Development and Evaluations of Aceclofenac Microcapsules for Colon-Targeted Delivery: An In Vitro Study MUHAMMAD FAROOQ Faculty of Pharmacy, The University of Lahore, Lahore, Pakistan MAHMOOD AHMAD, ASADULLAH MADNI Faculty of Pharmacy & Alternative Medicine, The Islamia University of Bahawalpur 63100, Pakistan MUHAMMAD HANIF, MUHAMMAD RIZWAN KHAN Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan Correspondence to: Muhammad Farooq; e-mail: muhammad.farooq@pharm.uol.edu.pk. Received: July 16, 2014 Accepted: September 20, 2014 ABSTRACT: Microcapsules of aceclofenac with pH-dependent release properties for achieving targeted delivery to colon were developed. A solvent evaporation technique was adopted for microcapsules preparation using Eudragit RS 100 as a retardant polymer. The microcapsules were found free flowing, whitish, and spherical in shape. The entrapment efficacies of microcapsules were 95.73, 85.67, and 84% for F1 (1:1), F2 (1:2), and F3 (1:3), respectively. The particle size was in the range of 12 ± 2.48 to 32 ± 2.20 μm. The X-ray diffraction and Fourier transforms infrared (FTIR) studies of prepared microcapsules illustrated that there was no interaction between drug and polymer. The dissolution performed in three different pH media (1.2, 6.8, and 7.4) at 37 ± 0.5°C elucidates negligible release at pH 1.2 for 2 h but changing the pH from 1.2 to 6.8, showed burst release after 4 h and then demonstrated a constant release rate at 7.4 pH. The time for half-life of microcapsules showed that drug release from F1 microcapsules was quicker than F2 and F3. The time for half-life of capsule filled microcapsules was 15.54, 17.40, and 20.08 h, respectively. The formulated microcapsules do not show the release in gastric medium but released at phosphate buffer pH 6.8 and 7.4. C  2014 Wiley Periodicals, Inc. Adv Polym Technol 2014, 00, 21482; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21482 KEY WORDS: Aceclofenac, Colon-targeted delivery, FTIR, Microcapsules, Solvent evaporation Introduction T he colonic drug delivery system has achieved great sig- nificance in the treatment of local diseases of colon such as ulcerative colitis, colorectal cancer, inflammatory bowel dis- ease, Crohn’s disease, and irritable bowel syndrome. 1 The colon is an attractive site where poorly absorbed drug molecule may have enhanced bioavailability. The colon drug delivery have sev- eral therapeutic advantages such as neutral pH, longer transit time, and reducing extensive first pass metabolism of steroids, Preventing the gastric irritation created by nonsteroidal anti- inflammatory drugs (NSAIDS), delayed the drug release. The successful management of drugs to the colon requires safety from drug degradation and release in stomach and small intes- tine than promising abrupt release in the proximal colon. The simplest method of targeting drugs to colon is by application of a thicker layer of conventional enteric coating; pH-sensitive polymers such as Eudragit RS100 or Eudragit RL100 are suit- able for achieving colonic drug delivery. 2 Different types of ap- proaches have been utilized for colon drug delivery. Most of these consume physiological properties of gastroretentive in- testinal tract (GIT) and colon such as pH of GIT, transit time through small intestine, luminal pressure of colon, and micro- bial flora in the colon. The pH of terminal ileum and colon is higher than in any other part of the GIT. Therefore, a dosage form that disintegrates preferentially at higher pH levels has higher potential for site-specific delivery into colon due to re- striction of change in luminal pH. The coating of microcapsules, nanoparticles, and granules with different pH-sensitive poly- mers produces the targeted release formulations and also pro- vides protection from gastric fluids. The pH-dependent system has advantages due to the highest pH value of colon to trigger the drug release. The selected polymers to colon targeting should be capable of resisting the pH of the stomach and small intestine. The release of drug from a dosage form should be after a fixed Advances in Polymer Technology, Vol. 00, No. 0, 2014, DOI 10.1002/adv.21482 C  2014 Wiley Periodicals, Inc. 21482 (1 of 8)