Biomedical subjects

Marilyn N Martinez

Publications and source records attributed to Marilyn N Martinez.

5 recordsLinked to original sources

PubMed2005

A SAS/IML program for simulating pharmacokinetic data.

Data simulation can be an invaluable tool for optimizing the design of bioequivalence trials. It can be particularly useful when exploring alternative approaches for assessing product comparability especially in the context of encountering various complex experimental situations that can occur in veterinary medicine. With this in mind, we designed a novel SAS/IML program to generate pharmacokinetic datasets that reflect the various kinetic, population, and study design characteristics that complicate the bioequivalence evaluation of animal health products. Developing this simulation program within SAS provides an opportunity to utilize the statistical capabilities of this software platform.

Animals↗

PubMed2003

AAPS/RAPS/CAPRA collaborative program: exploring the challenges of drug regulation in a global environment: clinical concerns.

Globalization of the pharmaceutical industry has led to a need to harmonize the regulatory requirements governing the marketing of medicinal products. To minimize the barriers impeding global drug product registration, the International Conference on the Harmonization of Technical Requirements of Pharmaceuticals for Human Use (ICH) was established in 1990. The ICH has developed a series of guidelines that reflect agreements reached by participating nations on aspects of the chemistry and clinical technical sections that will fulfill the regulatory requirements of these various jurisdications. Nevertheless, there continue to be points of divergent perspectives and barriers that can impede the use of foreign clinical data. Given the importance of these issues, the Regulatory Science (RS) section of the American Association of Pharmaceutical Scientists (AAPS), in conjunction with the Regulatory Affairs Professional Society (RAPS) and the Canadian Association of Professional Regulatory Affairs (CAPRA) cosponsored a public forum on this topic. This manuscript provides a summary of the speaker presentations and audience discussions regarding the design of clinical trials and the extrapolation of results from these trials to support international drug registration.

Clinical Trials as Topic↗

PubMed2002

Modified release drug delivery in veterinary medicine.

To successfully research and develop an animal pharmaceutical dosage form, a diverse array of issues covering basic medicine, pharmacology and technology must be addressed. Societal concerns regarding animal and public health, as well as the rapidly changing farming and economic environments, provide additional challenges that require integration into an already complex web of issues. Here, we examine the drive towards reducing the frequency of administration to animals and the closing of gaps between the human and veterinary drug product development.

Animals↗

PubMed2002

A methacholine challenge dose-response study for development of a pharmacodynamic bioequivalence methodology for albuterol metered- dose inhalers.

BACKGROUND: With the expiration of the patent on albuterol metered-dose inhalers (MDIs) in 1989, methods to assess in vivo bioequivalence of generic formulations required investigation. OBJECTIVE: In an effort to develop a sensitive method to document bioequivalence, bronchoprovocation with methacholine chloride was used to assess the dose-response relationship of albuterol as delivered by MDI. Sensitivity was assessed in terms of magnitudes of ED(50), the estimated albuterol dose required to achieve 50 % of the fitted maximal value of the pharmacodynamic effect above baseline, and change in response as a function of dose, with emphasis on 1 and 2 actuations. METHODS: On separate study days, 15 nonsmokers with mild asthma received randomized nominal albuterol doses of 0 to 576 microg by using specially manufactured MDI canisters. FEV(1) was measured 15 minutes after MDI dosing. Serially increasing doses of methacholine were administered, and FEV(1) was measured after each methacholine dose until a 20 % decrease in FEV(1) (PD(20)) was achieved. RESULTS: Mean PD(20) values after use of each of the albuterol-containing MDIs were significantly greater than either mean screening or mean placebo PD(20) values (P <.05). Mean responses and most individual subject responses to 1 and 2 actuations (90 and 180 microg) of albuterol MDI were within the sensitive region of the dose- response curve. The mean estimated ED(50) value on the basis of nonlinear mixed effect modeling was 119.2 microg (range, 33.3-337.1 microg), with an intersubject percentage coefficient of variation of 69.0 %. CONCLUSIONS: The methacholine bronchoprovocation model is safe and useful in the study of albuterol MDI dose-response in asthmatic subjects. Bronchoprovocation studies may be used for determination of bioequivalence of multisource albuterol MDI products.

Administration, Inhalation↗

PubMed2002

A mechanistic approach to understanding the factors affecting drug absorption: a review of fundamentals.

This article provides an overview of the patient-specific and drug-specific variables that can affect drug absorption following oral product administration. The oral absorption of any chemical entity reflects a complex spectrum of events. Factors influencing product bioavailability include drug solubility, permeability, and the rate of in vivo dissolution. In this regard, the Biopharmaceutics Classification System has proven to be an important tool for predicting compounds likely to be associated with bioavailability problems. It also helps in identifying those factors that may alter the rate and extent of drug absorption. Product bioavailability can also be markedly influenced by patient attributes such as the integrity of the gastrointestinal tract, physiological status, site of drug absorption, membrane transporters, presystemic drug metabolism (intrinsic variables), and extrinsic variables such as the effect of food or concomitant medication. Through an awareness of a drug's physicochemical properties and the physiological processes affecting drug absorption, the skilled pharmaceutical scientist can develop formulations that will maximize product availability. By appreciating the potential impact of patient physiological status, phenotype, age, gender, and lifestyle, dosing regimens can be tailored to better meet the needs of the individual patient.

ATP Binding Cassette Transporter, Subfamily B, Mem↗