Current Pharmaceutical Biotechnology - Volume 16, Issue 11, 2015

Pharmaceutical biotechnology has been showing therapeutic success never achieved with conventional drug molecules. Therefore, biopharmaceutical products are currently well-established in clinic and the development of new ones is expected. These products comprise mainly therapeutic proteins, although nucleic acids and cells are also included. However, according to their sensitive molecular structures, the efficient delivery of biopharmaceuticals is challenging. Several delivery systems (e.g. microparticles and nanoparticles) composed of different materials (e.g. polymers and lipids) have been explored and demonstrated excellent outcomes, such as: high cellular transfection efficiency for nucleic acids, cell targeting, increased proteins and peptides bioavailability, improved immune response in vaccination, and viability maintenance of microencapsulated cells. Nonetheless, important issues need to be addressed before they reach clinics. For example, more in vivo studies in animals, accessing the toxicity potential and predicting in vivo failure of these delivery systems are required. This is the Part I of two review articles, which presents the state of the art of delivery systems for biopharmaceuticals. Part I deals with microparticles and polymeric and lipid nanoparticles.

Biopharmaceuticals are a generation of drugs that include peptides, proteins, nucleic acids and cell products. According to their particular molecular characteristics (e.g. high molecular size, susceptibility to enzymatic activity), these products present some limitations for administration and usually parenteral routes are the only option. To avoid these limitations, different colloidal carriers (e.g. liposomes, micelles, microemulsions and dendrimers) have been proposed to improve biopharmaceuticals delivery. Liposomes are promising drug delivery systems, despite some limitations have been reported (e.g. in vivo failure, poor long-term stability and low transfection efficiency), and only a limited number of formulations have reached the market. Micelles and microemulsions require more studies to exclude some of the observed drawbacks and guarantee their potential for use in clinic. According to their peculiar structures, dendrimers have been showing good results for nucleic acids delivery and a great development of these systems during next years is expected. This is the Part II of two review articles, which provides the state of the art of biopharmaceuticals delivery systems. Part II deals with liposomes, micelles, microemulsions and dendrimers.

Protein-based biopharmaceuticals are often produced in mammalian cell cultures, which are more expensive than microbial systems but capable of authentic post-translational modifications. The costs are lower if plants are used as an alternative platform to produce complex proteins such as monoclonal antibodies, vaccines and enzymes. This review highlights recent advances that have been achieved in plant-based biopharmaceutical production platforms in terms of expression strategies, product yields and process development. The first generation of plant-derived pharmaceuticals now entering the market is also discussed. Finally, the review considers the downstream processing of plant-derived pharmaceuticals which can account for up to 80% of the production costs. In this context, recent improvements in clarification and integrated process methods will have a strong impact on the economic feasibility of production, especially if supported by and combined with process analytical technology as part of the quality-by-design initiative.

The shift from empirical to science-based process development is considered to be a key factor to increase bioprocess performance and to reduce time to market for biopharmaceutical products in the near future. In the last decade, expanding knowledge in systems biology and bioprocess technology has delivered the foundation of the scientific understanding of relationships between process input parameters and process output features. Based on this knowledge, advanced process development approaches can be applied to maximize process performance and to generate process understanding. This review focuses on tools which enable the integration of physiological knowledge into cell culture process development. As a structured approach, the availability and the proposed benefit of the application of these tools are discussed for the subsequent stages of process development. The ultimate aim is to deliver a comprehensive overview of the current role of physiological understanding during cell culture process development from clone selection to the scale-up of advanced control strategies for ensuring process robustness.

The prevalence and incidence of autoimmune and allergic diseases have increased dramatically over the last several decades, especially in the developed world. The treatment of autoimmune and allergic diseases is typically with the use of non-specific immunosuppressive agents that compromise the integrity of the host immune system and therefore, increase the risk of infections. Antigenspecific immunotherapy by reinstating immunological tolerance towards self antigens without compromising immune functions is a much desired goal for the treatment of autoimmune and allergic diseases. Mucosal administration of antigen is a long-recognized method of inducing antigen-specific immune tolerance known as oral tolerance, which is viewed as having promising potential in the treatment of autoimmune and allergic diseases. Plant-based expression and delivery of recombinant antigens provide a promising new platform to induce oral tolerance, having considerable advantages including reduced cost and increased safety. Indeed, in recent years the use of tolerogenic plants for oral tolerance induction has attracted increasing attention, and considerable progress has been made. This review summarizes recent advances in using plants to deliver tolerogens for induction of oral tolerance in the treatment of autoimmune, allergic and inflammatory diseases.

Tissue-engineered constructs made of biotechnology-derived materials have been preferred due to their chemical and physical composition, which offers both high versatility and a support to enclose/ incorporate relevant signaling molecules and/or genes known to therapeutically induce tissue repair. Herein, a critical overview of the impact of different biotechnology-derived materials, scaffolds, and recombinant signaling molecules over the behavior of cells, another element of tissue engineered constructs, as well its regulatory role in tissue regeneration and disease progression is given. Additionally, these tissue-engineered constructs evolved to three-dimensional (3D) tissue-like models that, as an advancement of two-dimensional standard culture methods, are expected to be a valuable tool in the field of drug discovery and pharmaceutical research. Despite the improved design and conception of current proposed 3D tissue-like models, advanced control systems to enable and accelerate streamlining and automation of the numerous labor-intensive steps intrinsic to the development of tissue-engineered constructs are still to be achieved. In this sense, this review intends to present the biotechnology- derived materials that are being explored in the field of tissue engineering to generate 3D tissue-analogues and briefly highlight their foremost breakthroughs in tissue regeneration and drug discovery. It also aims to reinforce that the crosstalk between tissue engineering and pharmaceutical biotechnology has been fostering the outcomes of tissue engineering approaches through the use of biotechnology-derived signaling molecules. Gene delivery/therapy is also discussed as a forefront area that represents another cross point between tissue engineering and pharmaceutical biotechnology, in which nucleic acids can be considered a “super pharmaceutical” to drive biological responses, including tissue regeneration.

The herpes simplex virus (HSV) is a widespread human pathogen and for many reasons the development of anti-herpetic drugs from natural products has been encouraged. Adenanthera pavonina (Ap) is a medicinal plant widely used in Brazil, among other uses. Herein, a native Ap seed polysaccharide (PLSAp) and its chemically sulfated derivate (SPLSAp) were studied by Fourier transform IR spectra (FT-IR), gel permeation chromatography (GPC) for molar mass determination and their intrinsic viscosity [η]. Biologically, the compounds were evaluated for anti-HSV activity, in HEp2 cell cultures. The cytotoxic concentrations (CC50) and the inhibitory concentrations (IC50) of the polysaccharides were determined by the colorimetric assay (dimethyl-thiazolyl-diphenyltetrazolium bromide) and plaque reduction assay (PRA), respectively. The SPLSAp showed a better antiviral activity when compared to the PLSAp with a CC50 of 500 μg/ml, the IC50 equal to 15μg/ml and the selectivity index (SI) of 33.3. The time-of-addition and the time-of-removal assays demonstrated the highest inhibitory activity between 8-16h after the infection. The inhibition of viral DNA and protein syntheses by SPLSAp monitored by PCR and immunofluorescence assay (IFA), respectively, has also demonstrated. These findings demonstrated that the SPLSAp inhibited HSV-1 infection in different steps of the replication and, therefore, represents a valuable compound for preclinical studies in anti-herpetic therapy.