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R L Braun

Publications and source records attributed to R L Braun.

3 recordsLinked to original sources
PubMed1991

Development of a new controlled-release formulation of chlorpheniramine maleate using in vitro/in vivo correlations.

Development of a controlled-released formulation of chlorpheniramine maleate is described, using in vitro/in vivo correlates, according to a process that has been termed "biorelevant dissolution". The process begins with simulations using several possible input rates combined with known disposition parameters of chlorpheniramine maleate. Based on desired plasma concentrations, an input rate is selected for further development which consists of a combination of clinical bioequivalence studies and further in vitro testing and simulations. The method is designed to reduce the requirements for trial and error clinical bioequivalence testing of a new controlled-release formulation.

Administration, Oral↗
PubMed1989

Phenotypic differences in dextromethorphan metabolism.

Polymorphic differences in dextromethorphan metabolism were observed in three studies conducted in a total of 44 subjects (of Dutch origin) administered 60 mg dextromethorphan hydrobromide as an OROS tablet. Mean plasma dextromethorphan (DM) concentrations after a single dose and at steady state were 4-75 times higher in the poor metabolizers (PM) relative to the extensive metabolizers (EM). Following a single dose, the mean areas under the plasma concentration-time curve (AUC, 0-24 hr) of DM, total dextrorphan (DR), and total 3-hydroxymorphinan (HM) were 6.9-fold higher, 17.4-fold lower, and 11-fold lower, respectively, for the PM than for the EM. Correspondingly, steady-state AUC values were 52.8 times higher, 6.7 times lower, and 3.3 times lower for DM, total DR, and total HM, respectively, for the PM relative to the EM. Drug/metabolite ratios (DMR) for amounts excreted in the urine of DR and HM indicated polymorphism in O-demethylation of DM since DMR for PM was 352 and 338 times higher than that for EM for DR and HM, respectively. However, polymorphism in N-demethylation was not observed. Ratios of conjugated/free dextrorphan and 3-hydroxymorphinan excreted in the urine suggest also a lack of conjugative capacity in the PM, relative to the EM. The overall incidence of PM was 9.1% in this population.

Administration, Oral↗