Development of nano alpha-ketoglutarate nebulization formulation and its pharmacokinetic and safety evaluation in healthy human volunteers for cyanide poisoning

Development and clinical study of submicronic-atropine sulphate respiratory fluid as a novel organophosphorous poisoning antidote

CONTEXT

Increased use of organophosphate insecticides (OPI) and possibility of terror groups using stocks of nerve agents underscore the need to develop effective and safe antidotes. While intramuscular administration of antidotes like atropine sulphate (AS) has certain lacunae, intravenous route may not be always feasible in emergency field conditions.

OBJECTIVE

Objective was (a) to develop a novel inhalable submicronic-AS respiratory fluid as potential antidote for OPI poisoning, (b) in-vitro and in-vivo evaluation in terms of respiratory fraction, and (c) clinical study to assess drug bioavailability in blood and atropinization pattern post-inhalation.

METHODS

Formulation was optimized on the basis of particle size of aerosolized droplets and in-vitro nebulization rate. Anderson cascade impaction (ACI) studies were carried out to validate the advantage of test formulation in terms of respirable fraction. Six healthy volunteers were inhaled the test formulation and blood bioavailability and atropinization were noted serially. Gamma scintigraphy was used to quantify total and regional lung deposition of nebulized AS in-vivo.

RESULTS

The formulation was optimized using 30% ethanol-saline with particle size in the range of 350-500 nm. In-vitro ACI data showed high respirable fraction (82.6 ± 3.1%) for the test formulation. In-vivo scintigraphy suggested whole lung deposition of 80.2 ± 6.8% of the total inhaled dose. Early blood bioavailability and atropinization pattern confirmed that therapeutic concentration of the drug in blood was reached within 5 min.

CONCLUSIONS

3% submicronic-AS respiratory fluid might be used as potential prophylactic/therapeutic option against OPI poisoning with several advantages over intramuscular injection, including early blood bioavailability and atropinization.

Safety of nanosuspensions in drug delivery

Nanosuspension technology is currently undergoing dramatic expansion in pharmaceutical science research and development. However, most of the research efforts generally focus on formulation and potential beneficial description, while the research into potential toxicological effects and implications (i.e., in vivo safety and health effects) is lacking. This review identifies some of the key factors for studying nanosuspension safety and the potential undesired effects related to nanosuspension exposure. The key factors for discussion herein include particle characterization, preparation approach, composition, and excipients of the formulation and sterilization methods. A few comments on the primary and required safety aspects of each administration route are also reviewed.

Formulation, preclinical and clinical evaluation of a new submicronic arginine respiratory fluid for treatment of chronic obstructive pulmonary disorder

Inhalational drugs often suffer from low pulmonary deposition due to their micronized size. Aim of present study was development and evaluation of a novel submicronic L-arginine respiratory fluid formulation for treatment of cardiopulmonary complications associated with chronic obstructive pulmonary disorder (COPD). Objectives were (a) to develop and characterize submicronic L-arginine respiratory fluid formulation, (b) pre-clinical safety/toxicity study in 2-animal species, (c) in vitro and in vivo evaluation in terms of respiratory fraction, and (d) clinical study to assess safety/efficacy in healthy volunteers/COPD patients. Formulation was optimized on the basis of particle size of aerosolized medication with particle size in the range of 400–500 nm. Anderson cascade impaction (ACI) studies were performed to validate the advantage in terms of respirable fraction, which indicated a high respirable fraction (51.61 ± 3.28) for the developed formulation. In vivo pulmonary deposition pattern of optimized formulation was studied using gamma scintigraphy in human volunteers using ^99mTc-arginine as radiotracer. It clearly demonstrated a significant pulmonary deposition of the submicronic formulation in various lung compartments. Efficacy of the developed formulation was further assessed in COPD patients (n = 15) by evaluating its effect on various cardiopulmonary parameters (spirometry, pulse-oxymetry, echocardiography and 6-min walk test). A marked improvement was seen in patients after inhalation of submicronic arginine in terms of their cardiopulmonary status. Results suggest that submicronic arginine respiratory fluid has the potential to be developed into an attractive therapeutic option for treating COPD associated cardiopulmonary complications.

Ameliorative potential of alpha-ketoglutaric acid (AKG) on acute lung injuries induced by ammonia inhalation in rats

INTRODUCTION

Toxicants such as ammonia, if inhaled, can damage respiratory tract leading to acute lung injury and pulmonary edema. Besides being a possible threat for the workers in chemical industry, easy availability and the toxic nature of ammonia may be used by terror groups for inflicting mass casualty among vulnerable population. In the present study, we have evaluated the therapeutic efficacy of alpha-ketoglutarate (AKG) to mitigate acute effects of ammonia on lung structure and antioxidant status in experimental animals.

METHODS

Acute lung injury (ALI) models were developed by inhalation of aerosols of liquid ammonia in male Sprague Dawley rats. AKG (5%) respiratory fluid was inhaled by nebulization once daily for 5 days. Animals were euthanized and their blood samples were collected for hematology and serum biochemistry analysis. Total cell count, total protein (TP), lactate dehydrogenase (LDH), antioxidant enzyme activity (CAT, SOD, GSH), and malonaldialdehyde (MDA) formation were measured in bronchoalveolar lavage (BAL) fluid.

RESULTS

Treatment with AKG showed significant lung protection by lowering the levels of total cell count, TP, LDH, superoxide dismutase (SOD), and MDA in BAL fluid. There was a marked increase in catalase (CAT) and glutathione (GSH) content of BAL fluid post-AKG inhalation. Histopathology of lung tissue correlated with cellular and biochemical findings indicate therapeutic efficacy of AKG against ammonia-induced lung injuries.

CONCLUSIONS

The data suggest a possible therapeutic role of AKG inhalation against ammonia-induced structural and inflammatory changes in the lung.