Saeed Qureshi

Saeed Qureshi
PharmacoMechanics

Ph.D.

About

55
Publications
38,684
Reads
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935
Citations
Citations since 2017
2 Research Items
211 Citations
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Introduction
Extensive (30 years) experience in conducting hands-on and multi-disciplinary laboratory research. Expertise: Pharmacokinetics, biopharmaceutics, drug dissolution testing, analytical chemistry as related to characterization of pharmaceuticals, in particular based on in vitro (dissolution) and bioavailability/bioequivalence (humans and animals) assessments; Thorough knowledge and understanding of various concepts (e.g. SUPAC, BCS, IVIVC, QbD) and standards and guidelines (e.g. FDA, USP, ICH).
Additional affiliations
June 2015 - present
Pharmacomechanics
Position
  • Head of Faculty
Description
  • Dr. Qureshi provides teaching, training and consulting services, in the area of his expertise as noted above, for improved pharmaceutical products development and assessments. Dr. Qureshi can be reached by email (principal@pharmacomechanics.com) or Tel (+1 613 797 9815)
May 1985 - May 2015
Health Canada
Position
  • Senior Researcher

Publications

Publications (55)
Chapter
The term quality of pharmaceutical products is frequently used in the literature interchangeably with safety and efficacy without a clear description. The lack of clarity and relevant use of these terminologies appear not only to cause confusion, but currently they also seriously hinder the development and assessment of pharmaceutical products, suc...
Article
Full-text available
In principle, drug dissolution testing should be one of the simplest analytical techniques, however, in practice it is perhaps the most confusing, complex and frustrating techniques often lacking scientific and/or logical considerations. Perhaps the strange aspect of current practices is that despite the availability of hundreds, if not thousands,...
Article
Full-text available
Evaluating an IVIVC is a desirable feature for any drug dissolution test to establish relevance and confidence in assessing the quality and safety of solid oral dosage products, such as tablets and capsules. However, success in this area has been limited. One of the reasons for this lack of success may be that the approaches described in the litera...
Article
Current practices of drug dissolution testing require that the experimental conditions, such as medium and its volume and apparatus and its associated stirrer rotation speed, be established for each test product to achieve certain 'expected' dissolution characteristics or results. In reality, however, the purpose of dissolution testing should be to...
Article
Full-text available
Choice of a dissolution medium is an important and critical variant for drug dissolution testing. The reported choices range from a simple solvent (water) to complex solutions, often drug and/or product dependent. However, making a choice is not so simple or straightforward, but confusing and often scientifically or logically not convincing or vali...
Article
Abstract The drug release characteristics of three oral formulations (one conventional and 2 extended-release) of nifedipine were evaluated using a flow-through apparatus. The experiments were conducted for 4 to 24 hours using water or phosphate buffer (0.05 or 0.1 M; pH 7.4) with or without solubilizing agent, Tween, as a dissolution medium at a f...
Article
Abstract This report describes results of a survey conducted to assess the variability in drug release from the USP calibrators and its dependence on various deaeration methods. The calibrator data submitted by 33 laboratories, involved tests of 1659 sets (6 or 12 tablets/set) from four lots of prednisone and salicylic acid each, using apparatuses...
Article
Full-text available
Often the quality of drug products is evaluated based on chemical tests, commonly described in different phar-macopeias such as the USP. These tests includes: assay (potency), uniformity of dosage form and dissolution test. Presently , these tests are conducted separately with three procedures. Furthermore, dissolution tests are also conducted usin...
Article
Two approaches, referred commonly as mechanical and chemical calibrations, are generally described in the literature for the performance verification of dissolution apparatuses. There is an on going debate on the benefits and limitations of these two approaches. This article provides a discussion on the deficiencies of the current practices, which...
Article
Dissolution tests employed as quality assurance/control tests to monitor potential changes in product formulation and/or manufacturing attributes do not necessarily reflect drug releasecharacteristics in humans, i.e. they may lack bio-relevancy. In such cases, observed deviation from expected drug release (dissolution) characteristics, even with po...
Article
Full-text available
Drug dissolution profiles are increasingly used to evaluate drug release characteristics of pharmaceutical products. Discrimi- natory dissolution profiles are highly desirable for differentiating between products having differences in pharmaceutical attributes (formulation and/or manufacturing processes differences) that may reflect corresponding d...
Article
Full-text available
A new crescent-shaped spindle has been proposed to address artefacts found with the USP Paddle spindle. Because of improved stirring and mixing environment within dissolution vessels resulting in improved product-medium interactions, the crescent-shaped spindle provides a more appropriate dissolution test. Diltiazem immediate- (IR) and extended-rel...
Article
Recently a new crescent-shaped spindle has been proposed to address the issues related to poor hydrodynamics of the USP paddle apparatus and its associated artifacts of high variability and lack of bio-relevant results. For improved comparison of drug dissolution characterization, it is highly desirable to conduct testing using common experimental...
Article
Drug release characteristics of two amoxicillin capsule products, 250 and 500 mg strength each, have been described using USP Paddle and crescent-shaped spindles. Using the same spindles, dissolution experiments were conducted with USP disintegrating (prednisone) and non-disintegrating (salicylic acid) calibrator tablets. Dissolution tests were con...
