Nazer Khalaf

Novel Long-Acting Crystal Formulation of Human Growth Hormone

PurposeThe 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.MethodsCrystals 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.ResultsHere 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.ConclusionsThe approach described here offers an exciting possibility of being broadly applicable to other therapeutic proteins.

Candida rugosa lipase: Enantioselectivity enhancements in organic solvents

Abstract Chiral resolutions of carboxylic acids ( 1–3 ) and alcohol ( 4 ) were carried out through esterification or transesterification in organic solvents using cross-linked enzyme crystals (CLEC®) of Candida rugosa lipase (CRL). Comparison of these results with those of crude CRL reveal significant differences. As was seen in resolution through hydrolysis, 1 a marked improvement in enantioselectivity is realized with the CLEC. Additionally, the stability afforded the enzyme in CLEC form leads to a higher activity in organic solvent.

Cross‐Linked Crystals of Subtilisin Versatile Catalysts for Organic Synthesis

Cross-linked enzyme crystals (CLECs) of subtilisin exhibit excellent activity in aqueous and various organic solvents. This catalyst is more stable than the native enzyme in both aqueous and mixed aqueous/organic solutions. Subtilisin-CLEC was shown to be a versatile catalyst. It was used for the syntheses of peptides and peptidomimetics, mild hydrolysis of amino acid and peptide amides, enantio- and regioselective reactions, and transesterifications.