Magda Sokar

Preparation and evaluation of ketoprofen floating oral delivery system

A sustained release system for ketoprofen designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microparticles by the emulsion-solvent diffusion technique. Four different ratios of Eudragit S100 (ES) with Eudragit RL (ERL) were used to form the floating microparticles. The drug retained in the floating microparticles decreased with increase in ERL content. All floating microparticle formulations showed good flow properties and packability. Scanning electron microscopy and particle size analysis revealed differences between the formulations as to their appearance and size distribution. X-ray and DSC examination showed the amorphous nature of the drug. Release rates were generally low in 0.1 N HCl especially in presence of high content of ES while in phosphate buffer pH 6.8, high amounts of ES tended to give a higher release rate. Floating ability in 0.1 N HCl, 0.1 N HCl containing 0.02% Tween 20 and simulated gastric fluid without pepsin was also tested. The formulation containing ES:ERL1:1 (FIII) exhibited high percentage of floating particles in all examined media.

Chitosan and sodium alginate—Based bioadhesive vaginal tablets

Metronidazole was formulated in mucoadhesive vaginal tablets by directly compressing the natural cationic polymer chitosan, loosely cross-linked with glutaraldehyde, together with sodium alginate with or ine cellulose (MCC). Sodium carboxymethylcellulose (CMC) was added to some of the formulations. The drug content in tablets was 20%. Drug dissolution rate studies from tablets were carried out in buffer pH 4.8 and distilled water. Swelling indices and adhesion forces were also measured for all formulations. The formula (FIII) containing 6% chitosan, 24% sodium alginate, 30% sodium CMC, and 20% MCC showed adequate release properties in both media and gave lower values of swelling index compared with the other examined formulations. FIII also proved to have good adhesion properties with minimum applied weights. Moreover, its release properties (% dissolution efficiency, DE) in buffer pH 4.8, as well as release mechanism (n values), were negligibly affected by aging. Thus, this formula may be considered a good candidate for vaginal mucoadhesive dosage forms.

Mucopenetrating nanoparticles for enhancement of oral bioavailability of furosemide: In vitro and in vivo evaluation/sub-acute toxicity study

The aim of this study was to formulate and evaluate chitosan (CS)/alginate (ALG) nanoparticles (NPs) loaded with furosemide (FSM) in an attempt to enhance its release, permeability and bioavailability. Non-everted gut sac method was used to evaluate the ex vivo permeation of FSM from its suspension and the selected CS/ALG NPs formulation. The pharmacokinetic parameters of FSM subsequent to oral administration of the selected formulation were assessed in rats. In vivo subacute toxicity study of the prepared blank and FSM loaded formulations was evaluated in rats. The selected optimized formulation (F3) showed optimum particle size (PS), polydispersity index (PDI), zeta potential (ZP) and acceptable percentage entrapment efficiency (%EE) of 253.8nm±4.6, 0.25±0.03, -35mV±1 and 96%±1, respectively. The release profile of FSM from the selected formulation was characterized by initial burst effect in 0.1N HCl. Scanning electron microscope (SEM) demonstrated a smooth surface and spherical shape for the lyophilized optimized NPs. Selected CS/ALG NPs (F3) presented a significant enhancement (p≤0.01) in permeation parameters of FSM as well as in Tmax, Cmax, AUC0-24 and AUC0-∞. Subacute toxicity study results revealed that the selected formulation was safe and nontoxic. The histopathological inspection of the stomach and small intestine tissues of the loaded NPs (F3) and blank groups reflected no obvious signs of cellular toxicity or inflammatory reaction. CS/ALG NPs loaded with FSM enhanced both drug release and mucus-penetrating ability leading to an overall increase in FSM bioavailability. In addition, the in vivo subacute toxicity study results indicated the safety of the prepared NPs for oral drug delivery.

Design of Chronomodulated Drug Delivery System of Valsartan: In Vitro Characterization.

