In vitro and in vivo evaluation in rabbits of a controlled release 5-fluorouracil subconjunctival implant based on poly(D,L-lactide-co-glycolide).

Purpose: To design a controlled release 5-fluorouracil (5-FU) implant to provide prolonged antifibroblast concentrations of 5-FU in the subconjunctival tissues but low concentrations of 5-FU in other ocular tissues.

Method: Implants (5 mg; 2.5 mm diameter x 1.

Evaluation of poly(isobutylcyanoacrylate) nanoparticles for mucoadhesive ocular drug delivery. I. Effect of formulation variables on physicochemical characteristics of nanoparticles.

A factorial design was applied to evaluate the effect of formulation variables on physicochemical properties of poly(isobutylcyanoacrylate) nanoparticles. Formulation variables were dextran T40 or T70 and Pluronic F68 or Tween 20 acting as stabilizer and surfactant respectively, and three pH levels (2, 4 and 7). Nanoparticles possessed unimodal particle size distribution with significant effect of dextran, surfactant and pH.

Determination of small sample volumes in the analysis of drugs at specific sites in the oral cavity.

Two methods for the determination of sample volumes between 0.2 and 0.6 microliters were compared by preparing standard curves for volumes over this range.

Stability of dantrolene oral suspension prepared from capsules.

The chemical stability of an extemporaneously compounded dantrolene oral suspension (5 mg/ml dantrolene sodium) in Syrup BP containing citric acid with and without methyl hydroxybenzoate preservative was studied on storage at 5, 25 and 40 degrees C for 150 days in high density polyethylene dispensing bottles. The amount of dantrolene free acid in suspension was monitored by a stability indicating HPLC assay. There was no significant decomposition of dantrolene under all storage conditions irrespective of the presence of preservative.

The release of macromolecules from fatty acid matrices: complete factorial study of factors affecting release.

A replicated complete factorial design to study the main effects and interactions of four factors: bovine serum albumin (BSA) particle size (Factor A); stearic acid particle size (Factor B); BSA loading (Factor C); and compression force (Factor D), on the release of BSA from compressed stearic acid pellets was performed in isotonic phosphate buffer pH 7.4 at 37 degrees C. Samples were withdrawn over 64 h.

Immunopotentiation and delivery systems for antigens for single-step immunization: recent trends and progress.

The use of adjuvants for immunopotentiation has been investigated since the 1920s and a number of comprehensive reviews and monographs have been published on this subject. A recent trend in immunopotentiation has been the use of delivery systems which allow for sustained or controlled release of antigens and which induce prolonged immunity following a single dose. This concept has been termed either single-step or single-shot immunization.

A study of the phase transition behaviours of cholesterol and saturated egg lecithin, and their interaction by differential scanning calorimetry.

The thermal behaviours of hydrogenated egg lecithin (PC) and cholesterol (C) in anhydrous form and in aqueous dispersions were studied by differential scanning calorimetry. The role of C in phase transitions of C-PC mixtures prepared by physical mixing or coprecipitating from chloroform has been examined. C underwent a phase transition at 34 degrees C and a second one at 76-78 degrees C which depended on the thermal history of the samples.

The behaviour of bioadhesive betamethasone tablets in the mouth.

Disk-shaped adhesive tablets, for treatment of mouth lesions, were prepared by direct compression of a mix of high viscosity sodium carboxymethyl-cellulose and 0.061% betamethasone valerate. They were evaluated in six healthy volunteers.

A method to study the kinetics of oral mucosal drug absorption from solutions.

A method has been developed which allows the kinetics of oral mucosal drug absorption from solutions to be studied in a single 15-20 min test. This is an improvement over the traditional buccal absorption test which requires a separate experiment for each time point, thus taking days for each kinetic profile. It should also allow for disappearance of drug from the mouth and appearance in the plasma to be monitored simultaneously.

Characterization of sodium carboxymethylcellulose-gelatin complex coacervation by chemical analysis of the coacervate and equilibrium fluid phases.

The complex coacervation of sodium carboxymethylcellulose (SCMC) and gelatin has been characterized by chemical analyses of the coacervate and equilibrium fluid phases. The phenol-sulphuric acid (for SCMC) and Lowry (for gelatin) assays were used. Chemically analysed coacervate yield was used to predict optimum coacervation conditions, which occurred at a SCMC-gelatin mixing ratio of 3:7 at pH 3.

Characterization of sodium carboxymethylcellulose-gelatin complex coacervation by viscosity, turbidity and coacervate wet weight and volume measurements.

A sodium carboxymethylcellulose (SCMC) and gelatin coacervation system has been evaluated and characterized and the effects of pH and colloid mixing ratio on the coacervation process investigated. The colloid mixing ratio at which optimum coacervation occurred varied with the coacervation pH. A viscometric investigation of various isohydric SCMC-gelatin mixtures was used to predict optimum conditions for complex coacervation.

The GMC project: a current investigation of the development of a large population of hearing-impaired children.

This report of work in progress describes the GMC project, an investigation of the language and development of hearing-impaired children born within the Greater Manchester area in the years 1977-1980 inclusive. The aim of the language section of the project is to describe the acquisition and development of spoken language by a complete population of children with sensori-neural hearing loss. Comprehensive audiological, aetiological and sociological background information is kept as well as the results of standardized psychological and language tests and videotaped samples of spontaneous language.

Interactions of ionic and non-ionic surfactants with plasma low density lipoprotein.

Surfactants might be useful in facilitating the replacement of the interior of low density lipoprotein (LDL2) (p = 1.02-1.063 g ml-1) with drug molecules.

Estimation of all parameters from nonisothermal kinetic data.

A method is described which estimates (using least-squares analysis) all parameters (kinetic parameters and also zero and infinite time assays) from nonisothermal kinetic data. This method overcomes the time delays required for infinite time assays and biased estimates caused by the use of those assay results. Flexible temperature and data collection programs can be used.

Health risks following ingestion of mercury and zinc air batteries.

This paper reports on a study set up to assess the corrosive behaviour of mercury and zinc air batteries in the gastric juice environment of the stomach. The results show a relatively rapid rate of corrosion for charged mercury batteries. In contrast, the zinc air battery showed no visible corrosion under the same conditions.

An investigation into the problems involved in producing efficient ear moulds for children.

The problems involved in producing efficient ear moulds for children have been examined. It is suggested that materials do exist such that the general quality of ear moulds could be significantly improved. However, manufacturing techniques require modification and a more comprehensive training programme for ear mould technicians is urgently required.

A new high-efficiency earmould.

The problems associated with earmoulds currently used by hearing-impaired persons, particularly children, are outlined. A new type of earmould which combines high efficiency with minimal feedback is described and evaluated.