This paper describes the implementation of an efficient and accurate multiple scattering parameterization within the LOWTRAN and FASCODE transmittance/radiance models. The parameterization is based on a stream approximation in which the local radiance field needed to evaluate the multiple scattering source function is estimated from the local radiation fluxes. The latter are calculated based on a parameterized two-flux for individual layers and an adding method for combining layers. Because of the line-by-line nature of FASCODE, it is straightforward to implement the multiple scattering treatment. For LOWTRAN, an interface scheme was developed using the k-distribution method to match the multiple scattering approach to the band model calculation of gas absorption. The interface scheme represents the LOWTRAN band model by a sum of pseudomonochromatic calculations. The approach is valid for any band model for which k-distribution parameters can be evaluated. The accuracy of the multiple scattering parameterization has been demonstrated by comparing it with more detailed calculations for a variety of atmospheric conditions. RMS errors in radiance considering all possible viewing angles are <20%. In addition, to insure consistency between models, overlapping LOWTRAN and FASCODE spectral regions are compared. Finally, it is demonstrated that the implemented multiple scattering parameterization corrects LOWTRAN's previous underestimation of path radiance for long horizon paths where multiple scattering is significant.

Over the last several years, continuous manufacturing of pharmaceuticals has evolved from bulk APIs and solid oral dosages into the more complex realm of biologics. The development of continuous downstream processing techniques has allowed biologics manufacturing to realize the benefits (e.g., improved economics, more consistent quality) that come with continuous processing. If relevant processing techniques and principles are selected, the opportunity arises to develop continuous manufacturing designs for additional pharmaceutical products including liposomal drug formulations. Liposome manufacturing has some inherent aspects that make it favorable for a continuous process. Other aspects such as formulation refinement, materials of construction, and aseptic processing need development, but present an achievable challenge. This paper reviews the current state of continuous manufacturing technology applicable to liposomal drug product manufacturing and an assessment of the challenges and potential of this application.

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