The aim of the present study was to design and evaluate a chronomodulated time-clock pulsatile tablets of valsartan to release it after a certain lag time, independent of the gastrointestinal pH, in its absorption window to cope with the circadian rhythm of human body for blood pressure elevation. Core tablets were prepared by direct compression of a homogenous mixture of valsartan, Avicel PH101, croscarmellose sodium, magnesium stearate and Aerosil. The core tablets were then sprayed coated with a sealing layer formed of ethyl cellulose that was subsequently coated with a release-controlling layer. Three different aqueous dispersions namely; carnauba wax or beeswax or a mixture in a ratio of 2.5:1, respectively, were used to form five time-clock tablet formulations having the release controlling layer with different thickness {B5, B10, B20, BW5 and CW5}. Quality control testing were carried out to the core tablets. Differential scanning calorimetry was also performed to detect the possible drug excipient interaction in the core tablet formulation. The release was carried out, for the prepared time-clock tablet formulations, in 0.1 N hydrochloric acid for the first 2 h, followed by phosphate buffer (pH 6.8) for 4.5 h. The effect of pH on valsartan release was studied through a release study in 0.1 N hydrochloric acid for 6.5 h. Two phase dissolution study was performed to the selected time-clock tablet formulation to predict the drug permeation through the gastrointestinal tract. Stability study of the selected formula was performed at 25°/60% RH and at 40°/75% RH for 3 months. Results showed that a release-controlling layer composed of a mixture of carnauba wax and beeswax in a ratio of 2.5:1 showed a reasonable release lag time. The release lag time of the tablets increased with the increase of the coat thickness, thus B20>B10>B5 with corresponding lag time values of 4.5, 3 and 2.5 h, respectively. Selected B5 tablet formula exhibited a reasonable lag time after which the highest, complete % drug release at pH 6.8 was obtained. In addition, a good partitioning of valsartan, between the aqueous and organic phases in a ratio of 1:7, was observed. The selected formula was stable for at least 3 months under standard long-term and accelerated storage conditions. In conclusion, in vitro studies revealed that the novel time-clock system could be used successfully to deliver valsartan in a pulsatile pH-independent manner. It provided a desirable lag time followed by a rapid and complete drug release accompanied by an expected effective permeation through the biological membranes upon release in the duodenum; the window of absorption, as indicated by the two phase release study.

A dual strategy to improve psychotic patients’ compliance using sustained release quetiapine oral disintegrating tablets

Abstract Quetiapine (QT) is a short acting atypical antipsychotic drug effective in schizophrenia and bipolar disorder. This study aims at designing a novel dosage form of sustained release taste-masked QT orally disintegrating tablets (ODTs) based on solid lipid micro-pellets (SLMPs). QT SLMPs were prepared using the hot melt extrusion technique and utilizing three lipid carriers: Compritol, Precirol and white beeswax either alone or in mixtures. They showed sustained QT release and a taste masking effect. The selected QT SLMP was further blended with an aqueous solution containing polyvinylpyrollidone (2.5 %), croscarmellose sodium (2 %) and mannitol (50 %); it was then lyophilized into ODT in a mass ratio of 1:2, respectively. ODTs containing QT SLMPs showed: average wetting time (40.92 s), average oral disintegration time (21.49 s), average hardness (16.85 N) and also imparted suitable viscosity to suspend pellets during the lyophilization process. In conclusion, lyophilization is a promising technique for the formulation of multiparticulate systems into ODTs.

Valsartan time-clock pulsatile tablet formulations preparation and in vitro evaluation

W an objective to assess the perception of community pharmacists towards the quality and prices of locally manufactured medicine in Kabul, Afghanistan a cross-sectional study was conducted. A total of n=198 community pharmacists was approached in Kabul city to participate in the survey. Most of the pharmacists n=140 (70.7%), had 11-20 years of pharmacy practice in the community. As Afghanistan’s pharmaceutical sector depends on imported medicines, we found that, n=91 (45.90%) pharmacists chose Abbot, GSK and Getz (Pakistani pharmaceutical company), n=46 (23.2%) pharmacists chose Exir (Iranian pharmaceutical company) to obtain their medicine and, n=31 (15.7%) of pharmacists chose to obtain locally manufactured medicines. When the community pharmacists asked, that locally manufactured generics are equal in their quality compared to the imported generics, about 50.50% of the respondents have shown their disagreement and, 50% have shown their agreement. Results depict that 70.70% of the respondents believed that manufacturers of local generic products have a reliable logistic and drug delivery system and 50% of the respondents preferred to stock and dispense locally manufactured generics because the companies provide a good bonus scheme. Importantly, 80.8 % of the respondents believed that credibility is their concern when stocking medicines in their pharmacy and warehouses. Majority 90.40% of the respondents suggested that the Afghan government need to convince pharmacists that registered locally manufactured generics are of high quality and standards.