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Biomedical subjects

R Gurny

Publications and source records attributed to R Gurny.

At least 109 records · Page 6Linked to original sources
PubMed1987

Osmotic water transport through cellulose acetate membranes produced from a latex system.

The advisability of a progressive curtailment of organic solvent film coating offers an incentive to develop latex systems. Here, the use of aqueous colloidal dispersions of cellulose acetate, plasticized with water-soluble additives, is proposed as an alternative way to obtain cellulose acetate membranes either by casting or spraying. The osmotic water permeability of both kinds of films was measured, as well as their loss of leachable materials and degree of swelling in a saturated solution of potassium chloride. The permeabilities varied over a wide range depending on the physicochemical properties of the plasticizer and its initial concentration in the latex, and on the conditions for coating (temperature, rate of spraying, and drying duration). High boiling point plasticizers gave more permeable films. Films prepared by casting were found to be sensitive to their sodium dodecyl sulfate content.

Cellulose↗
PubMed1987

Determination of pilocarpine by HPLC in presence of isopilocarpine a pH-sensitive polymer in ophthalmic dispersions.

Quantification of pilocarpine in the presence of the epimer isopilocarpine in polymeric dispersions is reported. The method describes a technique using reversed-phase HPLC and UV detection of pilocarpine in the presence of a pH-sensitive polymer. As this method does not require prior sample preparation it will be of special interest for process control and development.

Journal Article↗
PubMed1987

Mechanically strong films produced from cellulose acetate latexes.

Mechanically strong films, comparable with those obtained from organic solutions, can be produced from cellulose acetate latexes, a new type of dispersion, both by casting and spraying. The prerequisite conditions for high strength, which include choice of water-soluble plasticizers possessing some degree of volatility, are discussed.

Cellulose↗
PubMed1987

Influence of sodium hyaluronate on the meiotic effect of pilocarpine in rabbits.

Sodium hyaluronate is a potential vehicle for drugs given topically to the eye. In the present study, the effect of sodium hyaluronate on the miosis induced by pilocarpine in rabbits was investigated. Addition of 0.2 and 0.75% sodium hyaluronate to 1% pilocarpine hydrochloride in buffer resulted in an increased effect measured as area under the miosis-time curve (AUC) and duration of miosis. A comparison between a commercially available 1% pilocarpine preparation and the preparations containing sodium hyaluronate showed that sodium hyaluronate improves the effect parameters. No adverse effects with sodium hyaluronate were observed. Possible mechanisms inducing these improvements are discussed.

Animals↗
PubMed1984

Bioadhesive intraoral release systems: design, testing and analysis.

The aim of this study was to analyse the adhesion of various polymeric formulations and to measure the in vitro release of a local anaesthetic (febuverine hydrochloride) from a hydrophobic gel containing 34% (wt/wt) adhesive hydrocolloids. The bioadhesive polymer system was prepared from a polyethylene gel containing various amounts of sodium carboxymethylcellulose (NaCMC) as the adhesive, and hydrolysed gelatin as the water sensitive material to ensure rapid swelling. Upon hydration, adhesion studies were performed with a tensile tester equipped with a custom-made cell. The controlled release of the active ingredient was studied with a dissolution cell filled with artificial saliva at 37 degrees C. It was found that the relative adhesive bond strength of the formulations was dependent on the NaCMC content, showing a maximum at about 20 wt %. Febuverine hydrochloride release achieved an optimal release rate for formulations with NaCMC in the range of 12-25 wt %.

Adhesiveness↗
PubMed1983

Mechanisms of potassium chloride release from compressed, hydrophilic, polymeric matrices: effect of entrapped air.

The release of potassium chloride from hydroxypropyl methylcellulose matrices was investigated for tablets prepared with several different compression forces. It was determined that the release kinetics for these systems deviates significantly from the classical t1/2 dependence. This behavior was attributed to air entrapped in the matrix during preparation. Removal of the air prior to release restored the traditional t1/2 behavior.

Air↗
PubMed1982

Modelling of sustained release of water-soluble drugs from porous, hydrophobic polymers.

The release behaviour of water-soluble drugs from hydrophobic, porous polymeric matrices is complicated by the dissolution of the drug in the water-filled pores under quiescent conditions. Mathematical models are presented for drug release above and below the solubility limit of the drug in the dissolution medium, for constant void fraction (porosity). Experimental studies of KCl release from the porous ethyl cellulose tablets in water at 37 degrees C are explained in terms of dissolution-controlled and diffusion-controlled steps of the release mechanism.

Delayed-Action Preparations↗