PubMed · 5575321
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
D P Dressler, L Barlyn, W A Skornik. 1971. Viable prosthetic interface.. https://doi.org/10.1002/jbm.820050216
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The extent to which hydrophilic matrix tablets with a propensity to stick to the dissolution apparatus and/or float are susceptible to variations in hydrodynamic conditions during dissolution testing was investigated. Furthermore the usefulness of simple alternatives to the current compendial tests is examined. Swellable hydrocolloid (guar) matrix tablets containing verapamil HCl were evaluated using USP dissolution apparatus I and II. Two additional configurations where an additional single ring and mesh device or a double mesh device was located below the paddle in the dissolution vessel were also evaluated. Tablets were placed on top of the single mesh device or in the compartment formed by the two mesh surfaces of the double mesh device. In all cases near linear (n>/=0.82) release profiles were observed. When using apparatus I it was observed that the highly swellable tablets were fully constricted by the basket within 5-7 h. This prevented further independent movement and unimpeded swelling and coincided with a departure from linear release and increased variability (S.D.</=9.5%). Under standard apparatus II conditions two out of three tablets adhered to the bottom of the dissolution vessel for the duration of the experiment. Consequently their release profiles differed markedly from those obtained under apparatus I conditions (similarity factor, f(2)=30.5) with the release rate being approximately half of that obtained under apparatus I conditions. Adhesion to the dissolution vessel was also observed when paddle speed was doubled to 100 rpm, thus again resulting in large variability (S.D.</=34%). Whilst the averaged single and double mesh configuration profiles were similar to the apparatus I profile (f(2)=57.36 and 61.38, respectively), large variability (S.D.</=11%) occurred with the single mesh configuration due to floating and random adhesion of tablets to the paddle or sampling tubes. Almost superimposable profiles were obtained for the individual tablets (S.D.<3%) when the tablets were located in the compartment formed by the double mesh device. Use of a double mesh device may therefore provide an alternative to current compendial dissolution methods when the reliable determination of the true release kinetics of floating and sticking delivery systems is desired.
The beetle Hemisphaerota cyanea (Chrysomelidae; Cassidinae) responds to disturbance by activating a tarsal adhesion mechanism by which it secures a hold on the substrate. Its tarsi are oversized and collectively bear some 60,000 adhesive bristles, each with two terminal pads. While walking, the beetle commits but a small fraction of the bristles to contact with the substrate. But when assaulted, it presses its tarsi flatly down, thereby touching ground with all or nearly all of the bristles. Once so adhered, it can withstand pulling forces of up to 0.8 g ( approximately 60 times its body mass) for 2 min, and of higher magnitudes, up to >3 g, for shorter periods. Adhesion is secured by a liquid, most probably an oil. By adhering, the beetle is able to thwart attacking ants, given that it is able to cling more persistently than the ant persists in its assault. One predator, the reduviid Arilus cristatus, is able to feed on the beetle, possibly because by injecting venom it prevents the beetle from maintaining its tarsal hold.
OBJECTIVES: To explore and evaluate Alora placebo patch application and maintenance habits of women in order to identify the factors that influence adhesion success. METHODS: This single-center, open-label, placebo, randomized, multiple-application, parallel-group study involved 99 healthy naïve users of transdermal patches. Participants applied and wore an Alora placebo patch for ten consecutive applications of approximately 3.5 days each and evaluated adhesion of the patches twice-daily. Three subgroups comprising participants achieving low, moderate or high adhesion success took part in focus groups to discuss their wear habits, practices and attitudes regarding transdermal patches. RESULTS: There was a significant behavioral component involved in patch adhesion. The habits, practices and attitudes of high achievers were clearly different from the other two subgroups. The three most important issues identified to improve adhesion were: mastering the removal of the patch liner, identifying the best site of application, and developing and implementing techniques to maintain patch adhesion. The Alora placebo patch was well tolerated throughout the study. CONCLUSION: The data showed that there is a learning curve involved in achieving maximal adhesion with a transdermal patch. During the study, a novel patch application method ('press, fold and slide') was demonstrated for the participants. This method was very well received by all participants and was more easily executed than the previous method. An adaptation of this method was incorporated into the Alora patient information leaflet, together with several other changes to help improve adhesion success.