Formulation Development of Rotigotine Transdermal System Using Dot-Matrix Technology

The purpose of this research was to prepare and evaluate drug-in-adhesive type patches of rotigotine using dot-matrix technology, which is the new generation of drug-in-adhesive transdermal delivery system (TDS) that deliver drug therapy through less patch surface area and without compromising adhesion. Preformulation studies, like solubility in permeation enhancers, compatibility study, transmission study, uptake study, and crystallization study of rotigotine in various pressure-sensitive adhesive (PSA) polymers were performed. Transdermal system was prepared by solvent casting method. Central composite design (CCD) was chosen for optimization of the formulation. Design of experiment (DoE) was used to study the impact of critical formulation parameters, like silicone adhesive concentration, povidone K29/32 concentration, and propylene glycol concentration. Crystallization study of rotigotine in different PSAs suggested that crystal inhibitor is required to load drugs above 5%. Selection of optimum batch was made using a constraint-based graphical optimization technique. The optimum batch exhibited desired in vitro adhesion parameters, like peel, tack, shear, and permeation rate, which is suitable for 3 days’ wear properties and desired permeation rate. The optimum batch was evaluated for appearance, weight of matrix, thickness, % assay of drug content, in vitro adhesion testing, cold flow study, and ex vivo skin permeation studies. Backing film Scotchpak 9730 and release liner Scotchpak-1022 was selected based on transmission and uptake study of rotigotine. Stability study indicates that developed formulation remains stable. The present research confirms the feasibility of developing rotigotine transdermal system using novel technology.

Design, Development and Delivery of Rasagiline Mesylate from Monolithic Drug in Adhesive Matrix Patches

The purpose of this research was to prepare and evaluate monolithic drug-in-adhesive type patches of Rasagiline Mesylate (RM) containing penetration enhancer and having seven day wear property. Preformulation studies like solubility in permeation enhancers, compatibility study, transmission study, uptake study and crystallization study of Rasagiline Mesylate in various pressure sensitive adhesive polymers were performed. Transdermal system was prepared by solvent casting method. The effects of various permeation enhancers (Propylene Glycol, Oleic Acid, Isopropyl Palmitate, and lauryl lactate) on the ex-vivo transcutaneous absorption of Rasagiline Mesylate through human cadaver skin were evaluated by modified Franz diffusion cell system. Ex-vivo transcutaneous absorption of prepared transdermal patch was performed using different concentration of Lauryl lactate (3%, 5%, and 7%). In-vitro Adhesion testing (Peel, tack shear etc.) was performed on different dry GSM (Grams per Square Meter) of patch like 80GSM, 100 GSM and 150 GSM. The final transdermal patches were tested for appearance, weight of matrix, thickness, % assay of drug content, in-vitro adhesion testing, cold flow study and ex-vivo skin permeation studies. Based on crystallization study and adhesion testing, Durotak-4098 (14% drug concentration) was selected as pressure sensitive adhesive. Patch containing Lauryl lactate showed highest cumulative permeation compared to other permeation enhancers. The patch containing 5% laurel lactate showed greater transdermal flux (2.36 µg/cm2 /hr). Patch with 150 dry GSM showing promising adhesion properties. Backing film Scotchpak 9723 and release liner Saint Gobain 8310 was selected based on transmission and uptake study of Rasagiline Mesylate. Stability study indicates that developed formulation remains stable. In conclusion, the present research confirms the practicability of developing Rasagiline Mesylate transdermal system.

Bimolecular crystal instability and morphology of bulk heterojunction blends in organic and perovskite solar cells

The in situ crystallization study reveals that size compatibility plays a key role in governing the formation of bimolecular crystals.

Crystallization behavior of citric acid based on solution speciation and growth kinetics

The work reports the crystallization study of citric acid in aqueous solutions, using a large variety of methods. The results are compared to Ostwald's rule of stages, leading to some contradictory results between the experiments and the rule.

Garcinoic Acid Is a Natural and Selective Agonist of Pregnane X Receptor

Pregnane X receptor (PXR) is a master xenobiotic-sensing transcription factor with a key role in drug metabolism and disposition. Its activity regulates a number of physiological processes in the liver and intestine, and it is now a validated target for human diseases associated with inflammation and dysregulation of the immune system. The identification of chemical probes to investigate the therapeutic relevance of the receptor is still highly desired. In fact, currently available PXR ligands are not highly selective and can exhibit toxicity and/or potential off-target effects. In this study, we have identified the naturally-occurring garcinoic acid as a selective and efficient PXR agonist. The properties of garcinoic acid as a specific PXR agonist was demonstrated using different approaches - screening on a panel of nuclear receptors, physical and thermodynamic evaluation of binding affinity, and co-crystallization study. Cytotoxicity assays, transcriptional and functional experiments were carried out in human liver cells, in mouse liver and gut tissue to prove compound activity and target engagement. Taken together, these data support the conclusion that garcinoic acid efficiently activates PXR and may prove to be an amenable lead toward the development of differentially acting PXR regulating compounds.

Garcinoic Acid Is a Natural and Selective Agonist of Pregnane X Receptor

Pregnane X receptor (PXR) is a master xenobiotic-sensing transcription factor with a key role in drug metabolism and disposition. Its activity regulates a number of physiological processes in the liver and intestine, and it is now a validated target for human diseases associated with inflammation and dysregulation of the immune system. The identification of chemical probes to investigate the therapeutic relevance of the receptor is still highly desired. In fact, currently available PXR ligands are not highly selective and can exhibit toxicity and/or potential off-target effects. In this study, we have identified the naturally-occurring garcinoic acid as a selective and efficient PXR agonist. The properties of garcinoic acid as a specific PXR agonist was demonstrated using different approaches - screening on a panel of nuclear receptors, physical and thermodynamic evaluation of binding affinity, and co-crystallization study. Cytotoxicity assays, transcriptional and functional experiments were carried out in human liver cells, in mouse liver and gut tissue to prove compound activity and target engagement. Taken together, these data support the conclusion that garcinoic acid efficiently activates PXR and may prove to be an amenable lead toward the development of differentially acting PXR regulating compounds.