Randa Latif

The aim of the present work was to develop controlled release, gastroretentive device
using superporous hydrogel composite (SPHC). Furosemide was chosen as good
candidate for such system due to its narrow absorption window, low bioavailability
and short half-life. Plain hydrogel was evaluated with respect to swelling ratio,
apparent density and floating time. Scanning electron micrographs of SPHC showed
large interconnected pores and extensive capillary insertion. Prepared Microspheres
were tested for drug content, and tablets evaluated with respect to quality control
tests. All loaded formulae inside SPHC were tested for drug release profile.
Microspheres, tablets and drug solutions were tested for loading inside SPHC. Kinetic
treatment of release data revealed that soaked drug solution was unable to control
drug release, where it gave a t1/2(0.5hrs) very similar to that of the free drug (0.6hrs).
Loaded microspheres showed only a slight retardation in release t1/2 to 1.06 hrs along
with a high percent of flush (~30mg %). However, loaded tablet demonstrated a
promising sustained effect corresponding to a release t1/2= 6hrs and a low percent of
initial flush (~1.2mg %). Therefore, the applicability of SPHC as a controlled release
device proved to be largely dependent on the type of dosage form included.

Hydroxyzine HCl is used in oral formulations for the treatment of urticaria and atopic
dermatitis. Dizziness, blurred vision, and anticholinergic responses, represent the most common side
effects. It has been shown that controlled release of the drug from a delivery system to the skin could
reduce the side effects while reducing percutaneous absorption. Therefore, the aim of the present study
was to produce an effective drug-loaded dosage form that is able to control the release of hydroxyzine
hydrochloride into the skin. The Microsponge Delivery System is a unique technology for the controlled
release of topical agents, and it consists of porous polymeric microspheres, typically 10–50 μm in
diameter, loaded with active agents. Eudragit RS-100 microsponges of the drug were prepared by the oil
in an oil emulsion solvent diffusion method using acetone as dispersing solvent and liquid paraffin as the
continuous medium. Magnesium stearate was added to the dispersed phase to prevent flocculation of
Eudragit RS-100 microsponges. Pore inducers such as sucrose and pregelatinized starch were used to
enhance the rate of drug release. Microsponges of nearly 98% encapsulation efficiency and 60–70%
porosity were produced. The pharmacodynamic effect of the chosen preparation was tested on the
shaved back of histamine-sensitized rabbits. Histopathological studies were driven for the detection of
the healing of inflamed tissues.

The present work is a comparative study that matches between carriers and techniques used to prepare solid mixtures with glimepiride. The study is directed towards elucidation of the most promising carrier capable of highly improving drug dissolution along with the most successful technique used for drug formulation. Mixtures were tested for drug content and dissolution. The most optimum formulae were characterized by DSC, IR and XRPD. Kinetic treatment of dissolution data was performed for physical and co-ground mixtures, solid dispersions and their adsorbates, triple solid dispersions and their adsorbates, microwave generated or treated solid dispersions. Results revealed that enhancing effect mostly reached maximum with ternary solid dispersion adsorbate (TSDads). The latter technique demonstrated a dramatic increase in drug dissolution rate which was reflected in the shortest half-life for most carriers at variable degrees. The highest dissolution rate was attained with pregelatinized starch and decreased to variable degrees with remaining carriers. Differences were ascribed to chemical nature as well as relative water solubility of carriers. The combined effects of incorporating surfactants, polymers and adsorbents to glimepiride contributed together to improve wetting, reduce crystallinity and caused substantial increase in the surface area which made TSDads the most promising technique for enhancing dissolution of glimepiride.

This report describes zero-order approximation for metoclopramide hydrochloride sublingual tablet formulation. Effects of type and concentration of excipients on release were investigated. Study revealed that highest rate of dissolution was attained with crosspovidone and decreased in the order crosspovidone > sodium starch glycolate > ac-di-sol. All formulations demonstrated flush release, except the one containing 10% crosspovidone where a lag time of 0.5 min. was depicted. Increasing the concentration of crosspovidone from 5 to 10% gave the same half-life, whereas kinetics of release changed to zero order. Differential scanning colorimetry and infrared spectroscopy did not reveal any sign of physical or chemical interaction between drug and crosspovidone. In order to study the alignment of polymeric network inside tablet matrix, scanning electron microscopy was performed on the tablet and its cross-section. Matrix with 10% crosspovidone showed higher density of interconnections extending to the interior of core enabling fast and constant release. Hence physicochemical characteristics of crosspovidone could be tailored by varying its concentration, in a way that provided a porous matrix with tight arrangement of polymeric chains, resembling to an assemblage of cylinders with constant apertures, from which zero-order release was approached.

Octyl-p-methoxycinnamate (OMC) is a sun-blocking agent that absorbs ultraviolet (UV) radiation in UVB range. However, when exposed to sunlight, OMC is converted into a less UV-absorbent form, which reduces its effectiveness. The aim of this study was to stabilize the oil by microencapsulation and to convert it into a free-flowing powder form. In addition, the study aimed to develop a suitable high-performance liquid chromatography method to detect the oil in the presence of its degradation product. OMC was microencapsulated by the congealable disperse-phase encapsulation using carnauba wax (cw) and beeswax (bw) at different wax-to-drug ratios (2:1 and 4:1). The photostability of the oil was investigated by exposing the microspheres to UV radiation. After 180 min of exposure, the photoprotective abilities of all the tested formulae were similar and reached about 82%. However, physicochemical assessment showed superiority of cw microspheres over their bw analogues.