Laboratory Testing Case Studies

Challenge: The prostacyclin derivative is a starting material in the manufacturing of a tricyclic benzidene prostacyclin analog with pharmacologic actions similar to those of Epoprostenol.  Epoprostenol improves exercise capacity and survival in patients with pulmonary arterial hypertension.  The prostacyclin analog is also efficacious by subcutaneous infusion, it is easier to administer and has a longer half-life.  Determination of this prostacyclin derivative and its impurities is central to developing a deep understanding of a commercial manufacturing process.

Challenge: The technological objective of this project was to investigate the peak purity of Ursodeoxycholic Acid drug substance and drug product with forced degradation by employing Ultra Performance Liquid Chromatography/Mass Spectrometry (UPLC/MS) techniques.  Ursodeoxycholic acid (UDCA) is one of the secondary bile acids, which are metabolic by-products of intestinal bacteria.  Essentially, Diteba was committed to investigate the degradation pathways and impurity profiles of Ursodeoxycholic Acid drug product by assessing the Ursodeoxycholic Acid peak purity by using a UPLC coupled with Mass Spectrometry (MS).

Challenge: The objective of this project at Diteba was to develop methods for complete compositional analysis of Krill Oil. Such characterization included total lipid / fat content, phospholipids, free fatty acids, triglycerides, cholesterol esters, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, lysophosphatidylcholine, sterols, cholesterol, sigmasterol, sigmastanol, sitosterol, vitamin D-3, vitamin E, and carotenoids: canthaxanthin, astaxanthin.

Challenge: A sensitive and specific bioanalytical method suitable for quantification of an immunomodulator compound in plasma matrix for human, rat and mouse samples at a low detection level, LLOQ = 10 pg/mL, was developed by Diteba's scientists for pre-clinical and clinical studies.  This compound is a member of a class of immunomodulatory drugs that possess γ-glutamyl or β-aspartyl moieties, which was discovered by Russian scientists and is being examined for efficacy in several indications.  The synthesized molecule contains two chiral centers and therefore can exist as four configurations: two enantiomers and two diastereoisomers.

Challenge: A sponsor had developed a promising group of "first in class" potent small molecule compounds for cancer therapy.  The research scientists and medicinal chemists used structure-based drug design to derive compounds that target important proteins and therapeutic pathways in cancer.  One of these candidates has shown to be a very potent, yet highly selective growth inhibitor of many cancer types, including non-small cell lung cancer, colon cancer and leukemia.

Challenge: Diteba was contracted to develop and validate a specific quantitative analytical method capable of simultaneously detecting and quantifying all three analytes (vitamers) in different biological fluids and support a clinical study as well as for toxicological studies on small animal models.  It should be noted that previously made attempts by a reputable US-based contract research organization to develop a suitable method for quantification of PLP, PL and 4-PA by Liquid Chromatographic Tandem Mass Spectrometry (LC/MS/MS) technique had failed due to the complexity of the project.  All three analytes appear at high endogenous levels in biological fluids which in turn complicates the analytical procedure.

Challenge: The goal of this project was to develop efficient analytical methods for complete compositional analysis of lipid-based drug candidates.  Analytical method requirements included extraction, separation, identification and quantification.  Such work would support development of formulations which would include a small amount of a well accepted non-medicinal ingredient commonly used in food and drug products.  This undertaking focused on the development of a full fatty acid profile analysis of new lipid-based drug candidates targeted to formulate advanced products related to High Density Lipoprotein (HDL), often called "good cholesterol".

Challenge: Diteba was contracted to develop and validate an appropriate analytical method capable of quantifying the levels of L-tryptophan (0.06 μmol/L to 222 μmol/L) and kynurenine (0.09 μmol/L to 9.84 μmol/L) in human serum.  Several HPLC methods have been developed over time to determine serum tryptophan and kynurenine.  However, none of this research has met desirable levels of sensitivity or reproducibility.  The methods described in the literature were complicated by the interference of other amino acids with the kynurenine UV absorption in HPLC chromatography.  In addition to the analytical method development and validation exercise, it was necessary to develop a simple and accurate method of extraction for tryptophan and kynurenine from patients' blood serum.  The extraction procedures were complicated because of the nature of the samples.  The patients' samples were infected with a chronic hepatitis C which required extreme precaution in drawing and handling these samples.

Challenge: Diteba's main objective of this study was to develop a simple, reliable and reproducible in vitro quality control method that could be used to discriminate variation in release characteristics of NNRTI solid dose formulations to assure batch-to-batch uniformity.  Diteba's scientists attempted to develop a methodology that could be used to discriminate formulation changes, and evaluate the precision, reproducibility and sensitivity for in vitro release rate study (IVRT) experiments.

1. Exhibiting linear pharmacokinetics, i.e., proportional to dose administrated from approximately 10 pg/mL to 5 000 pg/mL;
2. Assessing clinical studies conducted for a population of patients with inoperable chronic pulmonary hypertension (which are usually dosed 45-125 ng/kg/min); and
3. Proving that the synthetic prostacyclin analogue plasma concentrations remain linearly proportional to doses up to 125 ng/kg/min.

This compound is a long-acting analogue of prostacycline and it is administered in low doses (1.25-15 ng/kg/min) by continuous intravenous infusion to patients with pulmonary hypertension.  The drug improves survival and the hemodynamics in these patients.  However, the treatment is limited by a very short half-life (1-2 minutes) and chemical instability requiring continuous intravenous infusion and refrigeration during administration.  Some research has been published with regards to biotransformation and pharmacokinetics for Beraprost, a synthetic analog of prostacyclin.