Formulation and in vitro-in vivo evaluation of black raspberry extract-loaded PLGA/PLA injectable millicylindrical implants for sustained delivery of chemopreventive anthocyanins

Pharm Res. 2010 Apr;27(4):628-43. doi: 10.1007/s11095-009-0038-5. Epub 2010 Feb 11.


Purpose: The objective of this study was to formulate and evaluate freeze-dried black raspberry (FBR) ethanol extract (RE) loaded poly(DL-lactic-co-glycolic acid) (PLGA) and poly(DL-lactic acid) (PLA) injectable millicylindrical implants for sustained delivery of chemopreventive FBR anthocyanins (cyanidin-3-sambubioside (CS), cyanidin-3-glucoside (CG) and cyanidin-3-rutinoside (CR)).

Methods: Identification and quantitation of CS, CG, and CR in RE was performed by mass spectroscopy and HPLC. RE:triacetyl-beta-cyclodextrin (TA-beta-CD) inclusion complex (IC) was prepared by a kneading method and characterized by X-ray diffraction (XRD), nuclear magnetic resonance spectroscopy (NMR) and UV-visible spectroscopy. RE or RE:TA-beta-CD IC-loaded PLGA or PLA implants were prepared by a solvent extrusion method. In vitro and in vivo controlled release studies were conducted in phosphate-buffered saline Tween-80 (pH 7.4, 37 degrees C) and after subcutaneous administration in male Sprague-Dawley rats, respectively. Anthocyanins were quantified by HPLC at 520 nm.

Results: The content of CS, CG, and CR in RE was 0.2, 1.5, and 3.5 wt%, respectively. The chemical stability of anthocyanins in solution was determined to be pH-dependent, and their degradation rate increased with an increase in pH from 2.4 to 7.4. PLGA/PLA millicylindrical implants loaded with 5 or 10 wt% RE exhibited a high initial burst and short release duration of anthocyanins (35-52 and 80-100% CG + CR release after 1 and 14 days, respectively). The cause for rapid anthocyanins release was linked to higher polymer water uptake and porosity associated with the high osmolytic components of large non-anthocyanin fraction of RE. XRD, (1)H NMR and UV-visible spectroscopy indicated that the non-anthocyanin fraction molecules of RE formed an IC with TA-beta-CD, decreasing the hydrophilicity of RE. Formation of an IC with hydrophobic carrier, TA-beta-CD, provided better in vitro/in vivo sustained release of FBR anthocyanins (16-24 and 97-99% CG + CR release, respectively, after 1 and 28 days from 20 wt% RE:TA-beta-CD IC/PLA implants) over 1 month, owing to reduced polymer water uptake and porosity.

Conclusion: PLA injectable millicylindrical implants loaded with RE:TA-beta-CD IC are optimal dosage forms for 1-month slow and continuous delivery of chemopreventive FBR anthocyanins.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anthocyanins / administration & dosage*
  • Anthocyanins / analysis
  • Anthocyanins / pharmacology
  • Anthocyanins / therapeutic use*
  • Antineoplastic Agents, Phytogenic / administration & dosage*
  • Antineoplastic Agents, Phytogenic / analysis
  • Antineoplastic Agents, Phytogenic / pharmacology
  • Antineoplastic Agents, Phytogenic / therapeutic use*
  • Delayed-Action Preparations / chemistry*
  • Fruit / chemistry*
  • Injections
  • Lactic Acid / chemistry
  • Male
  • Polyesters
  • Polyglycolic Acid / chemistry
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polymers / chemistry
  • Prostheses and Implants
  • Rats
  • Rats, Sprague-Dawley
  • Rosaceae / chemistry*


  • Anthocyanins
  • Antineoplastic Agents, Phytogenic
  • Delayed-Action Preparations
  • Polyesters
  • Polymers
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyglycolic Acid
  • Lactic Acid
  • poly(lactide)