Sudhakar Garad

Developability Assessment in Pharmaceutical Industry: An Integrated Group Approach for Selecting Developable Candidates

This article describes the role and responsibilities of the Developability Assessment Group (DAG), a pharmaceutical Research and Development (R&D) subgroup, which supports drug discovery and development scientists with screening, developability assessment, and selection of new molecular entities (NMEs) for clinical studies. A strong collaboration between discovery group and DAG is essential for selecting the right NMEs for late-stage development, and consequently decreasing the NME attrition rate in late-stage development as well as in bringing down the associated cost and timelines. The investigations performed by DAG for evaluating research leads as well as the significance of these investigations in the developability assessment, the value of cutting edge tools and technologies, and the usefulness of the data in the decision making process are discussed in this review. Developability assessment of NMEs often includes physicochemical and biopharmaceutical characterization, development of suitable formulations for pharmacokinetic (PK), efficacy, and toxicity studies, selection of suitable physical form (salt, polymorph, etc.), and formulation development for phase I clinical studies. Overall DAG activities not only contribute to streamlining efficacy-toxicology evaluation, but also in building developability screens, which allow pharmacologically effective, minimally toxic, and developable candidates to reach the clinic and eventually to the market.

Selection of oral bioavailability enhancing formulations during drug discovery

The objective of this paper was to identify oral bioavailability enhancing approaches for a poorly water-soluble research compound during drug discovery stages using minimal amounts of material. LCQ789 is a pBCS (preclinical BCS) Class II compound with extremely low aqueous solubility (<1 µg/mL) and high permeability, therefore, resulting in very low oral bioavailability in preclinical species (rats and dogs). A number of solubility and/or dissolution enhancing approaches including particle size reduction, solid dispersions, lipid-based formulations and co-crystals, were considered in order to improve the compound’s oral bioavailability. High-Throughput Screening (HTS) and in silico modeling (GastroPlus™) were utilized to minimize the compound consumption in early discovery stages. In vivo evaluation of selected physical form and formulation strategies was performed in rats and dogs. Amongst the formulation strategies, optimized solid dispersion and lipid-based formulation provided significant improvement in drug dissolution rate and hence, oral bioavailability. In addition, a significant impact of physical form on oral bioavailability of LCQ789 was observed. In conclusion, a thorough understanding of not only the formulation technique but also the physical form of research compounds is critical to ensure physical stability, successful pharmacokinetic (PK) profiling and early developability risk assessment.

Preclinical Development for Suspensions

This chapter summarizes the significance of suspension in preclinical development. Majority of the preclinical studies are carried out using suspension. Therefore, it is important to know the physical form change, particle size distribution, ease of manufacturability and physico-chemical stability for the molecules used in preclinical studies. Here, the impact of physicochemical properties and formulation on the oral exposure in vivo and toxicity of drug candidates were reviewed in line with other ADME parameters (absorption, distribution, metabolism and elimination). From drug discovery perspective, the latest development of in vitro and in vivo approaches and the opportunity/limitation to assess the potential risks of drug candidates are summarized. Strategy to apply multiple ADME and formulation tools in lead optimization and candidate selection in drug discovery were also demonstrated. Authors focused more on oral suspension, however, there are a number of other dosage forms where suspension can be applied such as topical, parenteral, and inhalation.

Co-crystal formation based on structural matching.

A co-crystal is defined as a single crystalline structure composed of two or more components with no proton transfer which are solid at room temperature. Our group has come up with the following rationale selection of co-formers for initial co-crystal screening: 1) selection of co-formers with the highest potential for hydrogen bonding with the API and 2) selection of co-formers with diversity of secondary structural characteristics. We demonstrate the feasibility of this technique with a Novartis drug candidate A. In the first tier, 20 co-formers were screened and two hits were identified. By examining the two co-formers, which worked from the first round, a second round of screening was undertaken with more focused chemical matter. Nineteen co-crystal formers closely related to the two hits in the first screen were screened in the second tier. From this screen five hits were identified. All the hits were compared for their physical and chemical stability and dissolution profile. Based on the comparison 4-aminobenzoic co-crystal was chosen for in-vivo comparison with the free form. The co-crystal had 12 times higher exposure than the free form thus overcoming the solubility limited exposure.