PubMed · 14123659
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M R ERSKINE. 1964. LABORATORY PURCHASING.. https://pubmed.ncbi.nlm.nih.gov/14123659/
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New medical technologies generally must receive clearance or approval for marketing by the US Food and Drug Administration and be covered by an insurer, such as the Centers for Medicare and Medicaid Services, before becoming available for widespread clinical use. These 2 approval processes are discrete and usually occur sequentially rather than collaboratively and simultaneously. To explore potential mechanisms for increasing regulatory collaboration between these 2 key health care agencies, the Duke Clinical Research Institute and Health Strategies Consultancy convened an informal meeting of agency, academic, and industry leaders on December 8 and 9, 2002, titled "Registration/Approval and Coverage/Payment: Exploring Options for Improving Healthcare." This article arises from the discussion at this conference; it does not represent the official views of any person or institution involved. Although the group did not attempt to reach a consensus, it examined several important issues surrounding this regulatory debate. Herein are proposed options for enhancing regulatory efficiency through greater coordination between the FDA and CMS, and discussion of these proposals from the perspectives of members of both agencies, members of stakeholder organizations, and academic observers.
This review presents a critical analysis of covalently and ionically crosslinked chitosan hydrogels and related networks for medical or pharmaceutical applications. The structural basis of these hydrogels is discussed with reference to the specific chemical interactions, which dictate gel formation. The synthesis and chemistry of these hydrogels is discussed using specific pharmaceutical examples. Covalent crosslinking leads to formation of hydrogels with a permanent network structure, since irreversible chemical links are formed. This type of linkage allows absorption of water and/or bioactive compounds without dissolution and permits drug release by diffusion. pH-controlled drug delivery is made possible by the addition of another polymer. Ionically crosslinked hydrogels are generally considered as biocompatible and well-tolerated. Their non-permanent network is formed by reversible links. Ionically crosslinked chitosan hydrogels exhibit a higher swelling sensitivity to pH changes compared to covalently crosslinked chitosan hydrogels. This extends their potential application, since dissolution can occur in extreme acidic or basic pH conditions.