A novel pulsatile drug delivery system based on the physiochemical reaction between acrylic copolymer and organic acid: in vitro and in vivo evaluation

Preparation, Characterization and In Vitro / In Vivo Evaluation of Oral Time-Controlled Release Etodolac Pellets

The objective of this study was to prepare time-controlled release etodolac pellets to facilitate drug administration according to the body's biological rhythm, optimize the drug's desired effects, and minimize adverse effects. The preparation consisted of three laminal layers from center to outside: the core, the swelling layer, and the insoluble polymer membrane. Factors influenced the core and the coating films were investigated in this study. The core pellets formulated with etodolac, lactose, and sodium carboxymethyl starch (CMS-Na) were prepared by extrusion-spheronization and then coated by a fluidized bed coater. Croscarmellose sodium (CC-Na) was selected as the swelling agent, and ethyl cellulose (EC) as the controlled release layer. The prepared pellets were characterized by scanning electron microscopy and evaluated by a dissolution test and a pharmacokinetic study. Compared with commercial available capsules, pharmacokinetics studies in beagle dogs indicated that the prepared pellets release the drug within a short period of time, immediately after a predetermined lag time. A good correlation between in vitro dissolution and in vivo absorption of the pellets was exhibited in the analysis.

Design of a Time-Controlled Pulsatile Release System for Propranolol Using the Dry-Coated Method: In Vitro and In Vivo Evaluation

The objective of this study was to design a time-controlled pulsatile release (TCPR) system containing propranolol (PNH) as an active pharmaceutical ingredient. Here, the developed dosage forms were coated with hydroxypropyl-methylcellulose (HPMC) and other excipients as barrier layer using dry-coated technology. The influence of HPMC, microcrystalline cellulose (MCC), and lactose in the outer coating and the coating weight on drug release were investigated. Then, a three-factor, five-level central composite design (CCD) and response surface method were used to optimize the formula of the coating. After data processing, the optimal prescription was found to be as follows: HPMC E50(X₁) 86.2 mg, MCC(X₂) 43.8 mg, and lactose (X₃) 21.3 mg in the coating. Moreover, the in vitro tests showed that the optimized formulation of TCPR had a lag time of 4 h followed by a 4-h drug release. Also, determination of the extent of erosion of the TCPR tablets revealed that the lag time is related to the coating erosion speed. The in vivo test in beagle dogs and comparison of the parameters for the TCPR tablets and reference preparations showed significant differences for T_max (7.83 ± 0.408 and 2 ± 0.00) and C_max (185.45 ± 28.561 and 587 ± 45.27 ng/ml) but no significant differences in the AUC_0-∞ (1757.876 ± 208.832 and 1779.69 ± 229.02 ng h/ml). These results demonstrated that the TCPR tablets successfully prolonged the lag time and controlled the release of propranolol.

Controlled and Sequential Delivery of Fluorophores from 3D Printed Alginate-PLGA Tubes

Controlled drug delivery systems, that include sequential and/or sustained drug delivery, have been utilized to enhance the therapeutic effects of many current drugs by effectively delivering drugs in a time-dependent and repeatable manner. In this study, with the aid of 3D printing technology, a novel drug delivery device was fabricated and tested to evaluate sequential delivery functionality. With an alginate shell and a poly(lactic-co-glycolic acid) (PLGA) core, the fabricated tubes displayed sequential release of distinct fluorescent dyes and showed no cytotoxicity when incubated with the human embryonic kidney (HEK293) cell line or bone marrow stromal stem cells (BMSC). The controlled differential release of drugs or proteins through such a delivery system has the potential to be used in a wide variety of biomedical applications from treating cancer to regenerative medicine.

Neoglycoenzyme-Gated Mesoporous Silica Nanoparticles: Toward the Design of Nanodevices for Pulsatile Programmed Sequential Delivery

We report herein the design of a stimulus-programmed pulsatile delivery system for sequential cargo release based on the use of a lactose-modified esterase as a capping agent in phenylboronic acid functionalized mesoporous silica nanoparticles. The dual-release mechanism was based on the distinct stability of the cyclic boronic acid esters formed with lactose residues and the long naturally occurring glycosylation chains in the modified neoglycoenzyme. Cargo delivery in succession was achieved using glucose and ethyl butyrate as triggers.