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Figure 5 Erythromycin structure and position of O-methylation for obtaining increased lung uptake.

Erythromycin A

Figure 5 Erythromycin structure and position of O-methylation for obtaining increased lung uptake.

Budesonide is used as a 1:1 mixture of the 22R- and 22S-epimers.) Budesonide is not metabolized in lung tissue and is slowly released from lung to the systemic circulation. However, it is rapidly metabolized to the 23-hydroxylated 22S-epimer and 16a-hydroxyprednisolone, which is selectively formed from the 22R-epimer. The rapid inactivation of systemic budesonide by the liver minimizes the potential for systemic side effects [120-123]. In isolated lung perfusion studies, a difference in the distribution between lung tissue and perfusion medium for the two epimers of budesonide was found. Interestingly, the pharmacody-namically more potent epimer 22R showed an uptake in lung tissue that was 1.4 times higher than that of epimer 22S. This property may be due to the fact that epimer 22R is less water soluble than epimer 22S [123].

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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