Compounding and testing of three modified elastomers as parenteral stopper

Tetramethylthiouram disulphide TMTD is known as vulcanizing agent alone or with mercaptobenzothiazole [MBT] in the presence of small quantity of sulfur. Different concentrations of TMTD were added to natural crepe and to bromobutyl rubber mixes in 0.5-3% w/w of rubber at different curing temperatures [140-160C]. It was found that the addition of 2% TMTD for each one of the two elastomers at 150C yielded products with good physicomechanical and swelling properties. When the vulcanizing system of 2% TMTD and 0.1% MBT was used, a delay in the cure time [Tc90] and an increase in the scorch time [TS2] were observed, the effect of blending the natural and bromobutyl rubber mixes in different% showed that increasing the natural rubber [NR] in the blends up to 40% arose the cure time and improved the physicomechanical and swelling properties. The optimal percentage was found to be 30% NR and 70% BR. Three formulations of natural [no 13], bromobutyl [no 14] and their blend [30NR-70BR] [no 18] were subjected to the suitability tests as parenteral stoppers. The results of aging indicated that the three elastomers possess good heat and oxidation resistance characteristics and are also suitable for sterilization. The suitability tests according to the international standards proved that the three elastomers have a suitable limits of physicomechanical and chemical properties

Effect of three rubber elastomers on the stability of amikacin and kanamycin in parenteral solutions

Three rubber elastomers [natural, bromobutyl and their blend] were prepared, exhibited good physicomechanical and chemical properties and suitable for use as parenteral stoppers. The effect of these elastomers on the stability of amikacin and kanamycin in solutions was investigated. The three elastomers were found to augment the loss of each antibiotic upon storage. The loss increased with time. The effect was more pronounced at 60C rather than at 25C. Bromobutyl elastomer showed the least determinative effect towards the antibiotic potency relative to the reference elastomer, as it exhibited the lowest sorption characteristics than the natural elastomer. Leached materials from rubber elastomers slightly affected the loss of antibiotics from solutions

Effect of addition of melamine/formaldhyde resin on the physical and mechanical properties of three rubber formulations

It has been found that the addition of melamine/formaldehyde resin by miling to natural [Pale crepe], synthetic [acrylonitrile-butadiene], and blend of the two [1: 1] vulcanizates gives some improvement in the physical and mechanical properties. These include tensile strength, elongation, modulus 300%, hardness sh, degree of swelling and the extracted soluble matter by some solvents

Modified formulation of natural rubber to be used as parenteral stoppers

Two modified natural rubber formulas were prepared. Ten parts melamine/formaldehyde per hundred parts of rubber were added to get suitable physico-mechanical and chemical properties. A comparative study between the two modified vulcanizates and a commercial rubber closure used by drug companies were carried out to investigate the validity of the suggested formulas to be used as parenteral stoppers