Enhancing topical delivery of ISRIB: Optimizing cream formulations with chemical enhancers and pH adjustment

Int J Pharm. 2024 Nov 15:665:124661. doi: 10.1016/j.ijpharm.2024.124661. Epub 2024 Sep 6.

Abstract

Chemical warfare agents, particularly vesicants like lewisite, pose a threat due to their ability to cause skin damage through accidental exposure or deliberate attacks. Lewisite rapidly penetrates the skin, causing inflammation and blistering. This study focuses on developing a cream formulation of a therapeutic agent, called integrated stress response inhibitor (ISRIB), to treat lewisite-induced injuries. Moreover, animal studies demonstrate a molecular target engagement (ISR) and significant efficacy of ISRIB against lewisite-induced cutaneous injury. The goal of this formulation is to enhance the delivery of ISRIB directly to affected skin areas using an oil-in-water cream emulsion system. We investigated various excipients, including oils, surfactants, emollients, and permeation enhancers, to optimize ISRIB's solubility and penetration through the skin. The result of this study indicated that the optimal formulation includes 30 % w/w of N-Methyl-2-pyrrolidone, dimethyl sulfoxide and Azone® at a pH of 5. 5. It delivered the highest amount of ISRIB into the skin, demonstrating highest skin absorption with no detectable systemic exposure. Additionally, characterization of the cream, including texture analysis, emulsion type, and content uniformity, confirmed its' suitability for topical application. These findings suggest that ISRIB cream formulation is a promising approach for the localized treatment of skin injuries caused by lewisite.

Keywords: Chemical enhancers; Cream formulation; ISRIB; Lewisite; Pharmaceutical formulation; Topical drug delivery; pH optimization.

MeSH terms

  • Administration, Cutaneous*
  • Animals
  • Chemical Warfare Agents / toxicity
  • Chemistry, Pharmaceutical / methods
  • Dimethyl Sulfoxide / administration & dosage
  • Dimethyl Sulfoxide / chemistry
  • Drug Compounding
  • Emollients / administration & dosage
  • Emollients / chemistry
  • Emulsions*
  • Excipients* / chemistry
  • Hydrogen-Ion Concentration
  • Pyrrolidinones
  • Skin Absorption* / drug effects
  • Skin Cream / administration & dosage
  • Skin* / drug effects
  • Skin* / metabolism
  • Solubility
  • Surface-Active Agents / chemistry
  • Swine

Substances

  • Excipients
  • Emulsions
  • Dimethyl Sulfoxide
  • N-methylpyrrolidone
  • Emollients
  • Surface-Active Agents
  • Chemical Warfare Agents
  • Pyrrolidinones