Hydroxypropyl methylcellulose acetate succinate-based spray-dried dispersions: an overview.

Spray-dried dispersions (SDDs) of low-solubility drugs have been prepared using the polymer hydroxypropyl methylcellulose acetate succinate (HPMCAS). For a variety of drug structures, these SDDs provide supersaturation in in vitro dissolution determinations and large bioavailability increases in vivo. In bile-salt/lecithin in vitro solutions, these SDDs provide amorphous drug/polymer colloids and an increased concentration of free drug and drug in micelles relative to crystalline or amorphous drug.

Long holographic lifetimes in bacteriorhodopsin films.

The D85N genetic variant of bacteriorhodopsin (BR) displays a nearly permanent lifetime of the photochromic P(490) state. We present pump-probe measurements that demonstrate this behavior. However, diffraction efficiency measurements made from holograms recorded in a hydrated D85N film show markedly different decay behavior, suggesting that a molecular diffusion process is occurring in the film.

Measurements of holographic properties of bacteriorhodopsin films.

Several different bacteriorhodopsin (BR) films are characterized with respect to general holographic properties. Experimental measurements include diffraction efficiency and sensitivity as functions of the writing intensity and grating frequency, hologram thermal-decay behavior, diffraction efficiency as a function of the grating tilt within the film and the modulation depth, and estimates of the refractive-index change from the diffraction-efficiency data. The films studied include those made from wildtype BR and the genetic variants D96N and D96N/T46V.

Red-shifted photochromic behavior of a bacteriorhodopsin film made from the L93T genetic variant.

We present experimental results demonstrating the red-shifted photochromic behavior of a gelatin film made from L93T, a genetic variant of bacteriorhodopsin. The red shift of the absorbance spectrum on illumination with visible light is due to a short M-state lifetime and a longer-lived O state whose absorption peaks at 610 nm. Pump-probe measurements show the O state to have a lifetime of approximately 2.

Experimental determination of number-phase uncertainty relations.

An experimental determination of the uncertainty product for the phase and photon number of a mode of the electromagnetic field is performed. The expectation value of the commutator that sets the lower bound for the uncertainty product is also determined experimentally. This is accomplished by using optical homodyne tomography to measure the density matrix of a small-photon-number coherent state.