Regenerated Cellulose Capsules for Controlled Drug Delivery, Part 2: Modulating Membrane Permeability by Incorporation of Depolymerized Cellulose and Altering Membrane Thickness

Visualized analysis and evaluation of simultaneous controlled release of metformin hydrochloride and gliclazide from sandwiched osmotic pump capsule

The aim of this study was to develop the Metformin Hydrochloride and Gliclazide (MH-GZ) sandwiched osmotic pump capsule which could overcome the problems associated with short half-life and burst release. The system could deliver drugs with different solubility simultaneously at zero-order rate, in which MH-GZ were filled in both sides of the push layer respectively. The single factor and orthogonal test were employed to obtain the optimized formulation with the evaluation index of similarity factor (ƒ₂). R language was used to visualized analyze the main influence factors of drug release and their correlations. Pharmacokinetic study was performed in beagle dogs compared to the marketed conventional product, which showed decreased C_max, prolonged T_max, and improved bioavailability, independent of pH and agitational speed but related to osmotic pressure differences across the semi permeable membrane. The designed sandwiched osmotic pump capsule proposed a promising substitute for the marketed product for the treatment of type 2 diabetes.

A Novel Colon-Specific Osmotic Pump Capsule of Panax notoginseng Saponins (PNS): Formulation, Optimization, and In Vitro-In Vivo Evaluation

In the current study, a novel colon-specific osmotic pump capsule of Panax notoginseng saponins was developed to achieve colon-specific release, a zero-order, thus to promote the efficacy of Panax notoginseng saponins. The capsule was assembled using a semi-permeable capsule shell with contents including Panax notoginseng saponins, sodium chloride (NaCl), and Ludipress. The semipermeable membrane was made of cellulose acetate (CA), along with polyethylene glycol (PEG) 6000 for flexibility and strength, and Eudragit® S100 for colon-specific targeting. The in vitro dissolution test showed an approximately zero-order release of Panax notoginseng saponins over 12 h at pH 7.8 through the pores on the membrane. Meanwhile, the drug release from the optimal formulation was found to be independent of equipment type or agitation speed. Rather, it depended on mainly the osmotic pressure of the dissolution media. The in vivo test in beagle dogs demonstrated that the relative bioavailability of the current system was 487.42% in comparison to that of the marketed product, yet with a prolonged retention time. The novel controlled delivery system for Panax notoginseng saponins in the current study utilizing colon-specific and osmotic pump system therefore offered the advantages of avoiding stomach and enteric irritation, reducing dosage frequency, minimizing the drug fluctuation in plasma, and improving its oral bioavailability.

Regenerated cellulose capsules for controlled drug delivery: Part IV. In-vitro evaluation of novel self-pore forming regenerated cellulose capsules

In the present work, the release mechanisms of active pharmaceutical ingredients (APIs) enclosed in self-pore forming regenerated cellulose (RC) two-piece hard shell capsules are described. The RC capsules were fabricated using a modified dip-coating approach, which yielded an assembled dosage form that was equivalent in size and shape to a conventional gelatin two-piece hard shell capsule. Drug release characteristics from RC capsules were evaluated using potassium chloride, diphenhydramine hydrochloride, tramadol hydrochloride, niacinamide, acetaminophen and ketoprofen as model APIs. The RC capsules act as a barrier coated reservoir device that releases the enclosed API at a zero order release rate. When comparing all the API's release behavior from RC capsules, a power-law relationship was observed between their zero-order release rates and their respective aqueous solubilities. Osmotic as well as diffusive mechanisms are involved in the release of the enclosed API. The osmotic mechanism's contribution to zero order release rate increases as the aqueous solubility of the tested APIs inside the capsule increases. The osmotic mediated flux and the apparent diffusivity of the APIs through the capsule wall is a competitive process and the osmotic mediated flux of the enclosed API begins to override its diffusivity through the capsule wall as the API solubility increases. This behavior is attributed to the wide range of pore sizes observed in RC membranes, from our prior analysis. The fluid permeability analysis shows that the RC capsules presented in this work may be better suited for osmotic drug delivery applications than conventional encapsulated systems described in the literature.