Pharmacokinetic and screening studies of the interaction between mononuclear phagocyte system and nanoparticle formulations and colloid forming drugs.

Studies have shown that nanoparticles (NPs) are cleared through the mononuclear phagocyte system (MPS). Pharmacokinetic studies of Doxil, DaunoXome, micellar doxorubicin (SP1049C) and small molecule (SM) doxorubicin were performed in SCID mice, Sprague-Dawley rats, and beagle dogs. An ex vivo MPS profiling platform was used to evaluate the interaction between the same agents, as well as colloid-forming and non-colloid forming SM drugs.

Where Are the Nanodrugs? An Industry Perspective on Development of Drug Products Containing Nanomaterials.

While nanotechnology advancements have been applied to pharmaceutical products, the number of approved nanodrugs by global health authorities has not kept pace with research and development investments in the field. This article reviews the history of nanodrug development and provides an industrial context for realistic expectations in the future.

Nanomedicines: From Bench to Bedside and Beyond.

Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration.

Preference for pharmaceutical formulation and treatment process attributes.

Purpose: Pharmaceutical formulation and treatment process attributes, such as dose frequency and route of administration, can have an impact on quality of life, treatment adherence, and disease outcomes. The aim of this literature review was to examine studies on preferences for pharmaceutical treatment process attributes, focusing on research in diabetes, oncology, osteoporosis, and autoimmune disorders.

Methods: The literature search focused on identifying studies reporting preferences for attributes of the pharmaceutical treatment process.

Nanomedicine drug development: a scientific symposium entitled "Charting a roadmap to commercialization".

The use of nanotechnology in medicine holds great promise for revolutionizing a variety of therapies. The past decade witnessed dramatic advancements in scientific research in nanomedicines, although significant challenges still exist in nanomedicine design, characterization, development, and manufacturing. In March 2013, a two-day symposium "Nanomedicines: Charting a Roadmap to Commercialization," sponsored and organized by the Nanomedicines Alliance, was held to facilitate better understanding of the current science and investigative approaches and to identify and discuss challenges and knowledge gaps in nanomedicine development programs.

Biological characterization of a heterodimer-selective retinoid X receptor modulator: potential benefits for the treatment of type 2 diabetes.

Specific retinoid X receptor (RXR) agonists, such as LG100268 (LG268), and the thiazolidinedione (TZD) PPARgamma agonists, such as rosiglitazone, produce insulin sensitization in rodent models of insulin resistance and type 2 diabetes. In sharp contrast to the TZDs that produce significant increases in body weight gain, RXR agonists reduce body weight gain and food consumption. Unfortunately, RXR agonists also suppress the thyroid hormone axis and generally produce hypertriglyceridemia.

Light scattering, CD, and ligand binding studies of ferrihemoglobin-polyelectrolyte complexes.

Quasi-elastic light scattering (QELS), electrophoretic light scattering (ELS), CD spectroscopy, and azide binding titrations were used to study the complexation at pH 6.8 between ferrihemoglobin and three polyelectrolytes that varied in charge density and sign. Both QELS and ELS show that the structure of the soluble complex formed between ferrihemoglobin and poly(diallyldimethylammonium chloride) [PDADMAC] varies with protein concentration.

Effects of non-covalent self-association on the subcutaneous absorption of a therapeutic peptide.

Purpose: To utilize an acylated peptide as a model system to investigate the relationships among solution peptide conformation, non-covalent self-association, subcutaneous absorption and bioavailability under pharmaceutically relevant solution formulation conditions.

Methods: CD spectroscopy, FTIR spectroscopy, equilibrium sedimentation, dynamic light scattering, and size exclusion chromatography were employed to characterize the effects of octanoylation on conformation and self-association of the 31 amino acid peptide derivative des-amino-histidine(7) arginine(26) human glucagon-like peptide (7-37)-OH (IP(7)R(26)GLP-1). Hyperglycemic clamp studies were performed to compare the bioavailability, pharmacokinetics, and pharmacodynamics of solution formulations of oct-IP(7)R(26)GLP-1 administered subcutaneously to normal dogs.

