Different molecular motions in lyophilized protein formulations as determined by laboratory and rotating frame spin-lattice relaxation times.

The spin-lattice relaxation times in the laboratory and rotating frame (T(1) and T(1rho)) of protons and carbons in lyophilized bovine serum gamma-globulin formulation containing dextran were determined by (1)H solid-state pulsed nuclear magnetic resonance (NMR) and high-resolution (13)C solid-state NMR. The temperature dependence of T(1) and T(1rho) of dextran protons in the lyophilized formulation suggests that the correlation time, tau(c), of the methylene protons in dextran is approximately 10(-6) s at -100 degrees C and 60% relative humidity, and decreases to 10(-7) s at 0 degrees C. When temperature is increased from 0 degrees C, the increased motion of the methylene groups is reflected in T(1), but is too fast to be observed by changes in T(1rho). Thus, the motion of the methine groups rather than the methylene groups begins to be reflected in T(1rho). The correlation time of the methine protons as determined by T(1rho) was of the same order as that of the methine carbons as determined by T(1rho). As the temperature is increased past the glass/rubber transition temperature, both the methylene and methine motions are greatly enhanced, resulting in much shorter T(1) and T(1rho) relaxation times.