Adil Mohammad

Chemometric Model Development and Comparison of Raman and 13C Solid-State Nuclear Magnetic Resonance–Chemometric Methods for Quantification of Crystalline/Amorphous Warfarin Sodium Fraction in the Formulations

Warfarin sodium (WS) exists in multiple solid-state forms. The solid-state forms differ in physicochemical properties, and crystalline changes in the drug formulation may influence on the drug product quality and/or clinical performance. It is, therefore, critically important to have a good and reliable analytical method to monitor and quantitate this transformation during stability studies. The aim of the present research was to investigate Raman spectroscopy and solid-state nuclear magnetic resonance ((13)C ssNMR) methods in conjunction with chemometry to quantitate the amorphous and crystalline WS fractions in the drug products. Compositionally identical formulations of amorphous and crystalline WS were prepared, and mixed in various proportions to make 0%-100% amorphous/crystalline sample matrices. Raman and (13)C ssNMR spectra were collected and subjected to partial-least-squares and principle component regressions after mathematical treatment of the data. The model performance parameters such as root-mean-square error of prediction, standard error of prediction, and bias were low for Raman models in comparison to (13)C ssNMR models. Models predicted values of the independent sample matrices match closely with the actual values at high level of crystalline WS. Thus, the developed methods provide means to control and quantitate the WS forms fraction in the drug product.

Long-term stability study of Prussian blue – A quality assessment of water content and thallium binding

The purpose of this study is to assess the long-term stability of Prussian blue (PB) drug product (DP) and active pharmaceutical ingredient (API) under laboratory storage conditions by monitoring the loss in water content and the corresponding change of the in vitro thallium binding capacity that represents product performance. The bound water content and the in vitro thallium binding capacity of PB DPs and APIs were measured in 2003 and 2013, respectively. Water content, a critical quality attribute that directly correlates to the thallium (Tl) binding capacity was measured by thermal gravimetric analysis (TGA). The thallium binding study was conducted by testing PB in buffered solutions over the human gastrointestinal pH range with thallium concentrations ranging from 600 to 1,500 ppm. Samples were incubated at physiological temperature of 37°C in a shaking water bath to mimic gastric flux and intestinal transport. The binding equilibrium was reached at 24h. Following incubation, each sample was filtered and the free thallium was analyzed using a validated inductively coupled plasma spectroscopic method (ICP). The Langmuir isotherm was plotted to calculate maximum binding capacity (MBC). Compared with 2003, the water content of DP-1 decreased by about 14.1% (from 15.6 to 13.4 mol), and the MBC of DP-1 decreased by about 12.5% (from 714 to 625 mg/g) at pH 7.5. When low concentration of thallium (600 ppm) was used at pH 7.5, the Tl binding remained comparable for both API-1 (286 vs 276 mg/g) and DP-1 (286 vs 268 mg/g). Similarly, the Tl binding remained unchanged for both API-1 (237 vs 255 mg/g) and DP-1 (234 vs 236 mg/g) at pH 5.0. However, at pH 1.0 the binding was reduced 32.3% and 25.9% for API-1 and DP-1, respectively. Since the majority of binding takes place in the upper GI tract where pH around 5 can be expected, and therefore, the Tl binding capacity of PB should be comparable for new and aged samples. The findings that Tl binding changes with the water loss of PB and pH conditions are consistent with our previously published data. The study also represents the first quantitative assessment of the long-term stability of PB. Over last 10 years, PB DPs and APIs have lost about 20% water under ambient laboratory storage conditions which are consistent with a controlled warehouse environment. While the maximum binding capacity of PB to thallium was decreased after about 10 years of long-term storage, it is still very effective, suggesting that the shelf life of PB should be much longer than the manufacturer ascribed expiration date of 2008 under proper storage conditions.

Impact of formulation and process variables on solid-state stability of theophylline in controlled release formulations.

Understanding the impact of pharmaceutical processing, formulation excipients and their interactions on the solid-state transitions of pharmaceutical solids during use and in storage is critical in ensuring consistent product performance. This study reports the effect of polymer viscosity, diluent type, granulation and granulating fluid (water and isopropanol) on the pseudopolymorphic transition of theophylline anhydrous (THA) in controlled release formulations as well as the implications of this transition on critical quality attributes of the tablets. Accordingly, 12 formulations were prepared using a full factorial screening design and monitored over a 3 month period at 40 °C and 75%. Physicochemical characterization revealed a drastic drop in tablet hardness accompanied by a very significant increase in moisture content and swelling of all formulations. Spectroscopic analysis (ssNMR, Raman, NIR and PXRD) indicated conversion of THA to theophylline monohydrate (TMO) in all formulations prepared by aqueous wet granulation in as early as two weeks. Although all freshly prepared formulations contained THA, the hydration-dehydration process induced during aqueous wet granulation hastened the pseudopolymorphic conversion of theophylline during storage through a cascade of events. On the other hand, no solid state transformation was observed in directly compressed formulations and formulations in which isopropanol was employed as a granulating fluid even after the twelve weeks study period. The transition of THA to TMO resulted in a decrease in dissolution while an increase in dissolution was observed in directly compressed and IPA granulated formulation. Consequently, the impact of pseudopolymorphic transition of theophylline on dissolution in controlled release formulations may be the net result of two opposing factors: swelling and softening of the tablets which tend to favor an increase in drug dissolution and hydration of theophylline which decreases the drug dissolution.

