A Rational Hierarchy to Capture Raw Material Attribute Variability in the Pharmaceutical Drug Product Development and Manufacturing Lifecycle.

Assessing the robustness of a drug product formulation and manufacturing process to variations in raw material (RM) properties is an essential aspect of pharmaceutical product development. Motivated by the need to demonstrate understanding of attribute-performance relationships at the time of new product registration and for subsequent process maintenance, we review practices to explore RM variations. We describe limitations that can arise when active ingredients and excipients invariably undergo changes during a drug product lifecycle. Historical approaches, such as Quality-by-Design (QbD) experiments, are useful for initial evaluations but can be inefficient and cumbersome to maintain once commercial manufacturing commences. The relatively miniscule data sets accessible in product development - used to predict response to a hypothetical risk of variation - become less relevant as real-world experience of actual variability in the commercial landscape grows. Based on our observations of development and manufacturing, we instead propose a holistic framework exploiting a hierarchy of RM variability, and challenge this with common failure modes. By explicitly incorporating higher ranking RM variations as perturbations, material-conserving experiments are shown to provide powerful and enduring robustness data. Case studies illustrate how correctly contextualizing such data in formulation and process development can avoid the traps of historical QbD approaches and become valuable for evaluating changes occurring later in the drug product lifecycle.

Detecting and Quantifying Microscale Chemical Reactions in Pharmaceutical Tablets by Stimulated Raman Scattering Microscopy.

It has been estimated that approximately 50% of all marketed drug molecules are manufactured and administered in the form of salts, often with the goal of improving solubility, dissolution rate, and efficacy of the drug. However, salt disproportionation during processing or storage is a common adverse effect in these formulations. Due to the heterogeneous nature of solid drug formulations, it is essential to characterize the drug substances noninvasively at micrometer resolution to understand the molecular mechanism of salt disproportionation. However, there is a lack of such capability with current characterization methods. In this study, we demonstrate that stimulated Raman scattering (SRS) microscopy can be used to provide sensitive and quantitative chemical imaging of the salt disproportionation reaction of pioglitazone hydrochloride (PIO-HCl) at a very low drug loading (1% w/w). Our findings illuminate a water mediated pathway of drug disproportionation and highlight the importance of noninvasive chemical imaging in a mechanistic study of solid-state chemical reactions.

Dispersive Raman Spectroscopy for Quantifying Amorphous Drug Content in Intact Tablets.

Process-induced inadvertent phase change of an active pharmaceutical ingredient in a drug product could impact chemical stability, physical stability, shelf life, and bioperformance. In this study, dispersive Raman spectroscopy is presented as an alternative method for the nondestructive, high-throughput, at-line quantification of amorphous conversion. A quantitative Raman method was developed using a multivariate partial least squares (PLS) regression calibration technique with solid-state nuclear magnetic resonance (ssNMR) spectroscopy as the reference method. Compositionally identical calibration tablets containing 20% w/w total MK-A drug in varying weight proportions (0%-50% w/w based on total MK-A) of amorphous and crystalline MK-A were compressed at 10-45 kN force. PLS predictions of amorphous content of tablets using Raman spectroscopy correlated well with ssNMR quantification. The predictive accuracy of this model led to a strong correlation (R2 = 0.987) with a root mean-squared error of prediction of 1.5% w/w amorphous MK-A in tablets up to 50% w/w amorphous conversion in compressive stress range of 60-320 MPa. Overall, these results suggest that dispersive Raman spectroscopy offers fast, sensitive, and high-throughput (<5 min/tablet) method for quantitating amorphous conversion.

Application of in vitro transmucosal permeability, dose number, and maximum absorbable dose for biopharmaceutics assessment during early drug development for intraoral delivery.

Intraoral (IO) administration is a unique route that takes advantage of transmucosal absorption in the oral cavity to deliver a drug substance locally or systemically. IO delivery can also enhance or enable oral administration, providing a better therapeutic benefit/safety risk profile for patient compliance. However, there are relatively few systematic biopharmaceutics assessments for IO delivery to date. Therefore, the goals of this study were to i) identify the most relevant in vitro permeability models as alternatives to porcine oral tissues (gold standard) for predicting human IO absorption and ii) establish guidelines for biopharmaceutics assessment during early drug development for IO delivery. Porcine kidney LLC-PK1 cells provided the strongest correlation of transmucosal permeability with porcine oral tissues followed by human Caco-2 cells. Furthermore, cultured human buccal tissues predicted high/low permeability classification and correlated well with porcine oral tissues, which are used for predicting clinical IO absorption. In the meantime, we introduced maximum absorbable dose and dose number in the oral cavity for IO delivery assessment as well as a decision tree to provide guidance for biopharmaceutics assessment during early drug development for IO delivery.

Release mechanisms of a sparingly water-soluble drug from controlled porosity-osmotic pump pellets using sulfobutylether-beta-cyclodextrin as both a solubilizing and osmotic agent.

The purpose of this work is to delineate the release mechanisms of a sparingly water-soluble drug, prednisolone (PDL), from a microporous or controlled porosity-osmotic pump pellet (CP-OPP) using sulfobutylether-beta-cyclodextrin (CD) as both a solubilizing and osmotic agent. All factors, osmotic and diffusional, influencing drug release as described by the Theeuwes and Zentner equation were partially demonstrated in an earlier paper1 and are further quantitatively evaluated here to determine whether the equation may be applied to CP-OPPs. The PDL release rate from the CP-OPPs containing precomplexed PDL follows the zero-order kinetics for up to 30-40% of drug release during the first 1-2 h and subsequently nonzero order kinetics. The zero-order drug release phase reveals the main contribution is from osmotic pumping with a negligible diffusion component, resulting from the nearly constant driving forces in the system. The nonzero order drug release phase is associated with the dynamic changes in the system (e.g., declining osmotic driving force and greater diffusion component with time). In addition, the parameters related to membrane characteristics were determined, and the effect of viscosity was evaluated for the pellet system. The membranes coated on the CP-OPPs are less permeable to water or solutes than the membranes coated on the previously reported tablets. The viscosity due to the CD decreases as a function of CD concentration, which partly affects the observed drug release profiles. The viscosity effect of CD is significant and captured in a hydraulic permeability term.

Controlled porosity-osmotic pump pellets of a poorly water-soluble drug using sulfobutylether-beta-cyclodextrin, (SBE) 7M-beta-CD, as a solubilizing and osmotic agent.

The objective of this work was to demonstrate that the incorporation of sulfobutylether-beta-cyclodextrin, (SBE)(7M)-beta-CD, results in the complete and sustained release of a sparingly water-soluble drug, prednisolone (PDL) from controlled porosity-osmotic pump pellets (CP-OPP). PDL and CD were prepared in various formulations (physical mixtures and presumed preformed complex). Several factors influencing drug and CD release were explored, and the probable mechanisms of drug release were probed and discussed. A significant improvement in the release of PDL from the CP-OPPs was observed by the incorporation of CD relative to the coated pellet formulation containing lactose in place of the CD. The release profiles of PDL depend on the molar ratio of CD to PDL, thickness of the microporous membrane, and osmotic pressure difference across the membrane. PDL appears to be released as an in situ complex with CD via mainly osmotic pumping during at least the initial portion of the release profiles.