Efficacy and Safety of a Lidocaine and Ropivacaine Mixture for Scalp Nerve Block and Local Infiltration Anesthesia in Patients Undergoing Awake Craniotomy.

BACKGROUND: Mixtures of various local anesthetics, such as lidocaine and ropivacaine, have been widely used. However, their efficacy and safety for scalp nerve blocks and local infiltration during awake craniotomy have not been fully elucidated. METHODS: We prospectively investigated 53 patients who underwent awake craniotomy. Scalp block was performed for the blockade of the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater occipital, and lesser occipital nerves with a mixture containing equal volumes of 2% lidocaine and 0.75% ropivacaine, including 5 µg/mL of epinephrine. Infiltration anesthesia was applied at the site of skin incision using the same mixture. The study outcomes included changes in heart rate and blood pressure after head pinning and skin incision, and incidence of severe pain on emergence from anesthesia. Total doses and plasma concentrations of lidocaine and ropivacaine were measured at different time points after performing the block. RESULTS: The heart rate and blood pressure after head pinning were marginally, but significantly, increased when compared with baseline values. There were no significant differences in heart rate and blood pressure before and after the skin incision. Nineteen percent of the patients (10/53) complained of incisional pain at emergence from anesthesia. The highest observed blood concentrations of lidocaine and ropivacaine were 1.9±0.9 and 1.1±0.4 µg/mL, respectively. No acute anesthetic toxicity symptom was observed. CONCLUSIONS: Scalp block with a mixture of lidocaine and ropivacaine seems to provide effective and safe anesthetic management in patients undergoing awake craniotomy.

The use of an in vitro dissolution and absorption system to evaluate oral absorption of two weak bases in pH-independent controlled-release formulations.

The aim of this study was to compare the oral absorption of two weak bases including their pH-independent controlled-release preparations using an in vitro evaluation system. This system is able to simulate dissolution of drugs, pH change and permeation of drugs through the epithelial cell membrane in the gastrointestinal tract. Albendazole-polymers solid dispersion and pH-independent sustained-release granules of dipyridamole were prepared by using a solvent method. Elution profiles and predicted absorption of these preparations in gastric pH conditions similar to those in healthy subjects and patients with achlorhydria were compared with those of a physical mixture and commercial tablets. When a physical mixture or commercial tablets were used, the elution profile and predicted absorption of both albendazole and dipyridamole were extremely pH-dependent. On the other hand, when a solid dispersion and granules were used, elution and predicted absorption were not affected by changes in pH of the flowing solution in a drug-dissolving vessel. These results are in agreement with the results of our previous in vivo study using gastric acidity-controlled rabbits. Our results suggest that this in vitro system is useful for the evaluation of oral absorption of pH-independent controlled-release preparations.

[Preparing oral dosage form of ketamine in the hospital for simplicity and patient compliance--preparations using agar].

Ketamine has been widely used in the operation as intravenous and intramuscular injections, since ketamine has dissociative anesthetic properties. When it is given in sub-anesthetic dose, ketamine is known to have an analgesic effect. The analgesic effect is observed for patients with neuropathic pain when administrated not only by injection but also orally. In Japan, since ketamine is not commercially available except injection forms, patients have to take it as solution of injections for the oral medication. Since the solution of injections has extremely bitter taste, patients intensely desire the development of preparations without the bitterness. In the present study, we prepared oral gel dosage forms of ketamine using agar. It is simple to prepare this dosage form, and most pharmacists can prepare it easily in many hospitals. This gel dosage form met content uniformity requirements and the shape of that was maintained intact during the dissolution test (for 10 hours). The release rate was reduced by additions of additives such as sugar and a flavor in the gel. The reason for the reduction in release could be the suppression of ketamine diffusion depended on the micro-viscosity of solution in the gel. The ketamine contents and the release profile of the gel preparations were unchanged at the room temperature for 12-week storage. The gel preparations in this study would be useful for the oral medication of ketamine, since it is easy for patients to carry them when they go out and the intensely bitter taste could be improved by the addition of a flavor.

[Preparation of water in oil type cream with high content of water containing Kochia scoparia fruit and Cnidium monnieri fruit].

Kikisui is a herbal lotion containing Kochia scoparia Fruit and Cnidium monnieri Fruit that is clinically used as an antipruritic for itchy dry skin. However, this formulation is unsuitable for inducing a prolonged effect. Here, we attempted to change the formulation from a lotion to a cream. The cream we chose was a water-in-oil (W/O) type emulsion for enhancing skin compatibility. In addition, the high water content imparts a sensation of coolness. However, it is difficult to prepare a stable W/O type cream with high water content using a mechanical mixing method. Instead, we prepared the W/O type emulsion using liquid crystals. Water containing cocamidopropyl betaine was added to a dispersed phase comprising an oil phase of oleic acid and liquid paraffin that was constantly stirred. Addition of an aqueous solution containing Kochia scoparia Fruit and Cnidium monnieri Fruit decreased the stability of the cream. However, addition of glycerin as a humectant, and ethyl p-hydroxybenzoate/n-butyl p-hydroxybenzoate as preservatives enhanced the stability of the cream. The stability of the emulsion was correlated with the apparent viscosity of the cream. The final W/O type cream had a water content of 83% and was stable for more than 6 months at 4°C. Furthermore, ostol, which is one of the main biologically active herbal compounds, was also stable for more than 6 months.