Dissolution and Absorption of Inhaled Drug Particles in the Lungs.

Dry powder inhalation therapy has been effective in treating localized lung diseases such asthma, chronic obstructive pulmonary diseases (COPD), cystic fibrosis and lung infections. In vitro characterization of dry powder formulations includes the determination of physicochemical nature and aerosol performance of powder particles. The relationship between particle properties (size, shape, surface morphology, porosity, solid state nature, and surface hydrophobicity) and aerosol performance of an inhalable dry powder formulation has been well established. However, unlike oral formulations, there is no standard dissolution method for evaluating the dissolution behavior of the inhalable dry powder particles in the lungs. This review focuses on various dissolution systems and absorption models, which have been developed to evaluate dry powder formulations. It covers a summary of airway epithelium, hurdles to developing an in vitro dissolution method for the inhaled dry powder particles, fine particle dose collection methods, various in vitro dissolution testing methods developed for dry powder particles, and models commonly used to study absorption of inhaled drug.

Simulation of respiratory tract lining fluid for in vitro dissolution study.

Introduction: Drug particles inhaled via the respiratory system must first dissolve in the respiratory tract lining fluid (RTLF) that lies on the surfaces of airways and alveoli, so that they are absorbed and have therapeutic action. Artificial simulated RTLFs are often used for in vitro dissolution studies to determine the solubility and dissolution of inhaled drug particles. Such studies can be used to predict bioavailability minimizing the requirement for in vivo studies. Numerous studies have been conducted to develop bio-relevant simulated RTLFs; however, to date, there is no singular simulated RTLF that closely resembles human RTLF.Areas covered: This review focuses on the composition of natural and simulated RTLFs and their use in in vitro dissolution studies.Expert opinion: There is variation in the composition and thickness of RTLF along the respiratory tract. Identification of the actual concentration of components of endogenous RTLF present in different areas of the respiratory tract helps in the development of region-specific simulated RTLFs. It is recommended that region-specific simulated RTLFs can be prepared by varying concentration of major RTLF components like mucus/gel simulants, lipids/surfactants, peptides/proteins, and inorganic/organic salts.

Preparation of Squalene Oil-Based Emulsion Adjuvants Employing a Self-Emulsifying Drug Delivery System and Assessment of Mycoplasma hyopneumoniae-Specific Antibody Titers in BALB/c Mice.

In this study, a self-emulsifying drug delivery system (SEDDS) was employed to prepare novel squalene oil-based emulsion adjuvants. Deionized water, 0.01% and 0.02% (w/v) carbomer solutions of C-971P NF and C-940 grades were used to prepare emulsions containing 3%, 5% and 10% of squalene oil. Altogether 15 candidate emulsions were prepared and used as adjuvants for the delivery of a combination vaccine containing a porcine circovirus type 2 (PCV2) antigen and inactivated Mycoplasma hyopneumoniae (J101 strain) antigen. Most of the emulsions showed droplet sizes in the submicron range and maintained zeta potential values between -40 mV to 0 mV for six months, indicating good physical stability as a vaccine adjuvant. Emulsion-based candidate adjuvants prepared with SEDDS technology stimulated IgG, IgG1 and IgG2a like a currently commercially available adjuvant, Montanide ISATM 201, and they were safe and their Mycoplasma hyopneumoniae-specific antibody titers were considered as comparable with that of Montanide ISATM 201.

Determination of Mycoplasma hyopneumoniae-Specific IgG, IgG1, and IgG2a Titers in BALB/c Mice Induced by Mineral Oil-Based Oil-in-Water Emulsion Adjuvants Prepared Using a Self-Emulsifying Drug Delivery System.

We prepared mineral oil-based emulsion adjuvants by employing simple self-emulsifying drug delivery system (SEDDS). Mineral oil emulsions (3%, 5%, and 7%) were prepared using deionized water and C-971P NF and C-940 grade carbomer solutions with concentrations 0.01% (w/v) and 0.02% (w/v). In total, 15 emulsions were prepared and mixed with a solution containing inactivated Mycoplasma hyopneumoniae (J101 strain) antigen and porcine circovirus type 2 antigen to prepare vaccines. Droplet sizes in the submicron range and zeta potential values between - 40 and 0 mV were maintained by most emulsion adjuvants for a period of 6 months. Emulsion adjuvants were regarded safe, and their M. hyopneumoniae-specific IgG, IgG1, and IgG2a titers were either better or comparable to those of aluminum gel.

Complex formulations, simple techniques: Can 3D printing technology be the Midas touch in pharmaceutical industry?

3D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3D printing was developed in the 1980s and the technology has found widespread industrial applications for production from automotive parts to machine tools, its application in pharmaceutical area is still limited. However, the potential of 3D printing in the pharmaceutical industry is now being recognized. The ability of 3D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes, sizes and textures that are difficult to produce using traditional techniques. However, there are various challenges associated with the proper application of 3D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review, an overview is provided on the various 3D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.

Vaccine adjuvants: smart components to boost the immune system.

Vaccination is an effective approach to prevent the consequences of infectious diseases. Vaccines strengthen immunity and make individuals resistant to infections with pathogens. Although conventional vaccines are highly immunogenic, they are associated with some safety issues. Subunit vaccines are safe, but they require adjuvants to stimulate the immune system because of their weaker immunogenicity. Adjuvants are entities incorporated into vaccines to increase the immunogenic responses of antigens. They play a crucial role in increasing the potency and efficacy of vaccines. Different adjuvants have different modes of action; therefore, a better understanding of their immunology could provide guidance for the development of novel adjuvants. Numerous studies have been conducted using different types of adjuvants to characterize their potency and safety; however, in practice, only few are used in human or animal vaccines. This review aims to introduce the different modes of action of adjuvants and give insight into the types of adjuvants that possess the greatest potential for adjuvanticity.