rosin and Foreign-Body-Reaction

The purpose of this study was to investigate the in vitro-in vivo degradation and tissue compatibility of three novel biopolymers viz. polymerized rosin (PR), glycerol ester of polymerized rosin (GPR) and pentaerythritol ester of polymerized rosin (PPR) and study their potential as implant matrix for the delivery of ciprofloxacin hydrochloride. Free films of polymers were used for in vitro degradation in PBS (pH 7.4) and in vivo in rat subcutaneous model. Sample weight loss, molecular weight decline, and morphological changes were analyzed after periodic intervals (30, 60, and 90 days) to monitor the degradation profile. Biocompatibility was evaluated by examination of the inflammatory tissue response to the implanted films on postoperative days 7, 14, 21, and 28. Furthermore, direct compression of dry blends of various polymer matrices with 20%, 30%, and 40% w/w drug loading was performed to investigate their potential for implant systems. The implants were characterized in terms of porosity and ciprofloxacin release. Biopolymer films showed slow rate of degradation, in vivo rate being faster on comparative basis. Heterogeneous bulk degradation was evident with the esterified products showing faster rates than PR. Morphologically all the films were stiff and intact with no significant difference in their appearance. The percent weight remaining in vivo was 90.70 +/- 6.2, 85.59 +/- 5.8, and 75.56 +/- 4.8 for PR, GPR, and PPR films respectively. Initial rapid drop in Mw was demonstrated with nearly 20.0% and 30.0% decline within 30 days followed by a steady decline to nearly 40.0% and 50.0% within 90 days following in vitro and in vivo degradation respectively. Biocompatibility demonstrated by acute and subacute tissue reactions showed minimal inflammatory reactions with prominent fibrous encapsulation and absence of necrosis demonstrating good tissue compatibility to the extent evaluated. All implants showed erosion and increase in porosity that affected the drug release. Increase in drug loading significantly altered the ciprofloxacin release in extended dissolution studies. PPR produced drug release >90% over a period of 90 days promising its utility in implant systems. The results demonstrated the utility of novel film forming biopolymers as implant matrix for controlled/sustained drug delivery with excellent biocompatibility characteristics.

Topics: Animals; Anti-Bacterial Agents; Biopolymers; Biotransformation; Chemistry, Pharmaceutical; Ciprofloxacin; Delayed-Action Preparations; Drug Implants; Foreign-Body Reaction; Glycerides; Male; Materials Testing; Microscopy, Electron, Scanning; Molecular Weight; Porosity; Propylene Glycols; Rats; Rats, Wistar; Resins, Plant; Solubility; Subcutaneous Tissue; Time Factors

Tissue reaction to gutta-percha was studied using subcutaneously implanted Teflon cages in guinea pigs. Gutta-percha was tested in three forms: (i) as large particles prepared by dividing gutta-percha cones into pieces, (ii) as fine particles prepared by ball-milling of gutta-percha, and (iii) as particles produced by dissolving gutta-percha in rosin-chloroform. Gutta-percha evoked two distinct types of tissue response. The large pieces were well encapsulated and the surrounding tissue was free of inflammation. The fine particles evoked an intense, localized tissue response, characterized by the presence of macrophages and multinucleated giant cells. The rosin-chloroform treated gutta-percha induced a similar tissue reaction to that observed with the fine particles of gutta-percha. In addition, cell remnants were present in association with the material, which indicates an initial toxicity to rosin-chloroform treated gutta-percha. These results show that the size and surface character of gutta-percha can determine the type of tissue reaction to the material. The accumulation of macrophages around gutta-percha may be an important factor in the impairment of healing of periapical lesions when teeth are root filled with excess material.

Topics: Animals; Connective Tissue; Diffusion Chambers, Culture; Foreign-Body Reaction; Giant Cells; Guinea Pigs; Gutta-Percha; Macrophages; Male; Microscopy, Electron; Particle Size; Resins, Plant