Dissolution profiles of BCS class II drugs generated by the gastrointestinal simulator alpha has an edge over the compendial USP II method.

The poor water solubility of orally administered drugs leads to low dissolution in the GI tract, resulting to low oral bioavailability. Traditionally, in vitro dissolution testing using the compendial dissolution apparatuses I and II has been the gold-standard method for evaluating drug dissolution and assuring drug quality. However, these methods don't accurately represent the complex physiologies of the GI tract, making it difficult to predict in vivo behavior of these drugs. In this study, the in vivo predictive method, gastrointestinal simulator alpha (GIS-α), was used to study the dissolution profiles of commercially available BCS Class II drugs, danazol, fenofibrate, celecoxib, and ritonavir. This biorelevant transfer method utilizes multiple compartments alongside peristaltic pumps, to effectively model the transfer of material in the GI tract. In all cases, the GIS-α with biorelevant buffers gave superior dissolution profiles. In silico modeling using GastroPlusTM yielded better prediction when utilizing the results from the GIS-α as input compared to the dissolution profiles obtained from the USP II apparatus. This gives the GIS-α an edge over compendial methods in generating drug dissolution profiles and is especially useful in the early stages of drug and formulation development. This information gives insight into the dissolution behavior and potential absorption patterns of these drugs which can be crucial for formulation development, as it allows for the optimization of drug delivery systems to enhance solubility, dissolution, and ultimately, bioavailability.

Synergy between the clavanins as a weapon against multidrug-resistant Enterobacter cloacae.

Finding new antibiotics that can act synergistically with each other offers many benefits such as lower dosages used for each drug, improved pathogen clearance, and ability to act against multi-drug resistant strains. In this study, six peptides isolated from the tunicate Styela clava were evaluated for their synergistic interaction using the checkerboard assay and the time kill kinetics assay. Using two different tests, we report synergy between clavanin D and clavaspirin in both tests and synergy between clavanin A and B only in the checkerboard test when used against the multidrug resistant E. cloacae 0136. This work demonstrates the possible cooperativity between homologous AMPs from a single organism and the advantage of using two susceptibility tests instead of one when testing synergistic combinations.

Exploring synergy and its role in antimicrobial peptide biology.

Antimicrobial peptides will be an essential component in combating the escalating issue of antibiotic resistance. Identifying synergistic combinations of two or more substances will increase the value of these peptides further. Several potential pitfalls in conducting synergy testing with peptides are discussed in detail. As case studies, we describe observations of AMP synergy with peptides, antibiotics, and metal ions as well as some of the mechanistic details that have been uncovered. The Bliss and Loewe models for synergy are presented prior to recommending protocols for conducting checkerboard, minimal inhibitory concentration, and time-kill assays. Establishing mechanisms of action and exploring the potential for resistance will be crucial to translate these studies into the clinic.