Gilbert S. Banker

Development of Biodegradable and Injectable Latices for Controlled Release of Potent Drugs

AbstractA new dosage form designed to provide parenteral drug delivery over a prolonged period of time following a standard injection has been investigated using testosterone as the model drug. The drug carrier consists of a biodegradable, biocompatible polymer in which the drug is dispersed on a molecular level. The polymer itself is formulated as a pseudolatex with high solid content (40.0%). The formulation has a low viscosity (97 cps) which can be injected easily through a hypodermic needle. The histopathology study showed good tissue compatibility of the pseudolatices and in-vivo tests on rats confirmed a prolonged release of drug over a 14 day period. The stability of the biodegradable poly-d, l-lactic acid latex was found not to be significantly changed over 120 days of storage at room temperature (25°). A six month study showed a slight increase (10%) in the viscosity of the parenteral product when stored at room temperature. The increase was attributed to partial coalescence of the polymer partic...

Water vapour transmission properties of free polymer films

The water vapour transmission properties of selected hydrophilic, lipophilic, and mixed hydrophilic‐lipophilic polymer systems, cast as free films, have been examined as a function of time, film thickness, plasticiser concentration, and film formulation. An inverse linear relationship was established between the logarithm of the water vapour transmission rate (Rwvt) and the logarithm of film thickness in the presence of the various plasticiser concentrations for the three systems studied. The lipophilic n‐butyl methacrylate films were found to be less permeable to moisture than either the hydrophilic hydroxypropyl cellulose or mixed methyl hydroxypropyl cellulose‐ethyl cellulose films. The butyl methacrylate films closely follow Fickian diffusion, whereas the permeability constants of the other two films increased linearly with film thickness over the range of thicknesses studied. These phenomena are discussed with respect to the relative attractions these films have for water vapour.

Tissue Irritation Evaluation of Potential Parenteral Vehicles

AbstractTwenty-three potential nonaqueous parenteral vehicles were evaluated for tissue irritation in chicken pectoral muscle. Benzyl benzoate, 1,3-butylene glycol, ethyl oleate, glyceryl triacetate, sesame oil and sesame oil: benzyl benzoate (1:1) were found to cause minimal tissue irritation.

Evaluation of Hydroxypropyl Cellulose and Hydroxypropyl Methyl Cellulose as Aqueous Based Film Coatings

AbstractAqueous solutions of hydroxypropyl cellulose and hydroxypropyl methyl cellulose were evaluated as pharmaceutical film coatings from completely water based systems. The first phase of the study was to identify suitable plasticizers for the two polymers. The second was to examine possible interactions between the polymer solutions, and new color concentrates prepared for aqueous coating systems, based on viscosity measurements. The third phase of the study was to coat tablets with the various polymer aqueous solutions, in an air suspension tower, and in a side-vented coating pan, (while establishing coating conditions for each process). The final phase of the study was to evaluate the tablets coated by the various formulations.

Microbiological Considerations of Polymer Solutions Used in Aqueous Film Coating

AbstractEnvironmental and other pressures are causing pharmaceutical manufacturers to convert earlier developed solvent based film coating procedures to aqueous systems. Factors influencing microbiological proliferation in cellulosic polymer solutions are discussed. Commonly employed water soluble cellulosic polymers have been evaluated for their resistance/susceptibility to microbiological growth. The implications of the findings to the use of such aqueous polymer solutions as pharmaceutical film coatings are discussed

Management Science Aids in Expediting Pharmaceutical Product Designs

AbstractA new philosophy is proposed for obtaining improved product designs in shorter time periods using established concepts from engineering and management science. This philosophy is a simple systematic approach with sufficient flexibility to serve various product types, different time frames for action, and achieve a variety of conditions of acceptance. Four phases of effort make up the product design regimen. Each phase must be managed by selecting the appropriate techniques and allocating research and development efforts. Two case studies are presented to illustrate this philosophy.

The Determination of the Entrapment Efficiency for a Molecular Dispersion System

AbstractThe entrapment of d-propoxyphene in ethyl cellulose pseudolatex systems was studied. Heat of fusion measurements were used to determine the extent of molecular scale entrapment. When δHf = 0, the drug was assumed to he entrapped on a molecular level while δHfvalues greater than zero indicated the presence of crystal structure. Zeta potential measurements were also used to indicate the point of maximum entrapment efficiency. A good correlation was obtained between zeta potential and heat of fusion measurements.

Mechanism of Molecular-Scale Drug Entrapment Using Colloidal Polymeric Latices

AbstractThe mechanism of a molecular-scale entrapment of cationic drug by negatively charged latices was investigated using the measurement of zeta potential as a physical/analytical tool. It was found that as the amount of the drug was increased the zeta potential of latex particles decreased. The simultaneous presence of a dicarboxylic acid with the drug increased the zeta potential. Entrapment products were prepared using diluted latices, a cationic drug (Chlorpromazine hydrochloride), and an entrapment facilitator (succinic acid). The dissolution of the drug from the products was found to be first order in all cases. The data showed that (a) the smaller the particle size the faster the release rate, (b) the order of combination (latex to drug or vice versa) did not affect the release rate, and (c) the use of entrapment facilitator (a dicarboxylic acid), did not change the release rate but increased the amount of drug entrapped. The agreement of the first order dissolution and the first order desorptio...

Bisbigijanide-Imduced Staining in Oral Hygiene

AbstractThe use of a class of antimicrobial agents, the bisbiguanides, in oral hygiene and their involvement in the formation of teeth staining are reviewed. Particular attention is placed on a discussion of the mechanism of bisbiguanide-induced staining from a molecular level and the approaches taken to resolve this staining problem.

Tableting Production Times, Costs and Risks Through-Simulation

AbstractAs the methods of preparation of pharmaceutical compressed tablets are examined, it becomes evident that there are a number of cost factors which may be significant. These cost factors my be of paramount importance in decision making as to the method of preparation. A comparative study was done to evaluate costs involved in the preparation of tablets by direct compression or the wet granulation procedure at two batch sizes. A simulation model for the processing was used for analysis of the system to optimize batch size, procedure and cost.