Preliminary evaluation of the immunoenhancement potential of Newcastle disease vaccine formulated as a cationic liposome.

This study evaluates the enhancement of immune response of birds to Newcastle disease (ND) vaccine encapsulated in 1,2-dioleoyl-3-trimethylammonium propane (DOTAP)-based liposomes. The vesicles of the liposomal ND vaccine were physically characterized for shape, particle size and zeta potential. The results of the analyses showed that vesicles of the liposomal ND vaccine were spherical and tightly packed. The mean size distribution was below 100 nm. The mean zeta potential was 24 mV. Sixty experimental birds were then divided into an unvaccinated group, a liposomal ND vaccine group and a live La Sota(®) vaccine group. Both the liposomal ND vaccine and live La Sota(®) vaccine groups were vaccinated orally at 3 and 6 weeks of age. The mean antibody titres, total and differential white blood cell count, and blood chemistry, respectively, were assessed. Ten birds from each group were challenged by oral administration of 0.2 ml virulent Herts 33 strain at 9 weeks of age. The log(2) mean antibody titre induced by the liposomal ND vaccine after secondary immunization of the birds was 9.60±0.95 while that of the live La Sota( (®) ) vaccine was 6.00±0.63. Nine of the 10 challenged birds in the unvaccinated group died while none died from the liposomal ND vaccine group or the live La Sota(®) vaccine group. After the boost vaccination, the chickens vaccinated with the liposomal ND vaccine had a higher mean antibody titre, indicating that encapsulating ND vaccine in DOTAP-based liposome induced significantly higher immunity than the live La Sota(®) vaccine.

Formulation and evaluation of niosomes.

Span 20-based niosome was prepared by lipid film hydration technique and loaded with Newcastle disease vaccine. Three batches with Span 20, cholesterol and dicetyl phosphate in micro molar ratios of 10:10:1; 15:15:1 and 20:20:1 were prepared and evaluated for encapsulation efficiency using haemagglutination test. The morphology of the vesicles was studied by means of transmission electron microscopy. Particle size, zeta potential and polydispersity index were determined by photon correlation spectroscopy using a nanosizer. Adjuvanticity was assessed using haemagglutination inhibition test. The vesicles of Span 20-based niosomes were distinct, near spherical large unilamellar vesicles. The vesicles were of varied sizes (<1000 nm) with the entrapped Newcastle disease vaccine in the core of the vaccine. The zeta potential had a peak at -50 mV. The polydispersity index was 0.68. Haemagglutination inhibition test showed a 71% increment in immune response over that of the marketed La Sota(®) vaccine which had a 60% increment in immune response. The niosomal vaccine did not alter but rather enhanced the immunogenicity of the Newcastle disease vaccine.

The use of liquid self-microemulsifying drug delivery systems based on peanut oil/tween 80 in the delivery of griseofulvin.

Peanut oil and Tween 80 blends devoid of any cosurfactant were employed in the formulation of different batches of liquid self-microemulsifying drug delivery systems (LSMEDDS) and their suitability as vehicles for the delivery of a typical lipophilic drug-griseofulvin-was investigated. The LSMEDDS were evaluated using the following parameters: phase separation, globule size, viscosity, solubility of griseofulvin, and partition coefficient. The release profile of griseofulvin from the optimized LSMEDDS was evaluated in citrate/phosphate buffer solutions of pH 2.0, pH 6.5, and pH 7.4. The results obtained indicated that there was significantly higher (alpha

Preparation and evaluation of mucin-gelatin mucoadhesive microspheres for rectal delivery of ceftriaxone sodium.

Soluble mucin (S-mucin) processed from the small intestines (ileal region) of freshly slaughtered pigs via homogenization, dialysis, centrifugation and lyophilization and its admixtures with type A gelatin were dispersed in an aqueous medium and used to formulate ceftriaxone sodium-loaded mucoadhesive microspheres by the emulsification cross-linking method using arachis oil as the continuous phase. The release profile of ceftriaxone sodium from the microspheres was evaluated in both simulated gastric fluid (SGF) without pepsin (pH 1.2) and simulated intestinal fluid (SIF) without pancreatin (pH 7.4). The microspheres were further evaluated as possible novel delivery system for rectal delivery of ceftriaxone sodium in rats. Release of ceftriaxone sodium from the microspheres in both release media was found to occur predominantly by diffusion following non-Fickian transport mechanism and was higher and more rapid in SIF than in SGF. The results obtained from this study may indicate that ceftriaxone sodium could be successfully delivered rectally when embedded in microspheres formulated with either type A gelatin alone or its admixtures with porcine mucin; hence providing a therapeutically viable alternative route for the delivery of this acid-labile third generation cephalosporin.

Studies of the complexation of chloranilic acid with proguanil.

Studies on the complexation between chloranilic acid and proguanil has been carried out. The chloranilic acid acted as a pi-electron donor. The stoichiometric relationship in the complex was determined by employing the Job's method of continuous variation. The results indicate that the complex exhibits a purple colour and absorbs maximally at 520 nm. Spectrophotometric studies show that the method could be useful in the analysis of proguanil.

Energetics of the adsorption of some drug onto the sclerotium of Pleurotus tuber-regium.

The thermodynamic parameters of the adsorption of iodine, acetyl-salicylic acid [aspirin] sodium salicylate and pyridoxine hydrochloride onto the powder of sclerotium of pleurotus tuber-regium has been studied. Negative delta G values were obtained for the adsorption of the drugs onto the powdered sclerotium. The negative delta G values show that adsorption is favoured in this spontaneous process, that is, the process led to a decrease in the free energy of the system. The free energy of segregation or surface enrichment factor caused by combination of the material was 46. delta H values calculated for the adsorption of the drugs onto the sclerotium were all negative as well as the delta S values. All these indicate that the adsorption was an exothermic process.

Thermodynamic studies of the charge-transfer interactions of chloranilic acid with moclobemide and promethazine hydrochloride.

Spectrophotometric absorption studies gave evidence for the formation of strongly bonded charge-transfer complexes between moclobemide and promethazine hydrochloride with chloranilic acid in non-aqueous media comprising chloroform and 1,4-dioxane. The transitions involved were detected at wavelengths longer than those of the single pure substances in the visible region. Equilibrium constants from the Scott equation could be measured together with other thermodynamic parameters and molar absorptivities at different temperatures. Theoretical arguments are presented as to the spontaneity of these interactions.

Spectrophotometric determination of moclobemide by charge-transfer complexation.

A simple and sensitive spectrophotometric method is described for the assay for the moclobemide. The method is based on the molecular interaction between the drug and chloranilic acid, to form a charge-transfer complex in which the drug acts as n-donor and chloranilic acid as pi-acceptor. Chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with a maximum absorption band at 526 nm. Conformity with Beer's law was evident over the concentration range 4-36 mg 100 ml-1. A complete, detailed investigation of the complex formed was made with respect to its composition, association constant, molar absorptivity and free energy change. The method has been applied successfully to the analysis of commercially available moclobemide tablets with good recovery and reproducibility.