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Intravenous vs intraperitoneal sensitizer: implications for intraperitoneal photodynamic therapy
R R Perry1, P D Smith, S Evans
1Thoracic Oncology Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Photochemistry and Photobiology
|March 1, 1991
Summary
Intraperitoneal administration of Photofrin II for photodynamic therapy (PDT) in peritoneal carcinomatosis showed comparable tumor sensitizer levels to intravenous administration. This study determined optimal parameters for future PDT research.
Area of Science:
- Oncology
- Photochemistry
- Pharmacokinetics
Background:
- Peritoneal carcinomatosis presents a significant clinical challenge.
- Photodynamic therapy (PDT) is a promising treatment modality.
- Limited data exists on sensitizer distribution and optimal PDT parameters for intra-abdominal applications.
Purpose of the Study:
- To evaluate sensitizer distribution and pharmacokinetics following intraperitoneal (IP) versus intravenous (IV) administration of Photofrin II.
- To determine the maximal tolerated light dose for intra-abdominal PDT in a mouse model.
- To inform the design of future large-scale animal trials for intra-abdominal PDT.
Main Methods:
- A mouse peritoneal tumor model was utilized.
- Photofrin II (10 mg/kg) was administered IP or IV.
- Sensitizer levels in tumor and normal tissues were measured at various time points (3, 24, 48, 72 h).
- Maximal tolerated light dose (630 nm) was determined.
Main Results:
- Both IP and IV administration yielded equivalent tumor sensitizer levels.
- IP administration resulted in slower sensitizer elimination (T1/2 = 113.6 h) compared to IV (T1/2 = 60.6 h).
- IP administration led to higher tumor-to-organ (liver, kidney) sensitizer ratios at 24 and 72 h.
- No significant difference in PDT toxicity or mortality was observed between administration routes.
- The maximal tolerated light dose was 1.04 J/cm².
Conclusions:
- Route of administration for Photofrin II impacts sensitizer pharmacokinetics and tissue distribution.
- IP administration may offer advantages in maintaining higher tumor sensitizer levels relative to certain organs.
- The determined maximal tolerated light dose and pharmacokinetic data are crucial for designing future intra-abdominal PDT studies.