CB4 -- Kinetics of time-release vitamin C tablets: A new twist on a classic experiment
Document Type
Event
Abstract
We report on a new variation of the classic vitamin C titration experiment. In its traditional form, students use titration to find the amount of vitamin C present in an over-the-counter supplement tablet and compare their values against the amount of vitamin C officially listed on the product label. Pedagogically, this experiment is useful as a method to teach students about titration in context of a common consumer product. Additionally, the traditional experiment also allows students the opportunity to learn that only a portion of the total mass of a tablet or pill is the active ingredient, because nearly all tablets and pills contain inactive ingredients know as excipients that facilitate manufacturing the tablet or help the drug delivery process. In our new version of the vitamin C experiment, we investigate the properties associated with time-release vitamin C tablets. Pedagogically, this is very useful because the time-release properties allow instructors to incorporate important chemical kinetics ideas into the experiment such as reaction rates, reaction orders, and rate constants. Thus, in addition to the traditional question that only asks “How many milligrams of vitamin are in a 500 mg vitamin C tablet?” we can now also ask questions like: “How long does the time-release last?” and “What is the reaction order for the dissolution of vitamin C in the time-release tablet?” We have measured that one particular brand of time-release vitamin C tablets follows an approximately first order process with a rate constant, k= 0.07/min. The total release of vitamin C takes approximately 75 minutes. Furthermore, this is even more interesting as an investigation because there are many possible excipients with many potential time-release strategies. Thus, time-release kinetics could potentially vary from brand-to-brand as different manufacturers could make different decisions on how they design their time-release kinetics.
Keywords
Chemistry, Biochemistry
CB4 -- Kinetics of time-release vitamin C tablets: A new twist on a classic experiment
URC Greatroom
We report on a new variation of the classic vitamin C titration experiment. In its traditional form, students use titration to find the amount of vitamin C present in an over-the-counter supplement tablet and compare their values against the amount of vitamin C officially listed on the product label. Pedagogically, this experiment is useful as a method to teach students about titration in context of a common consumer product. Additionally, the traditional experiment also allows students the opportunity to learn that only a portion of the total mass of a tablet or pill is the active ingredient, because nearly all tablets and pills contain inactive ingredients know as excipients that facilitate manufacturing the tablet or help the drug delivery process. In our new version of the vitamin C experiment, we investigate the properties associated with time-release vitamin C tablets. Pedagogically, this is very useful because the time-release properties allow instructors to incorporate important chemical kinetics ideas into the experiment such as reaction rates, reaction orders, and rate constants. Thus, in addition to the traditional question that only asks “How many milligrams of vitamin are in a 500 mg vitamin C tablet?” we can now also ask questions like: “How long does the time-release last?” and “What is the reaction order for the dissolution of vitamin C in the time-release tablet?” We have measured that one particular brand of time-release vitamin C tablets follows an approximately first order process with a rate constant, k= 0.07/min. The total release of vitamin C takes approximately 75 minutes. Furthermore, this is even more interesting as an investigation because there are many possible excipients with many potential time-release strategies. Thus, time-release kinetics could potentially vary from brand-to-brand as different manufacturers could make different decisions on how they design their time-release kinetics.