The Relationship between the Drug Delivery Properties of a Formulation of Teriparatide Microneedles and the Pharmacokinetic Evaluation of Teriparatide Administration in Rats.

PURPOSE: Teriparatide is an effective drug for the treatment of osteoporosis. This study examines the relationship between the drug delivery properties of the solid formulation with teriparatide and the pharmacokinetic properties of teriparatide in vivo. METHODS: Teriparatide microneedles with different dissolution rates were prepared using sucrose and carboxymethylcellulose (CMC). There were three aspects of this study: (1) The dissolution rate of teriparatide from both formulations (sucrose and CMC) was measured in vitro. (2) After administration into porcine skin ex vivo, the diffusion rate of FITC-dextran was observed using a confocal microscope. (3) Pharmacokinetic studies were performed in rats and pharmacokinetic data compared with the release rate and the diffusion pattern. RESULTS: In the in vitro dissolution experiment, 80% of teriparatide was released within 30 min from the CMC MNs, whereas 80% of teriparatide was released within 10 min from the sucrose MNs. After 30 min, the fluorescence intensity on the surface of the MNs was 40% of the initial intensity for sucrose MNs and 90% for CMC MNs. In the pharmacokinetic study, the Cmax values of the CMC and sucrose MNs were 868 pg/mL and 6809 pg/mL, respectively, and the AUClast values were 6771 pg*hr/mL for the CMC MNs and 17,171 pg*hr/mL for the sucrose MNs. CONCLUSIONS: When teriparatide is delivered into the skin using microneedles, the release rate from the solid formulation determines the drug's pharmacokinetic properties. The diffusion pattern of fluorescence into the skin can be used to anticipate the pharmacokinetic properties of the drug.

Sol-gel-adsorbent-coated extraction needles to detect volatile compounds in spoiled fish.

Volatile compounds generated by fish spoilage were investigated by an inside-needle microextraction method followed by gas chromatography with flame ionization detection and gas chromatography with mass spectrometry. The inside of a needle was coated with an adsorbent to extract the target analytes from the headspace of the sample. The examined adsorbents included ß-cyclodextrin, polystyrene resin cross-linked with 1% divinylbenzene, and polyethylene glycol mixed with polydimethylsiloxane. The investigated volatile compounds generated by fish spoilage were acetone, 2-butanone, 2-butanol, 2-propanol, dimethyl disulfide, acetic acid, and benzaldehyde. The analysis conditions for the sorption and desorption processes were optimized. Each optimized condition was validated by determining the limit of detection and the limit of quantitation from the calibration curves, as well as the recovery, reproducibility, and concentration factors. As a result, all of the fabricated needles afforded successful recoveries, above 90%, with relative standard deviations below 10%. In particular, cyclodextrin and polystyrene resin cross-linked with 1% divinylbenzene mixed with polydimethylsiloxane show good sensitivities and concentration factors for the standard volatile compounds. The storage of fresh mackerel and salted mackerel at room temperature for 14 days caused the concentrations of dimethyl disulfide and acetic acid to significantly increase while those of acetone, 2-butanone, 2-propanol, and 2-butanol changed only slightly.

Electronically Stabilized Copoly(Styrene-Acrylic Acid) Submicrocapsules Prepared by Miniemulsion Copolymerization.

This work reports the preparation and characterization of poly(styrene-acrylic acid) (St/AA) submicrocapsules by using the miniemulsion copolymerization method. AA was introduced to miniemulsion polymerization of St to increase the zeta potential and the resulting electrostatic stability of St/AA submicrocapsules. Phytoncide oil was adopted as the core model material. Miniemulsion copolymerization of St and AA was conducted at a fixed monomer concentration (0.172 mol) with a varying monomer feed ratio [AA]/[St] (0.2, 0.25, 0.33, 0.5, and 1.0). Concentrations of initiator (azobisisobutyronitrile; 1.0 × 10-3, 2.0 × 10-3, 3.0 × 10-3, and 4.0 × 10-3 mol/mol of monomer) and surfactant (sodium dodecyl sulfate; 0.6 × 10-3, 1.0 × 10-3, and 1.4 × 10-3 mol) were also controlled to optimize the miniemulsion copolymerization of St and AA. Dynamic light scattering and microscopic analyses confirmed the optimum condition of miniemulsion copolymerization of St and AA. Long-term colloidal stability of aqueous St/AA submicrocapsule suspension was evaluated by using TurbiscanTM Lab. In this work, the optimum condition for miniemulsion copolymerization of St and AA was determined ([AA]/[St] = 0.33; [SDS] = 1.0 × 10-3 mol; [AIBN] = 2.0 × 10-3 mol/mol of monomer). St/AA submicrocapsules prepared at the optimum condition (392.6 nm and -55.2 mV of mean particle size and zeta potential, respectively) showed almost no variations in backscattering intensity (stable colloids without aggregation).