Polymer Conjugation

The "PEGylation" of peptides and proteins has proved to be a highly successful means of extending the circulating half-life of a number of proteins after injection. Several are now approved or close to approval, including PEGylated interferon alfa (PEG Intron®, Pegasys®), pegademase, pegasparaginase, and PEGylated rhG-CSF (SD/01). This general interest has not translated to any significant product development for pulmonary delivery, and few feasibility studies have been conducted. PEGylated superoxide dimutase has proved to be a successful oxygen-radical scavenger in a rodent model of oxygen-induced toxicity [106], while PEGylated G-CSF can generate an extended neutropenic response despite limited pulmonary absorption [107]. PEG conjugates of ovalbumin have also been aerosolized to dogs as "desensitizers." Bronchocon-striction to subsequent ovalbumin aerosol challenges were completely blocked [108]. There actually seems no clear reason for not pursuing the use of PEGylation in clinical studies. Two-week toxicity studies in animals using PEG have not exhibited any pathological conditions or responses that would warrant the apparent reticence [109]. Furthermore, where there is a need to restrict absorption and to limit systemic side effects (e.g., certain antibiotics or cytokines), this approach may have merit as a targeted delivery system.

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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