Purpose : The aim of present work was to investigate the in vitro release profile of diclofenac sodium from matrix tablets, which were prepared using guar gum with and without probiotics. Methods : Six matrix tablets formulations (F1-F6) of diclofenac sodium containing varying proportions of guar gum, 10-60% of tablet weight were prepared by wet granulation method and evaluated in vitro for their release profile. Four matrix tablets formulations (F7-F10) of diclofenac with guar gum (40%) were prepared incorporating varying concentration of commercial spores of lactobacillus and bifidobacterium species that are commonly found in colon microflora. Results : The tablets having same concentration of guar gum without probiotics (F4) showed a 54.47% cumulative release of diclofenac after 24 hr while that in presence of probiotics (F9) was 73.01%. These drug release studies were conducted without rat caecal content. In another set of experiments, the drug release studies were carried out in presence of rat caecal content. In such experiments, more than 95% drug was released from F4 and F9 formulations after 24 hr. Conclusion : The results showed that commercial probiotics are capable in digesting guar gum. These probiotics may be used to assist in colon delivery of drugs from formulations prepared with guar gum.

Colon --- diclofenac --- guar gum --- matrix tablet --- probiotics

The aim of the present work was to develop controlled release matrix formulation of nifedipine and investigate the effects of both hydrophilic and hydrophobic polymers on in vitro drug release. Matrix tablets were prepared by wet granulation technique using different concentration of hydroxy propyl methyl cellulose (HPMC), ethyl cellulose (EC), compressible Eudragits (RSpo and RLpo) and their combination in different ratios to examine their influence on tablet properties and drug release profile. Tablets were evaluated by measurement of hardness, friability, content uniformity, weight variation and drug release pattern. Release studies were carried out using USP type II apparatus in 900 ml of sodium phosphate buffer (pH 7.4) with 0.5% (w/v) SDS. The amount of drug released was determined at 238 nm by UV-visible spectrophotometer.In vitro dissolution studies indicated that hydrophobic polymers significantly reduced the rate of drug release compared to hydrophilic ones in 12 hrs and combination of both polymers exhibited the best release profile to sustain the drug release for prolong period of time. As a result, the tablet containing HPMC:EC in ratio of 0.75:1 showed better controlled release pattern over a period of 12 hrs. In selected formulation, the calculated regression coefficients for release models fitted best to zero-order models.

Controlled release --- matrix tablet --- nifedipine --- release kinetics

The aim of the research work was to develop cyst-targeted alginates microspheres of diloxanide furoate (DF) for the effective treatment of amoebiasis. Calcium alginates microspheres of DF were prepared using emulsification method using calcium chloride as a cross-linking agent. Alginate is a natural polysaccharide found in brown algae. Alginates are widely used in the food and pharmaceutical industries and have been employed as a matrix for the entrapment of drugs, macromolecules and biological cells. Alginate microspheres produced by the emulsification method using calcium chloride. Formulations were characterized for particle size and shape, surface morphology, entrapment efficiency, and in vitro drug release in simulated gastrointestinal fluids. XRD and differential scanning calorimetery were used to confirm successful entrapment of DF into the alginates microspheres. All the microsphere formulations showed good % drug entrapment (73.82΁1.99). Calcium alginate retarded the release of DF at low pH (1.2 and 4.5) and released microspheres slowly at pH 7.4 in the colon without colonic enzymes.

Amoebiasis --- colon targeting --- diloxanide furoate --- microspheres --- sodium alginates

The objective of this work was to improve on the solubility of ibuprofen using two vegetable oil-based self-emulsifying formulations (SEFs) and to evaluate the potential usefulness of Carbosil^; (CARB) and Landolphia owariensis latex (LOL) in them. Isotropicity, drug solubility, viscosity, emulsification time (EMT), drug release, aqueous dilution, postemulsification drug precipitation and refrigeration tests were carried out on the coconut oil (CO) and shea butter oil (SBO)-based SEFs. Results showed that only four out of nine batches of the SEFs passed the preformulation isotropicity test. A 100-mg quantity proved to be the maximum amount of drug that could be dissolved by the SEFs to form a stable solution. After 72 hrs all the SEFs still retained stability. All of CO SEFs witnessed remarkable phase separation or drug precipitation However, SBO SEFs having oil:surfactant:cosurfactant ratio of 35:45:20 and containing LOL or LOL-CARB blend lost isotropicity or displayed drug precipitation 6 months later. Refrigeration temperature did not introduce any form of instability or phase separation. Similar viscosities were recorded by the two oil-based SEFs. However, little but inconsistent variation in viscosity was observed between SBO SEFS and LOL-containing SEFs. Aqueous dilution and postemulsification drug precipitation test indicated absence of phase separation and drug precipitation, respectively. Drug-release studies showed that the t ₅₀ of SBO SEFs almost ranked equally with SBO SEFs containing LOL. CO SEFs emulsified at a longer time than those of SBO. SEFs distinctly recorded higher EMTs than those with LOL or CARB-LOL blend. In conclusion, solubility of ibuprofen was improved, CARB gelled the SEFs while LOL reduced their EMTs.

Carbosil^® --- coconut oil --- landolphia owariensis latex --- self-emulsifying formulation --- shea butter oil

In the last two decades, there was an extensive research focused on the study of synthetic amphiphilic vesicles, prepared by nonionic surfactants (niosomes). The particle size of these vesicles is critical for their intended therapeutic benefits. Formulation and processing factors affect greatly the physical characteristics of the resulted nanosystems. Therefore, the present work was adopted to investigate how proper manipulation of various formulations and processing factors on vesicular Z-average particle size. The selected variables were membrane additives, [including cholesterol (CHO), dicetylphosphate (DCP) and stearylamine (SA)], sonication time as well as drug loading factor (using mannitol and estradiol). Sorbitan monopalmitate (span 40) niosomes were prepared by the conventional thin film hydration method. Particle size, measured by Photon Correlation Spectroscopy, and polydispersity indices were measured and compared. The results indicated that CHO increased the vesicular size, with 2:1 and 1:1 (span 40:CHO) ratios showing the same size. Sonication reduced the vesicle size by 23, 35 and 42% after 10, 20 and 30 min, respectively. After 30 min, the effect of sonication was minor. The addition of charge inducing agents changed the zeta potential depending on the type of the additives. Surface charge increased the size by 24 and 11% when using DCP and SA, respectively. Drug incorporation increased the vesicle size to an extent based on its aqueous solubility. There were about 35 and 6.2% increase in vesicular size for estradiol and mannitol, respectively, supporting the partitioning of lipophilic drug within the fatty acyl side chains of the bilayer membrane.

Cholesterol --- niosomes --- particle size --- sonication --- span 40