Neuronal nicotinic ␣7 acetylcholine receptors (␣7nAChRs) are expressed primarily in the brain and are implicated in modulating many cognitive functions (e.g., attention, working and episodic memory). Not surprisingly, much effort has been committed to the development of molecules acting at ␣7nAChRs as potential therapies for a variety of central nervous system diseases (e.g., Alzheimer's).
N-[(3S)-1-azabicyclo[2.2.2]oct-3-yl]-1H-indazole-3-carboxamide hydrochloride (RG3487) binds potently to the human ␣7nAChR (K i ϭ 6 nM), in which it acts as a partial agonist (63-69% of acetylcholine) as assessed by whole-cell patch-clamp recordings in both oocytes and QM7 cell lines. RG3487 activates human ␣7nAChRs with an EC 50 of 0.8 M (oocytes) and 7.7 M (QM7 cells). RG3487 also exhibits antagonist properties at the serotonin 3 receptor [IC 50 ϭ 2.8 nM (oocytes), 32.7 nM (N1E-115 cells)]. In vivo, RG3487 improved object recognition memory in rats after acute [minimally effective dose (MED) 1.0 mg/kg p.o.] or repeated (10 day) administration at brain and plasma concentrations in the low-nanomolar range. Spatial learning deficits in age-impaired rats were reversed after RG3487 administration (MED: 0.03 mg/kg i.p.) as evaluated in the Morris water maze task. In the prepulse inhibition (PPI) of startle model of sensorimotor gating, RG3487 improved apomorphine-induced deficits in PPI performance (MED: 0.03 mg/kg i.p.) and reversed phencyclidine-induced impairments in an attentional set-shifting model of executive function (MED: Յ0.03 mg/kg i.p.). Cumulative evidence from these studies indicates RG3487 is a novel and potent ␣7nAChR partial agonist that improves cognitive performance and sensorimotor gating.
As outlined in the ICH Q8(R2) guidance, identifying the critical quality attributes (CQA) is a crucial part of dosage form development; however, the number of possible formulation and processing factors that could influence the manufacturing of a pharmaceutical dosage form is enormous obviating formal study of all possible parameters and their interactions. Thus, the objective of this study is to examine how quality risk management can be used to prioritize the number of experiments needed to identify the CQA, while still maintaining an acceptable product risk profile. To conduct the study, immediate-release ciprofloxacin tablets manufactured via roller compaction were used as a prototype system. Granules were manufactured using an Alexanderwerk WP120 roller compactor and tablets were compressed on a Stokes B2 tablet press. In the early stages of development, prior knowledge was systematically incorporated into the risk assessment using failure mode and effect analysis (FMEA). The factors identified using FMEA were then followed by a quantitative assessed using a Plackett-Burman screening design. Results show that by using prior experience, literature data, and preformulation data the number of experiments could be reduced to an acceptable level, and the use of FMEA and screening designs such as the Plackett Burman can rationally guide the process of reducing the number experiments to a manageable level.
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