Hamed H. El-Shattawy

Aspartame-Direct Compression Excipients: Preformulation Stability Screening Using Differential Scanning Calorimetry

AbstractDifferential scanning calorimetry was used as a screening technique for assessing the compatibility of Aspartame with some of the currently available direct compression excipients. AsDartame was found to be compatible with Avicel PH 101, Avicel PH 105, Elcema F 150, Elcema G 250, Sta-Rx 1500, Cab-O-Sil, Sorbitol, Di-Pac and Brownex Sugar, while incompatible with dicalcium phosphate dihydrate. It appears that stearic acid can be used as a lubricant in formulations containing Aspartame while magnesium stearate cannot.

Aspartame-Mannitol Resolidified Fused Mixture: Characterization Studies by Differential Scanning Calorimetry, Thermomicroscopy, Photomicrography and X-Ray Diffractometry

AbstractDifferential scanning calorimetry, thermomicroscopy, photomicrography and X-ray diffractometry were used to characterize the physical nature of the resolidified ten percent aspartame-mannitol fused mixture. It is concluded that the binary system is a eutectic mixture with some solid-solid solubility. The increased hardness of the eutectic is regarded as an advantage for the mixture as a base for chewable tablets.

Differential Scanning Calorimetry of Aspartame-Mannitol Mixture

AbstractDifferential scanning calorimetry was used to study both the qualitative and quantitative thermal properties of mixtures of aspartame with both mannitol and granular mannitol. Aspartame was found to be compatible with both forms of mannitol. No aspartame decomposition was observed in the preparation of a fused aspartame-mannitol mixture prepared at 161-165°C. L-(-)-leucine can be recommended as soluble lubricant for formulations containing aspartame and mannitol.

Controlled-Release Frusemide Microcapsules: Preformulation Studies

AbstractMicroencapsulation of plain frusemide or its solid-dispersion with PEG 6000 was achieved by phase-separation coacervation. Formulations showed reasonable in-vitro dissolution behaviour were assessed for their absorption rates by LD50 testing in mice. Toxicity studies showed close agreement between the increase in lethal dose and the decrease in dissolution rate and revealed that the formulation containing frusemide as fused mixture with PEG 6000 and microencapsulated with polystyrene, in frusemide-PEG 6000-polystyrene weight ratio of 2:2:1, was the formula of choice for prolonging the absorption, hence, the action of frusemide.

Differential Scanning Calorimetry of Aspartame-Caffeine Mixture

The possible interaction between aspartame and caffeine was investigated by comparing the thermal behavior, using differential scanning calorimetry, of physical mixtures of aspartame and caffeine along with mixtures, in the same molar ratios, obtained as the co-precipitate. Caffeine was found to form several complexes with aspartame. These complexes were found to be dependent on the molar ratios of aspartame to caffeine. The stoichiometry of the aspartame-caffeine complexes were determined from the enthalpy change of the DSC transitions resulting from the complex formation.

Differential Scanning Calorimetry of Ampicillin-Aspartame Mixture

AbstractThe possible interaction of anhydrous and trihydrate ampicillin with aspartame, in the solid state, was investigated by comparing the thermal behavior of physical mixtures of the respective original components in different molar ratios, using differential scanning calorimetry. Aspartame was found to form complexes with anhydrous ampicillin and ampicillin trihydrate. These complexes were found to be dependent on the molar ratios of the mixture components. One of the complexes between anhydrous and trihydrate ampicillin and aspartame, as determined from the enthalpy change of the DSC transitions of the mixtures, was found to have a 2:1 molar ratio.

Phenylpropanolamine HCl Microcapsules: Preparation and release studies

AbstractMicrocapsules of phenylpropanolamine HCL were prepared by three techniques, viz. coacervation-phase separation, air suspension, and pan coating, using different polymers and/or waxes as wall-forming materials.Formulations showed reasonable dissolution behaviour, viz. microcapsules prepared by air suspension with polymer level of 20% polyvinyl acetate copolymer (PVAC) associated with 40% carnauba wax (II) and microcapsules prepared by pan coating with polymer level of 25% RodopaceR (III), were evaluated for their absorption rates by demonstrating their toxicities compared to pure grug (I) by the LD50 method. Toxicity assessment showed close agreement between the increase in lethal dose and the decrease in dissolution rate and revealed that Formula III has more prolonged action than Formulae II and I.

Preparation and Evaluation of Directly-Compressed Indomethacin, Indomethacin Sodium and Indomethacin Meglumine Tablets

AbstractA formula containing Compactrol, Ac-Di-Sol, Aerosil 200 and talc was used to prepare directly-compressed tablets of indomethacin and its sodium and meglumine salts. The prepared tablets were evaluated for uniformity of weight and thickness, hardness, friability and content uniformity. Each batch was then divided into two, one was coated with an opaque non-enteric film coat and evaluated for coat thickness uniformity. The dissolution rates of the uncoated and coated tablets and the effect of shelf-storage, at room temperature for 11 months, on drug contents were also studied. Indomethacin meglumine tablets showed the least relative standard deviation of weight and thickness. They exhibited acceptable uniformity of content and coat thickness, and the highest hardness-friability ratio. Also exhibited, uncoated and coated, the best in-vitro release of its drug contents and the maximal stability.

Micromixing of Oral Contraceptives

AbstractThe role of the mixing process and the influence of the different processing steps on the homogenous distribution and accurate dosage of small amounts of norethisterone acetate and ethinyl estradiol, as models of classical type contraceptives, was studied.The multistage mixing technique of 1 part norethisterone acetate and 1 part ethinyl estradiol in 55 and 1100 parts respectively of tablet filling material using a Lodige-mixer (type F.M. 130D.) showed a reasonable degree of homogenity after 2400 revolutions of the final mixing step. Wet granulation, mixing with the external phase, and compression developed partial segregation in the system which was within tolerable limits.Statistical treatment of the results indicated that the maximum deviation developed through mixing, granulation, mixing with the external phase, compression, sampling and analysis was within ± 5% for norethisterone acetate and ± 10% for ethinyl estradiol. Therefore, the critical tolerance limits specified for a sample of 20 tab...

Release Studies of Neomycin From Different Ophthalmic Ointment Bases

AbstractThe release of neomycin from ten different ointment bases for possible ophthalmic use was monitored using a microbiological agar plate method. An obvious difference in antibiotic release from the various bases was observed. The effect of benzalkonium chloride, as preservative, on the antimicrobial activity of neomycin was studied and found to be dependent on the base used. From the whole set of results for release and stability, after shelf storage for 24 months, Bases No. 9 (containing castor oil, hydrogenated castor oil and cetyl alcohol) and No. 10 (containing liquid paraffin, hard paraffin, glyceryl monostearate and wool fat) were found to be the bases of choice for neomycin ophthalmic ointments.