ABSTRACT
The acyloxyalkyl derivatives of a model anti-HBV dinucleotide were synthesized and evaluated as orally bioavailable prodrugs. Our studies have led to the identification of the first orally bioavailable dinucleotide prodrugs for further therapeutic development against the hepatitis B virus (HBV).
Subject(s)
Antiviral Agents/chemistry , Hepatitis B virus/genetics , Hepatitis B/drug therapy , Nucleotides/chemistry , Prodrugs/chemistry , Administration, Oral , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/therapeutic use , Cell Line , Female , Humans , Male , Mice , Mice, Transgenic , Mutation , Nucleotides/chemical synthesis , Nucleotides/therapeutic use , Prodrugs/chemical synthesis , Prodrugs/therapeutic use , Rats , Rats, Sprague-DawleyABSTRACT
PURPOSE: The aim of the study is to solve a significant challenge of extending the half-life of therapeutic proteins using crystalline biopharmaceuticals and without redesigning the molecules. METHODS: Crystals of recombinant human growth hormone were coated with a monomolecular layer of positively charged poly(arginine). The pharmacokinetics and pharmacodynamics of this poly(arginine)-coated human growth hormone crystalline formulation were determined in hypophysectomized rats and monkeys. RESULTS: Here we have demonstrated for the first time that crystals of human growth hormone coated with positively charged poly(arginine) allowed for in vivo pharmacokinetic release profiles of over several days in animal models. The efficacy of this crystalline formulation injected subcutaneously once a week was found to be equivalent to seven daily soluble injections in the standard weight gain assay using the hypophysectomized rat model and in measurement of serum insulin-like growth factor in monkeys. The nonviscous nature of the suspension facilitated easy administration through a fine, 30-gauge needle and should provide for improved patient convenience and compliance. CONCLUSIONS: The approach described here offers an exciting possibility of being broadly applicable to other therapeutic proteins.
Subject(s)
Chemistry, Pharmaceutical , Human Growth Hormone/chemistry , Adsorption , Animals , Crystallization , Female , Human Growth Hormone/pharmacokinetics , Human Growth Hormone/pharmacology , Humans , Macaca fascicularis , Microscopy, Electron, Scanning , Models, Animal , Peptide Mapping , Peptides/chemistry , Rats , Rats, Sprague-Dawley , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacokinetics , Recombinant Proteins/pharmacology , Spectroscopy, Fourier Transform Infrared , ThermodynamicsABSTRACT
The year 2002 marked the 20th anniversary of the first successful product of modern biotechnology, the regulatory approval of recombinant insulin for biopharmaceutical applications. Insulin is also the first crystalline protein to be approved for therapeutic use. Over the past two decades, almost 150 biopharmaceuticals have gained marketing authorisation; however, insulin remains the only crystalline protein on the market. Significant research and development efforts have focused on the engineering of protein molecules, efficacy testing, model development, and protein production and characterisation. These advances have dramatically boosted the therapeutic applications of proteins, which now include treatments against acute conditions, such as cancer, cardiovascular disease and viral disease, and chronic conditions, such as diabetes, growth hormone deficiency, haemophilia, arthritis, psoriasis and Crohn's disease. Despite these successes, many challenges normally associated with biopharmaceuticals, such as poor stability and limited delivery options, remain. Protein crystals have shown significant benefits in the delivery of biopharmaceuticals to achieve high concentration, low viscosity formulation and controlled release protein delivery. This review will discuss challenges related to the broader utilisation of protein crystals in biopharmaceutical applications, as well as recent advances and valuable new directions that protein crystallisation-based technologies present.
