Polyisobutene 1200

Phaechamud, Thawatchai, et al. Silkaporn University Science & Technology Journal, 2012, 6(2), 9-19.

It can be made without heating the emulsion which is the perfect production process for heat sensitive raw materials and energy efficient. This was a research study assessing whether it would be possible to prepare clotrimazole (ctz) cream base using emulsifying polymers without heating.
Optimized formulation of ctz cream
A stable and acceptable cream base that is easily mixed with clotrimazole was prepared at room temperature using isopropyl isostearate as the oil phase, emulsifying polymers as emulsifiers, concentrated parabens as preservatives, polyethylene glycol 400 as a solubilizer, and distilled water as the aqueous phase. The ratios were 15:3:1:5:75, respectively. The type of emulsifying polymer affected drug release but not antifungal activity. Among them, emulsifying polymer Se 265, which is composed of ammonium acrylate/acrylamide copolymer and polyisobutylene and polysorbate 20, performed best.
Performance of ctz cream
The drug release and antifungal activity of the optimized clotrimazole cream formulation were not significantly different from those of the commercial formulation product. It was shown that clotrimazole cream can be prepared without heating using emulsifying polymers.

Schulz, Martin, et al. European journal of pharmaceutical sciences, 2010, 41(5), 675-684.

This work compares the performance of crospovidone(CPVP)-based patches containing pure drug or adsorbate with different adhesives (such as polyisobutylene PIB and acrylic adhesives) in terms of drug physical state and drug release.
Patch performance based on polyisobutylene adhesives
· Integrating drug adsorbates onto crospovidone within polyisobutene blends resulted in patches free from crystals. The release of the drug from these patches was unaffected by the molecular weight distribution of polyisobutene, likely because the release primarily occurred through fluid-filled channels.
· Increased saturation (or supersaturation) in these systems led to higher thermodynamic activity of the drugs, resulting in enhanced drug release. The crystal-free polyisobutene patch did not exhibit drug recrystallization after three months at 25 °C/60% RH and 40 °C/75% RH.
· Additionally, incorporating 10-30% CPVP into PIB matrices enhanced their adhesive properties both in vitro and in vivo. To optimize skin adhesion, the PIB's molecular weight composition should be aligned with the CPVP content. As the PIB molecular weight does not affect drug release from patches containing adsorbates, it can be adjusted to achieve the desired adhesive characteristics.