Thermosensitive Injectable Hydrogel for Simultaneous Intraperitoneal Delivery of Doxorubicin and Prevention of Peritoneal Adhesion

Abstract

To improve intraperitoneal chemotherapy and to prevent postsurgical peritoneal adhesion, we aimed to develop a drug delivery strategy for controlled release of a chemotherapeutic drug from the intraperitoneally injected thermosensitive poly(N-isopropylacrylamide)-based hydrogel (HACPN), which is also endowed with peritoneal anti-adhesion properties. Anticancer drug doxorubicin (DOX) was loaded into the hydrogel (HACPN-DOX) to investigate the chemotherapeutic and adhesion barrier effects in vivo. A burst release followed by sustained release of DOX from HACPN-DOX was found due to gradual degradation of the hydrogel. Cell culture studies demonstrated the cytotoxicity of released DOX toward CT-26 mouse colon carcinoma cells in vitro. Using peritoneal carcinomatosis animal model in BALB/c mice with intraperitoneally injected CT-26 cells, animals treated with HACPN-DOX revealed the best antitumor efficacy judging from tumor weight and volume, survival rate, and bioluminescence signal intensity when compared with treatment with free DOX at the same drug dosage. HACPN (or HACPN-DOX) also significantly reduced the risk of postoperative peritoneal adhesion, which was generated by sidewall defect-cecum abrasion in tumor-bearing BALB/c mice, from gross and histology analyses. This study could create a paradigm to combine controlled drug release with barrier function in a single drug-loaded injectable hydrogel to enhance the intraperitoneal chemotherapeutic efficacy while simultaneously preventing postsurgical adhesion.

Keywords: anti-adhesion; anticancer; chemotherapy; doxorubicin; injectable hydrogel; thermosensitive.

Figure 1

(Top) Phase transition behavior from observation of HACPN-DOX (10% (w/v) HACPN containing 1 mg/mL DOX) and 10% (w/v) HACPN solutions at 25 and 37 °C; (Bottom) Scanning electron micrographs of HACPN and HACPN-DOX hydrogels (bar = 20 μm).

Figure 2

In vitro degradation of HACPN (A) and drug release from HACPN-DOX (B). (C) Cytotoxicity of released DOX toward CT-26 cells determined by MTT assays with cell culture medium (control) taken as 100% relative cell viability. * p < 0.01 compared with control, ^# p < 0.01 compared with HACPN.

Figure 3

Gross evaluation of the peritoneal tumors removed from peritoneal carcinomatosis mice treated with 200 μL of saline (control), 200 μL of 10% (w/v) HACPN, 200 μL of 10% (w/v) HACPN-DOX containing 1 mg/mL DOX, or 200 μL of 1 mg/mL DOX. Insets are the peritoneal tumors removed from the mice in each group.

Figure 4

The relative body weight (A) and survival rate (B) of peritoneal carcinomatosis mice treated with 200 μL of saline (control), 200 μL of 10% (w/v) HACPN, 200 μL of 10% (w/v) HACPN-DOX containing 1 mg/mL DOX, or 200 μL of 1 mg/mL DOX.

Figure 5

(A) Intraperitoneal tumor growth of peritoneal carcinomatosis mice (CT-26/Luc cells) was monitored by bioluminescence imaging (BLI). (A) Representative BLI results obtained from mice intraperitoneally injected with 200 μL of saline (control), 200 μL of 10% (w/v) HACPN, 200 μL of 10% (w/v) HACPN-DOX containing 1 mg/mL DOX, or 200 μL of 1 mg/mL DOX at day 0, 7, and 14 using in vivo imaging system (IVIS). (B) The total bioluminescent signal intensity was normalized by that at day 0 to calculate the normalized BLI signal intensity at day 7 and 14 (mean ± SD, n = 8). * p < 0.01 compared with control and HACPN, ^# p < 0.05 compared with DOX.

Figure 6

Gross observation of adhesion formation in peritoneal carcinomatosis mice in the saline (control), HACPN, HACPN-DOX, and DOX groups. The black arrows show adhesion formation between peritoneum and cecum. The black arrowheads indicate the peritoneal tumors while white arrowheads indicate the residual hydrogel.

Figure 7

The hematoxylin and eosin (H&E) staining of tissue sections from peritoneal carcinomatosis mice after saline (control), HACPN, HACPN-DOX, and DOX treatments. Scale bar = 200 μm. Black arrows indicate the adhesion between peritoneum and cecum. ADH = adhesion; AW = abdominal wall; CE = cecum; T = tumor.