Publications by authors named "C J Betlach"

Porcine reproductive and respiratory syndrome virus (PRRSv) is an economically significant swine pathogen causing production losses in the global swine industry. Clinical impact depends on many factors including the virus itself. One method to sub-type PRRSv is using restriction fragment length polymorphism (RFLP).

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The extent of absorption of carbamazepine from a 2-hydroxypropyl-beta-cyclodextrin/carbamazepine complex was significantly greater and the rate of absorption was faster when compared with an immediate-release carbamazepine tablet in the dog. Six dogs were dosed orally in a two-way crossover study in which the tablet was compared with an equivalent dose of the complex in solution. The area under the curve of concentration versus time for the complex was 5.

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Prior to evaluating the effect of ranitidine on theophylline absorption from a sustained-release theophylline tablet, the effect of ranitidine on the time course of gastric pH in 12 healthy subjects was evaluated with an encapsulated radio-telemetry device (Heidelberg capsule). Gastric pH was measured hourly from 7 AM to 1 PM prior to beginning ranitidine treatment at 2 PM (150 mg every 4 hr for eight doses). The next day, pH was again measured hourly from 7 AM to 7 PM.

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The bioavailability of a new sustained-release potassium chloride (KCl) tablet, designed for once-a-day dosing, was compared to a KCl elixir using urinary excretion data. The study utilized 25 male volunteers dosed in a crossover design in a dietary/activity-controlled environment. The regimens consisted of a total of 80 mEq of potassium in three equally divided doses of elixir every 6 hr and a single 80-mEq dose using four 20-mEq sustained-release (SR) tablets.

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The dynamic interaction between variables within the gastrointestinal tract and the physiochemical properties of a drug in a delivery system determine the rate and extent of absorption of that drug. Among the major physiologic variables are pH, gastric emptying time, and intestinal transit time. Some physicochemical properties of interest include solubility, particle size, and chemical form of the drug.

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