amount of polymer (X3), amount of precipitating solution (X4), concentration of electrolytes (X5), compression pressure (X6), and the concentration of lubricant (X7) on the rate of drug release. The response variable was cumulative percent of naproxen dissolved in 12 h in simulated intestinal fluid with constraints on responses that included percent yield, hardness, thickness, and the angle of repose. Mathematical relationship for percent of naproxen dissolved in 12 h (Y5) with various factors yielded the following polynomial equation; Y5 (% dissolved in 12 h) = 95.48 + 0.53 X1 + 3.51 X2 + 3.84 X3 - 3.80 X4 - 2.46 X5 - 2.90 X6 - 3.91 X7. The results showed that all the seven factors affected, with varying order, the release of naproxen from its compressed tablets.

Acrylic Resins↗

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↗

PubMed2001

Honey, a prospective antibiotic: extraction, formulation, and stability.

Old and recent reports show that honey has beneficial effects on the skin as antiseptic for wounds, burns and ulcers and as a healing promoter. Many investigators confirmed the usefulness of honey in the treatment of skin infections as well as internal diseases. The factors behind these effects are not completely explained. The aim of this study is: a) to investigate the antimicrobial activity of crude honey, b) to separate the fractions responsible for its activity, c) to formulate the honey extract as semisolid dosage forms, d) to study its release, and e) to determine its stability. The results showed that the ethylacetate honey extract showed antibacterial, anticandida and antifungal effects at low concentration. The release of honey extract from different ointment bases was depending on the constituents of the base, and its stability was found to be temperature and base dependent.

Acetates↗

PubMed2001

Validation of a patient satisfaction scale for primary care settings.

The objective of this study was to develop and validate an instrument pertinent for the Egyptian culture and situation suitable for use by health centres' administrators as a complementary tool for assessing the quality of outcome of care rendered. The study describes an attempt to develop and validate an instrument of patient satisfaction with primary health settings in Alexandria. A systematic randomized sample (227) of patients attending the outpatient clinics at 4 primary health centres in Alexandria were included in the study. The instrument included a section for respondents' characteristics, and the other section was a 5-point Likert-type scale ranging from highly satisfied (5) to highly dissatisfied (1) was developed by adapting items from other measures of patient satisfaction in the literature. The internal consistency of the instrument was determined, and the Cronbach's alpha coefficient for all scales was 0.80. Using the principal components factor analysis factor loadings for the scale items were high on seven factors. The factors were named technical care, accessibility, structure, humaneness, respect, in return for cost, and the waiting time. The study supports that the instrument is a reliable and valid measure for patient satisfaction suitable for Egyptian primary health settings.

Adult↗

PubMed2000

Chirality and its implications in transdermal drug development.

Today more than 50% of marketed drugs are chiral. It has been well recognized that the stereochemistry of chiral drugs has a major influence on their pharmacological, pharmacokinetic, and toxicological actions. Studies on enantiomeric differences in the percutaneous permeation of chiral compounds have been actively pursued in recent years. Stratum corneum, the rate-limiting barrier in transdermal permeation, is made up of keratin and ceramide, which could potentially provide chiral environment. Transdermal delivery is often facilitated by the presence of penetration enhancers, which act primarily by altering the diffusion by disrupting the highly ordered membrane structure or by affecting the partitioning behavior of the diffusant molecules. Enantioselective permeation was observed with some chiral excipients including terpene enhancers. While studies on crystalline structures of pure enantiomers and racemates are helpful in understanding the basis for differentiation of physicochemical properties, prediction and control of permeability of enantiomers and racemates based on the physicochemical characteristics would be highly beneficial. The flux characteristics of enantiomers and racemates appear to be dependent upon their thermodynamic properties. Such analyses have a predictive value and are useful in the transdermal drug product development of chiral molecules. While the decision to market either an individual enantiomer or racemate lies strictly under the control of the sponsors, the guidance of the Food and Drug Administration is very helpful. This review presents an overview of the skin structure and transport and a concise review of enantioselective permeation with or without chiral enhancers. Regulatory perspectives on chiral drug product development are also discussed.

Administration, Cutaneous↗

PubMedDate not supplied

Response surface methodology to obtain naproxen controlled release tablets from its microspheres with Eudragit L100-55.

PURPOSE: Naproxen CR tablets have been obtained from its microspheres prepared by coprecipitation with Eudragit L100-55. The purpose of this work was to evaluate the main and interaction effects of deaggregating agent concentration (X1), compression pressure (X2) and amount of precipitating water (X3) on naproxen release. A secondary purpose was to obtain an optimized naproxen controlled release solid oral dosage form with a predictable 12 h drug release. METHOD: Eudragit L100-55 (10 g) was dissolved in 100 ml of ethyl alcohol, and 30g of naproxen was dispersed in it with stirring. Purified water (100mL, cooled to 4 degrees C) containing calcium chloride as a deaggregating agent was added to an alcoholic solution and homogenized. The mixture was filtered to obtain microspheres. Drug content analysis was performed spectrophotometrically at 332 nm. Tablets were prepared by compressing microspheres containing 500mg of naproxen after adding 1% magnesium stearate. Dissolution was performed by the USP specifications of naproxen tablets. A 3-factor 3-level Box-Behnken design was employed to get 15 experimental runs. The independent variables used were X1, X2 and X3. The dependent variables were dissolution at different time points with constraints on yield value and angle of repose of the microspheres, and hardness and thickness of the tablets. The dissolution constraints were placed such that the naproxen is released for 12 h by Higuchi's square root of time kinetics. RESULTS: The mathematical relationship obtained between X1, X2, X3 and the cumulative per cent of naproxen dissolved in 12 h with various constraints (Y5) was Y5 = 92.39 - 1.13X1 - 4.84X2 - 2.12X3 - 2.26X1X2 - 0.5X1X3 - 0.4X2X3 + 2.4X(1)(2) - 0.4X(2)(2) (R2 = 0.9). The equation shows that X1, X2 and X3 affected the release inversely, and the most significant interaction was between X1 and X2. Y5 has been maximized for optimization of naproxen release. CONCLUSIONS: Controlled release tablets of naproxen with predictable drug release characteristics were obtained by compressing its microspheres with Eudragit L100-55.

Anti-Inflammatory Agents, Non-Steroidal↗