Analysis

Abstract
The specifications and acceptable ranges for nine critical dissolution apparatus variables were examined during a perturbation
study of USP dissolution Apparatus 2 using USP Prednisone Reference Standard (RS) Tablets. A Design of Experiment
(1) approach was used to screen the nine variables to determine the contribution of each, alone and in combination,

Introduction
Correlations between in vitro and in vivo data (IVIVC)
are often used during pharmaceutical development in
order to reduce development time and optimize the
formulation. A good correlation is a tool for predicting in
vivo results based on in vitro data. IVIVC allows dosage form
optimization with the fewest possible trials in man, fixes

Abstract
Efforts are being made by various groups (1,2) to focus more on mechanical calibration as a potential replacement for Prednisone
tablets RS (calibrator tablets). Although some mechanical calibration is currently performed (e.g.,wobble,centering),
the PhRMA committee’s original proposal was to replace the Prednisone tablets RS through use of enhanced mechanical calibration.

Question and Answer Section - August 2008

William Brown and Margareth Marques
The following questions have been submitted by readers of Dissolution Technologies. Margareth Marques, Ph. D. and Will Brown, United States Phamacopeia, authored responses to each of the questions.

Aworkshop on the Role of Dissolution in QbD and
Drug Product Life Cycle was held in Crystal City,
Virginia. This workshop was jointly sponsored by
U.S. Food and Drug Administration and AAPS. The
meeting audio tapes are available at http://www.
aapspharmaceutica.com/meetings/meeting.asp?id=126.
The theme of the entire workshop was the exploration

Dissolution studies have become matter of great significance because, in most cases, drug dissolution is the
rate-limiting step in the absorption process. As occurs with solid oral dosage forms, heterogeneous disperse systems
(suspensions) could also have some problems with their in vitro dissolution.

ABSTRACT
Solid dispersions traditionally have been used as effective methods to improve the dissolution properties and
bioavailability of poorly water-soluble drugs. The aim of the present study was to improve the solubility and dissolution
rate of a poorly water-soluble drug, furosemide, by a solid dispersion technique. Solid dispersions were prepared using

ABSTRACT
Dissolution methods are different for extended-release mesalamine capsules (pH 7.5 only) and delayed-release tablets
(pH 1.4, 6.0, and 7.2). Mesalamine is used for the treatment of ulcerative colitis. The USP methods have several drawbacks
in that they do not mimic gastrointestinal tract environments; tablets are removed from vessels to change dissolution

Question and Answer Section - May 2008

William Brown and Margareth Marques
The following questions have been submitted by readers of Dissolution Technologies. Margareth Marques, Ph. D. and Will Brown, United States Phamacopeia, authored responses to each of the questions.
*Note: These are opinions and interpretations of the authors, and are not necessarily the official viewpoints of the USP

ABSTRACT
The development of a meaningful dissolution procedure for drug products with limited water solubility has been a
challenge to the pharmaceutical industry. Aceclofenac (BCS Class II drug) is a nonsteroidal anti-inflammatory drug. There
is no official dissolution medium available in the literature. In the present study, parameters such as solubility, medium pH,