Application of Combinatorial Methods for the Identifi cation of Synthetic Hair-Conditioning Polymers.

Cationic conditioning polymers have a role as deposition aids for depositing benefit agents such as silicone polymers and are used in shampoo formulations to provide improved combing properties, feel, and look. The objective of this work was to develop synthetic high-performance polymeric conditioning agents that exhibit conditioning performance as good as, or better than, the current commercially available polymers. We describe the application of high throughput methods to identify high-performance synthetic hair-conditioning polymers through using high throughput combinatorial methods for polymer synthesis and screening to prepare several hundred cationic polymer candidates. Shampoo formulations were then formulated with these polymers; hair tresses were treated with these formulations and tested via a parallel automated wet combing method. Three high-performing polymer candidates were selected for further evaluation, prepared on a larger scale and evaluated via a panel study. A (3-acrylamidopropyl)trimethylammonium chloride-vinyl monomer-based cationic copolymer is shown to exhibit hair conditioning efficiency equal to or greater than that of a high-performance cellulose ether-based polymer, SOFTCAT™ SL-5 (Polyquaternium-67) in a shampoo formulation.

High-Throughput Raman Spectroscopy Screening of Excipients for the Stabilization of Amorphous Drugs.

Low aqueous solubility of active pharmaceutical ingredients (APIs) is an enduring problem in pharmaceutical development, and it is becoming increasingly prevalent among new drug candidates. It is estimated that about 40% of drugs in the development pipeline and approximately 60% of the drugs coming directly from discovery suffer from poor aqueous solubility and slow dissolution, thereby reducing their bioavailability and efficacy and thus preventing their commercialization. It is well known that utilizing the amorphous form of a drug can be a useful approach to improve the dissolution rate and solubility of poorly water-soluble APIs. Amorphous compounds are thermodynamically unstable, but they can be stabilized by combining them with a carrier polymer (excipient) to form a solid dispersion. High-throughput Raman spectroscopy was used in this study to identify excipients that promote formation and stabilization of the amorphous drug form in solid dispersions. Four model APIs were used as poorly soluble drug candidates: ketoprofen, danazol, griseofulvin, and probucol. The Raman signals of excipients were generally negligible, and therefore Raman bands from the drugs were used with minimal spectral pre-processing. By comparing Raman spectra collected from the APIs in the crystalline and molten state, appropriate spectral features and regions were identified for the development of semi-quantitative methods to determine the amorphous content for each API. It is demonstrated that methods based on peak intensity ratio, peak width, peak distance, and classical least squares can all be effective methods for the screening of excipients. Interesting excipient-dependent phase transformation behavior was also observed for probucol.