Physicochemical basis for the rapid time-action of LysB28ProB29-insulin: dissociation of a protein-ligand complex.

The rate-limiting step for the absorption of insulin solutions after subcutaneous injection is considered to be the dissociation of self-associated hexamers to monomers. To accelerate this absorption process, insulin analogues have been designed that possess full biological activity and yet have greatly diminished tendencies to self-associate. Sedimentation velocity and static light scattering results show that the presence of zinc and phenolic ligands (m-cresol and/or phenol) cause one such insulin analogue, LysB28ProB29-human insulin (LysPro), to associate into a hexameric complex.

Effect of salts on the structure of a potent analog of growth hormone releasing hormone as determined by optical spectroscopy.

Optical spectroscopic methods (circular dichroism, analytical ultracentrifugation, and static light scattering) were employed to study the solution behavior of an N-terminal-acylated 76-residue analog of growth hormone releasing hormone (GHRH). The GHRH analog had a 30% helical configuration in aqueous acidic solution, unlike other GHRH analogs that had a random coil configuration in aqueous solutions, and self-associated. High concentrations (7 M) of urea were required to obtain monomeric peptide, but such urea concentrations unfolded the peptide.

Acid stabilization of human growth hormone equilibrium folding intermediates.

Equilibrium denaturation experiments were performed on human growth hormone (hGH) under acidic conditions (pH 1.5-3.0) and different protein concentrations.

Reversible adsorption of soluble hexameric insulin onto the surface of insulin crystals cocrystallized with protamine: an electrostatic interaction.

Mixing pharmaceutical preparations of soluble neutral regular insulin solution (NRI) and neutral protamine Hagedorn (NPH) crystalline insulin suspension leads to a reduction in the measurable amount of soluble insulin in the formulation supernatant. However in spite of the loss in soluble insulin, the time-actions of these components have been shown, in clinical trials, to be unaffected. The interaction between these different physical forms of insulin has been studied using reversed-phase HPLC, isothermal titrating calorimetry, and Doppler electrophoretic light scattering analysis.

Evidence for a self-associating equilibrium intermediate during folding of human growth hormone.

It has been previously shown, by equilibrium denaturation, that human growth hormone (hGH) folds by a cooperative two-state process. This is in contrast to the folding pathways of other nonhuman growth hormones that contain stable monomeric and multimeric equilibrium intermediates. We have reinvestigated the equilibrium denaturation of hGH at higher protein concentrations and found smooth transitions from the native to denatured state, but the calculated free energy for unfolding, delta G, decreases with increasing protein concentration.

Site-directed mutagenesis to probe protein folding: evidence that the formation and aggregation of a bovine growth hormone folding intermediate are dissociable processes.

Bovine growth hormone (bGH) forms a stable folding intermediate that aggregates at elevated concentrations (greater than 10 microM). Thermodynamic and kinetic studies have shown that the formation of this bGH folding intermediate and its aggregation are separate processes, implying that selective modifications of bGH can lead to their independent modulation. In addition, a bGH region that includes amino acid residues 109-133 appears to be directly involved in this aggregation process.

Spectroscopic analysis of [Trp3]-beta-casomorphin analogs. Comparative structure conformation-activity studies.

A series of [3-tryptophan]-beta-casomorphin-5([Trp3]-beta-CM-5) analogs were investigated by circular dichroism (CD) and fluorescence spectroscopy to explore their structure-conformation properties in solution. In addition, the comparative opioid activities of these compounds were evaluated using the in vitro guinea pig ileum (GPI) and mouse vas deferens (MVD) assays. Specifically, the pentapeptide sequence of [Trp3]-beta-CM-5, H-Tyr-Pro-Trp-Pro-Gly-OH (I) was modified at Pro-2 and Pro-4 by D-Pro substitutions to provide two diastereometric analogs, [Trp3-D-Pro-4]-beta-CM-5 (II) and [D-Pro2,4,Trp3]-beta-CM-5 (III).

