Autotemplate Microcapsules of CaCO₃/Pectin and Nonstoichiometric Complexes as Sustained Tetracycline Hydrochloride Delivery Carriers

Abstract

New types of composites were obtained by an autotemplate method for assembling hollow CaCO capsules by using pH-sensitive polymers. Five pectin samples, which differ in the methylation degree and/or amide content, and some nonstoichiometric polyelectrolyte complex dispersions, prepared with the pectin samples and poly(allylamine hydrochloride), were used to control the crystal growth. The morphology of the composites was investigated by scanning electron microscopy, and the polymorphs characteristics were investigated by FTIR spectroscopy. The presence of the polymer in the composite particles was evidenced by X-ray photoelectron spectroscopy, particle charge density, and zeta-potential. The new CaCO/pectin hollow capsules were tested as a possible matrix for a tetracycline hydrochloride carrier. The kinetics of the drug release mechanism was followed using Higuchi and Korsmeyer-Peppas mathematical models.

High-efficiency freezing-induced loading of inorganic nanoparticles and proteins into micron- and submicron-sized porous particles

“…The encapsulation of actual drugs instead of model fluorescent dyes or fluorescently labeled polymers has been reported. Examples of encapsulated substances include the anticancer agents cisplatin 12 and doxorubicin 13 , tetracycline hydrochloride 14 , and photodynamic dyes 15 . Most published articles dealing with vaterite particles have reported in vitro studies of the uptake efficiency, toxicity (cell viability), and the kinetic release profiles of drugs 13,16,17 .…”

Complex calcium carbonate/polymer microparticles as carriers for aminoglycoside antibiotics

“…When amidated pectin samples was used to produce the NPECs (PCT53_A21), for NPECs with an excess of positively charged polyelectrolyte molecules (n + /n À ¼ 1.2) the surface net charge was only slightly affected by the variation of the pH value. 20 Thus, the composites used in this study are stable at pH higher than 5 and slightly decompose at lower pH, the complete decomposition taking place around pH ¼ 3. Therefore, the studied composites are suitable for prolong drug release at pH higher than 3.5 (ophthalmic and transdermal applications) and for rapid release at pH lower than 3 (stomach).…”

“…Aer mixing, the formed dispersions were stirred 60 min and were characterized and used in composite preparation aer 24 h. The composite microcapsules were obtained through co-precipitation of 0.05 M Na 2 CO 3 and 0.1 M CaCl 2 solutions in the presence of pectins or NPEC dispersions for 8 hours at room temperature, as described in our previous paper. 20 The shape and surface of the new particles were examined with an Environmental Scanning Electron Microscope type Quanta 200 using secondary electron (SE2) detector and Scanning Electron Microscope type Ultra plus (Carl Zeiss NTS) using energy selective backscattered (ESB) electron detector. To avoid electrostatic charging, the samples were coated with platinum or gold.…”

Calcium Carbonate and Poly(2-Acrylamido-2-Methylpropanesulfonic Acid-Co-Acrylic Acid). A Review

“…Mihai et al 36 proposed a pathway for the formation of CaCO 3 capsules in the presence of pectins and nonstoichiometric polyelectrolyte complexes. The process involves the following steps: (1) interaction of calcium ions with ionic or ionizable groups along the polymer chain or on uncomplexed nanoparticle fragments with gelforming microparticles and crystallization of calcium carbonate in calcium rich areas; (2) growth of calcium carbonate crystals with microparticle formation (in the first minute of crystallization); (3) dissolution of the less stable (amorphous and vaterite) CaCO 3 fractions mainly by dissolving the core of the microparticles; (4) secondary nucleation of the calcite crystalline polymorph on the external surface; (5) progressive increase of the thickness of the crystalline wall as the core is emptied, yielding hollow microspheres.…”

“…Even if there are numerous studies on polyanions control of CaCO 3 growth, the use of nonstoichiometric polyelectrolyte complexes (NPEC) as templates for controlling CaCO 3 crystals growth has been reported up to now only by our group. 36,76,81 Polyelectrolyte complexes (PECs) are obtained by mixing aqueous solutions of oppositely charged polymers. 82 PECs are of interest due to their facile preparation and responsiveness to environmental stimuli.…”