Stability parameter estimation at ambient temperature from studies at elevated temperatures

Design of a Reciprocal Injection Device for Stability Studies of Parenteral Biological Drug Products

Formulation screening, essential for assessing the impact of physical, chemical, and mechanical stresses on protein stability, plays a critical role in biologics drug product development. This research introduces a Reciprocal Injection Device (RID) designed to accelerate formulation screening by probing protein stability under intensified stress conditions within prefilled syringes. This versatile device is designed to accommodate a broad spectrum of injection parameters and diverse syringe dimensions. A commercial drug product was employed as a model monoclonal antibody formulation. Our findings effectively highlight the efficacy of the RID in assessing concentration-dependent protein stability. This device exhibits significant potential to amplify the influences of interfacial interactions, such as those with buffer salts, excipients, air, metals, and silicone oils, commonly found in combination drug products, and to evaluate the protein stability under varied stresses.

Determining shelf life by comparing degradations at elevated temperatures

The degradation of a biological product follows a specific pattern that depends on the kinetics of the chemical reaction. For most biological and pharmaceutical products, accelerated stability tests are preferred to establish shelf life. We describe a new approach for accelerated stability tests, for situations in which the Arrhenius equation is not appropriate. This approach consists of estimating stability at elevated temperatures and comparing these results with the stability estimates for a similar product with a known shelf life. In this article, "Test" refers to Immuno-Trol Low Cells, and "Control" (the product with a known shelf life) refers to Immuno-Trol Cells. The degradation rates and stabilities at elevated temperatures of three antigens of the Test are estimated and compared to their respective Control values. Most of the degradation occurs at the beginning of the experimental period and then slows down until it levels off to form a plateau at the minimum level. Both Control and Test showed similar degradation patterns at three elevated temperatures, indicating that they both have the same mechanism of degradation. Thus, it is expected that they will degrade similarly at storage temperature and have nonsignificantly different shelf lives. The approach for accelerated stability testing discussed here is applicable to situations in which the Arrhenius equation is not appropriate, and the chemical properties of both the Test and Control products are similar.

On the hydrolytic behavior of tinidazole, metronidazole, and ornidazole

Using two UV-spectrophotometric methods, the hydrolysis of tinidazole was studied at pH 1.00-8.45 at 80 degrees C. The reaction followed apparent first-order kinetics throughout the studied range. No kinetic salt effect was detected, indicating that at least one of the reacting partners forming the transition state has a charge of 0. The reaction rate macro constants M(1)-M(4) were calculated to be 3.35 x 10(-2) M(-1) h(-1), 1.45 x 10(-2) h(-1), 3.76 x 10(-6) M h(-1), and 2.85 x 10(-11) M(2) h(-1), respectively. At pH >or= 7, the uncharged tinidazole was decomposed by the hydroxide ion; the reaction was found out to involve a proton transfer from the ethylsulfonylethyl side chain. At around pH 4.5, the degradation of the uncharged tinidazole was due to the solvent. In more acidic conditions, the reaction mechanism could not be fully resolved. The alkaline hydrolysis of metronidazole was studied on the basis of literature data. A general reaction mechanism was proposed, but an unequivocal explanation for the inflection point in the pH rate profile at pH 6 could not be found. The implications of the proposed reaction mechanism for the hydrolytic behavior of ornidazole were discussed.