Long-term stability study of Prussian blue—A quality assessment of water content and cyanide release

Abstract Context. Prussian blue, ferric hexacyanoferrate is approved for (oral) treatment of internal contamination with radioisotopes of cesium or thallium. Cyanide makes up 35–40% of Prussian blues molecular composition; thus, cyanide may be released during transit through the digestive tract under physiological pH conditions. Objectives. The purpose of this study is to assess the long-term stability of Prussian blue drug products and active pharmaceutical ingredients and its impact on cyanide release. The study involves the determination and comparison of the loss in water content and cyanide released from Prussian blue under pH conditions that bracket human physiological exposure. Methods. Test samples of active pharmaceutical ingredient and drug product were stored for 10 years at ambient temperatures that mimic warehouse storage conditions. Water loss from Prussian blue was measured using thermogravimetric analysis. An in vitro physiological pH model that brackets gastric exposure and gastrointestinal transit was utilized for cyanide release. Prussian blue was incubated in situ at pH: 1.0, 5.0, and 7.0 @ 37°C for 1–24 h. Cyanide was measured using a validated colorimetric method by UV–Vis spectroscopy. Results. Although the water content (quality attribute) of Prussian blue active pharmaceutical ingredient and drug product decreased by about 10.5% and 13.8%, respectively, since 2003, the cyanide release remained comparable. At pH of 7.0 for 24 h cyanide released from active pharmaceutical ingredient-1 was 21.33 ± 1.76 μg/g in 2004, and 28.45 ± 3.15 μg/g in 2013; cyanide released from drug product-1 was 21.89 ± 0.56 μg/g in 2004, and 27.31 ± 5.78 μg/g in 2013. At gastric pH of 1.0 and upper gastrointestinal pH of 5.0, the data for active pharmaceutical ingredients and drug products were also comparable in 2013. The cyanide release is still pH-dependent and follows the same trend as observed in 2003 with minimum release at pH of 5.0 and maximal release at pH of 1.0. In summary, this is the long-term stability study of Prussian blue which correlates cyanide release to water loss. Cyanide released from Prussian blue was maximum at pH of 1.0 (47.47 μg/g) and minimum at pH of 5.0–7.0 (20.01 μg/g). Conclusions. Based on maximal dose, maximal residence time in stomach and intestine, the maximal cyanide released from Prussian blue is about 1.31 mg, which is far below the minimal lethal dose of cyanide of 50 mg, and therefore does not present a safety concern following long-term storage.

Leachable diphenylguanidine from rubber closures used in pre-filled syringes: A case study to understand solid and solution interactions with oxytocin.

Leachables derived from multi-component drug-device syringe systems can result in changes to the quality of drug products. Diphenylguanidine (DPG), a leachable released from styrene butadiene rubber syringe plungers, interacts with Oxytocin to form protein-adducts. This study investigated the mechanism and kinetics of this interaction in both solid and solution states through in-vitro tests and spectroscopic methods For solid state interaction, the protein-adducts with DPG were characterized using SEM, XRD, DSC, FTIR, 13C ss NMR, and dissolution analysis. For solution state interaction, LC-HRMS was used to assess stability of Oxytocin solutions in presence of various concentrations of DPG at 25°C and 40°C for 4 weeks. Moreover, molecular docking analysis was used to identify possible molecular configurations of the interaction.Results were consistent with the formation of a new solid state with distorted surface morphology for oxytocin-DPG adducts, in which the oxytocin carbonyl group(s) and the secondary amine groups of DPG interact. This interaction was also confirmed by molecular docking analysis through hydrogen bonding (2.31Å) and Van der Waal attraction (3.14Å). Moreover, LC-HRMS analysis revealed an increase in Oxytocin stability and suppression of Oxytocin dimerization by DPG. A potential reduction in the rate of Oxytocin dissolution from the formed adducts was indicative of its strong association with DPG. Hence, the leaching potential of DPG from rubber closures and plungers should be monitored and controlled to maintain the quality and stability of the pharmaceutical product.

An ICP-MS platform for metal content assessment of cell culture media and evaluation of spikes in metal concentration on the quality of an IgG3:κ monoclonal antibody during production

&NA; Metal ions can be enzyme cofactors and can directly influence the kinetics of biochemical reactions that also influence the biological production and quality attributes of therapeutic proteins, such as glycan formation and distribution. However, the concentrations of metals in commercially available chemically defined media can range from 1 to 25,000 ppb. Because such concentration changes can impact cell growth, manufacturing yield and product quality the alteration/fluctuation in media composition should be well controlled to maintain product quality. Here, we describe a platform of analytical methods to determine the composition of several metals in different sample matrices using an advanced automated Inductively Coupled Plasma‐Mass Spectrometry (ICP‐MS). These methods, validated to ICH Q2R1 regulatory validation parameters, were successfully applied to‐ (a) screen cell culture media; (b) determine changes in the metal concentration during cell growth in spinner flasks, and, (c) determine effect on the glycosylation pattern and homogeneity of an IgG3:&kgr; produced from a murine‐hybridoma cell line in bench‐top parallel bioreactors due to a spike in copper and iron concentration. Our results show that maintenance of metal content in the cell culture media is critical for product consistency of the IgG3:&kgr; produced. HighlightsAn ICP‐MS methodology to determine bulk, minor and trace metal content (0.05 ppb–500 ppb) of mammalian cell culture media.An advanced autodilution platform for autocalibration and quality control to enhance throughput.Application of this method to demonstrate the affected homogeneity of a model therapeutic due to spikes in the concentration of copper and iron in parallel bioreactors.