Investigations of protein structure with optical spectroscopy: bovine growth hormone.

Optical spectroscopy provides a wealth of information about protein structure that is difficult to obtain from other methods. Investigations of changes in primary, secondary, tertiary, and quaternary structure are particularly well-suited for optical techniques such as UV absorption, circular dichroism, fluorescence, Raman and infrared spectroscopy, as well as light scattering methods. Each method has unique areas of applicability and contributes to structure determination in a different manner.

Folding of bovine growth hormone is consistent with the molten globule hypothesis.

Previous results from equilibrium and kinetic studies of the folding of bovine growth hormone (bGH) have demonstrated that bGH does not follow a simple two-step folding mechanism. These results are summarized and interpreted according to the "molten globule" model. The molten globule state of bGH is characterized as a folding intermediate which is largely alpha-helical, retains a compact hydrodynamic radius, has packing of the aromatic side chains that is similar to the unfolded state, and possesses a solvent-exposed hydrophobic surface along helix 106-127 that readily leads to association.

Fluorescence quenching studies of bovine growth hormone in several conformational states.

The use of steady-state fluorescence quenching methods is reported as a probe of the accessibility of the single fluorescent tryptophan residue of bovine growth hormone (bGH, bovine somatotropin, bSt) in four solution-state conformations. Different bGH conformations were prepared by using previous knowledge of the multi-state nature of the equilibrium unfolding pathway for bGH: alterations in denaturant and protein concentration yielded different bGH conformations (native, monomeric intermediate, associated intermediate and unfolded). Because the intramolecular fluorescence quenching which occurs in the native state is reduced when the protein unfolds to any of the other conformations, steady-state fluorescence intensity measurements can be used to monitor bGH unfolding as well as the formation of the associated intermediate.

Stabilization of an associated folding intermediate of bovine growth hormone by site-directed mutagenesis.

By using oligonucleotide-directed mutagenesis, Lys-112 of bovine growth hormone (bGH) was changed to leucine, and its resulting effect on folding was studied. Equilibrium denaturation curves for the mutant protein exhibit biphasic or nonsymmetrical transitions by a variety of spectroscopic and hydrodynamic techniques, whereas the wild-type protein at the same concentration exhibits symmetrical transitions. The mutant protein refolds slower (by a factor of 30) and more readily precipitates upon refolding than the wild-type protein.

Characterization of an associated equilibrium folding intermediate of bovine growth hormone.

In the preceding paper [Havel, H. A., Kauffman, E.

Reversible self-association of bovine growth hormone during equilibrium unfolding.

Previous investigations have shown that bovine growth hormone (bGH, somatotropin) unfolds through a reversible multistate process with at least one stable equilibrium intermediate. In extending our knowledge of the folding process for bGH, we demonstrate that a self-associated form of partially denatured bGH is formed during equilibrium unfolding experiments. The self-associated species has been identified by hydrodynamic measurements (size exclusion high-performance liquid chromatography and static and dynamic light scattering) and by measurements of the bGH concentration dependence of aromatic amino acid spectral properties (fluorescence, second-derivative absorption, and circular dichroism).

Equilibrium denaturation of pituitary- and recombinant-derived bovine growth hormone.

Holladay and co-workers [Holladay, L. A., Hammonds, R.

Analysis of the variance components in a pharmaceutical aerosol product: lodoxamide tromethamine.

The contributions of several components to the variance in lodoxamide delivery from lodoxamide tromethamine metered-dose aerosol containers have been estimated. Two aerosol lots, manufactured with mean diameters of 2.3 and 7.

Determination of minoxidil in bulk drug and pharmaceutical formulations by ion-pairing high-performance liquid chromatography.

An ion-pairing liquid chromatographic method with UV detection is described for the determination of minoxidil in bulk drug, compressed tablet, and topical solution formulations. The chromatographic system consists of a microparticulate octadecylsilica column and a mobile phase composed of sodium dioctylsulfosuccinate in aqueous methanol (pH 3). The bulk drug and the topical solution samples are prepared by the dissolution of the drug in internal standard solution.