Article
A crescent spindle (patent pending) is described which may be used in place of the USP paddle component in USP dissolution apparatus 2. The new spindle is curve shaped, corresponding to the bottom of a dissolution vessel, with attached bristles to fill in the gap between the spindle and the surface of the vessel. The geometry of the new spindle pro...
Article
Considering a variable mixing/stirring and flow pattern in a drug dissolution vessel as a likely source of high variability in results, experiments were conducted using USP paddle apparatus by placing (aligned to the walls) a metal strip (1.7 mm thickx6.4 mm wide) in a dissolution vessel. The metal strip forces the undisintegrated tablet to settle...
Article
To evaluate variability in drug dissolution testing 28 laboratories analyzed USP calibrators, US FDA prednisone tablets and a marketed glibenclamide tablet product. The experiments were conducted using paddle and basket methods at 50 (calibrators) and 75 (glibenclamide) rpm. The media employed were deaerated by equilibrating at 37 degrees C for 24...
Article
Unlabelled: The percutaneous absorption studies were performed using a flow-through diffusion cell system with skin specimens from 24 healthy women to assess the penetration of glycolic acid (GA). Percentages of GA, based on 14C-labelled activity, found in the skin after application of 4% GA at pH 2.0 or pH 3.8, after 24 h were as follows: stratum...
Article
This report describes results of a collaborative study in which samples of the 40-mg strength of furosemide tablets were evaluated following a common protocol based on British (BP), European (Ph. Eur.), and US Pharmacopoeial (USP) specifications. Several tests, including identification, uniformity of mass, and dissolution, were performed. In total,...
Article
Full-text available
To evaluate the use of a flow-through diffusion cell system to assess the absorption and penetration characteristics of drug (acyclovir) products. In vitro studies were performed to assess the absorption/penetration of acyclovir using a flow-through diffusion cell system with human skin sections obtained from 19 healthy women following mammoplasty....
Article
In 1981 FIP published Guidelines for Dissolution Testing of Solid Oral Products us a joint report oj the Section for Official Laboratories and Medicines Control Services and the Section of Industrial Pharmacists. These guidelines were intended as suggestions primarily directed to compendial committees, working on the introduction ofdissolution/rele...
Article
An HPLC method for the quantification of ketoprofen enantiomers in human plasma is described. Following extraction with a disposable C18 solid-phase extraction column, separation of ketoprofen enantiomers and I.S. (3,4-dimethoxy benzoic acid) was achieved using a chiral column [Chirex 3005; (R)-1-naphthylglycine 3,5-dinitrobenzoic acid] with the mo...
Article
Full-text available
This report summarizes some trends observed in drug dissolution testing, based upon the United States Pharmacopeia (USP) dissolution Apparatus Suitability Test results and the preliminary data obtained from an international collaborative study to assess the pharmaceutical quality of furosemide products in different countries. Based on the USP calib...
Article
This report describes results of a collaborative study in which samples of the 5 mg strength of prednisone tablets were evaluated following a common protocol based on European (Ph. Eur.) and US Pharmacopeial (USP) specifications. Several tests including, identification, content uniformity and dissolution were performed. Laboratories from 16 countri...
Article
Pharmacokinetic and pharmacodynamic interactions of alcohol and nifedipine were assessed in 10 healthy human volunteers. Doses of 20 mg (2 × 10-mg capsules) of nifedipine were administered with either 150 ml of orange juice or 75 ml of alcohol (94%) in 75 ml of orange juice according to a crossover randomized design. Plasma nifedipine levels were m...
Article
The nephrotoxicity of the anti-manic-depressive drug lithium (Li) is well recognized but the effects of fluctuation in plasma levels from different Li dosage regimens are not. Experiments were done to compare the nephrotoxicity of Li in rats treated either with subcutaneous multiple injections (SMI) or by infusion using mini-osmotic pumps (MOP) vs...
Article
To the Editor.— We wish to report an interaction of oral nifedipine with acute alcohol ingestion.Study— Ten healthy, male volunteers were recruited, prescreened, and the study completed according to Canadian Medical Research Council guidelines for clinical studies. Following an overnight fast volunteers were randomized in a cross-over design to r...
Article
A high-performance liquid chromatographic (HPLC) method for the determination of individual B6 vitamers was developed, and its application to dog, rat, monkey and human serum is described. Serum samples were deproteinated with 8% aqueous perchloric acid and the extracts were purified using an anion-exchange column. Analytical separation of the B6 v...
Article
1. The concentrations of propranolol (PPL) and its metabolites were monitored by h.p.l.c. in serum of rats during the first 6 h after administering single doses (20 mg/kg) of PPL either orally or intravaginally (i.vg). 2. The results showed that PPL was quickly transferred to the systemic circulation from the rat vagina and the serum concentration...
Article
1. Incubations of racemic propranolol alone or in the presence of either quinidine or sparteine were performed with Cunninghamella bainieri. 2. Five mammalian metabolites of propranolol (4-hydroxypropranolol, desisopropyl-propranolol, 1-naphthoxylactic acid, propranolol glycol and 1-naphthoxyacetic acid) were present in unhydrolysed extracts of the...
Article
Full-text available
Using a recently suggested approach, based on IVIVC principles, C-t profiles (or blood levels) are determined for different strengths and release types (IR and ER) of carbamazepine products from in vitro drug dissolution results. Drug dissolution tests were conducted using the crescent-shaped spindle (25 rpm) with 900 mL of water containing 0.5% of...

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