Synthesis of 3-O-Carboxyalkyl Morphine Derivatives and Characterization of Their Acid-Base Properties

Comparison of Orthogonal Determination Methods of Acid/Base Constants with Meta-Analysis

The accurate determination of acid/base constants (proton dissociation constants-pKa, or equivalently protonation constants-logK) is essential for the physicochemical characterization of new molecules, especially in drug design and development, as these parameters thoroughly influence the pharmacokinetics and pharmacodynamics of drug action. While pH/potentiometric titration remains the gold standard method for determining acid/base constants, spectroscopic techniques-particularly nuclear magnetic resonance spectroscopy (as NMR/pH titrations)-have emerged as powerful alternatives for specific challenges in analytical chemistry, providing also information on the structure and site of protonation. In this study, we performed a comprehensive meta-analysis of protonation constants reported in the literature, measured using both potentiometry and NMR titrations. Our analysis compiled the available literature data and assessed the agreement between the two methods, taking into consideration various experimental conditions, such as temperature and ionic strength. The results provide insights into the reliability and applicability of NMR titrations compared with potentiometry, offering guidance for selecting appropriate methodologies in drug design.

Opioid-Based Haptens: Development of Immunotherapy

Over the past decades, extensive preclinical research has been conducted to develop vaccinations to protect against substance use disorder caused by opioids, nicotine, cocaine, and designer drugs. Morphine or fentanyl derivatives are small molecules, and these compounds are not immunogenic, but when conjugated as haptens to a carrier protein will elicit the production of antibodies capable of reacting specifically with the unconjugated hapten or its parent compound. The position of the attachment in opioid haptens to the carrier protein will influence the specificity of the antiserum produced in immunized animals with the hapten-carrier conjugate. Immunoassays for the determination of opioid drugs are based on the ability of drugs to inhibit the reaction between drug-specific antibodies and the corresponding drug-carrier conjugate or the corresponding labelled hapten. Pharmacological studies of the hapten-carrier conjugates resulted in the development of vaccines for treating opioid use disorders (OUDs). Immunotherapy for opioid addiction includes the induction of anti-drug vaccines which are composed of a hapten, a carrier protein, and adjuvants. In this review we survey the design of opioid haptens, the development of the opioid radioimmunoassay, and the results of immunotherapy for OUDs.

Morphine alkaloids: History, biology, and synthesis

This chapter provides a short overview of the history of morphine since it's isolation by Sertürner in 1805. The biosynthesis of the title alkaloid as well as all total and formal syntheses of morphine and codeine published after 1996 are discussed in detail. The last section of this chapter provides a detailed overview of medicinally relevant derivatives of the title alkaloid.