Amorphous Solid Dispersion of Meloxicam Enhanced Oral Absorption in Rats With Impaired Gastric Motility.

Meloxicam (MEL) shows a slow onset of action in severe pain patients on account of delayed gastric motility. This study aimed to develop an amorphous solid dispersion (ASD) of MEL to achieve rapid oral absorption in severe pain patients. ASD formulations of MEL with hydroxypropylmethylcellulose (ASD-MEL/HPMC) and polyacrylates and polymethacrylates (ASD-MEL/EUD) were prepared and physicochemically characterized. Oral absorption behavior of MEL samples was also clarified in both normal and propantheline (PPT)-pretreated rats with impaired gastric motility. MEL in the formulations was amorphous, and ASD formulations of MEL exhibited high dissolution behavior in acidic solution. After oral administration of crystalline MEL (1 mg-MEL/kg), a 69% reduction in AUC0-4 was observed between normal and PPT-pretreated rats. For orally dosed ASD-MEL/HPMC (1 mg-MEL/kg), there were approximately 9- and 12-fold increases of AUC0-4 in normal and PPT-pretreated rats, respectively, in comparison with crystalline MEL (1 mg-MEL/kg). However, the oral absorption behavior of ASD-MEL/EUD (1 mg-MEL/kg) was low and similar to that of crystalline MEL. The infrared spectroscopic study revealed potent interactions between MEL and EUD, possibly leading to marked attenuation of MEL absorption. This ASD approach might provide rapid oral absorption of MEL in severe pain patients, possibly leading to better clinical outcomes.

Avoidance of food effect on oral absorption profile of itraconazole by self-micellizing solid dispersion approach.

The present study was aimed to avoid pharmacokinetic transitions of itraconazole (ITZ) evoked by high-fat meal intake by employing a self-micellizing solid dispersion (SMSD) approach. The dissolution behavior of SMSD/ITZ was assessed in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). To evaluate the food effect on the oral absorption profile of ITZ, a pharmacokinetic study was conducted on orally-dosed ITZ samples in fasted and high-fat meal-fed rats. Crystalline ITZ showed a 9.0-fold higher dissolution amount of ITZ in fed-state SGF (FeSSGF) than in fasted-state SGF (FaSSGF), whereas there was no significant difference in the dissolution amount of ITZ in SMSD/ITZ between FeSSGF and FaSSGF. In fed- and fasted-state SIF, SMSD/ITZ exhibited reduced variation of ITZ dissolution, possibly leading to suppression of the food effect on the dissolution behavior of ITZ. After the oral administration of crystalline ITZ to high-fat meal-fed rats, the oral bioavailability of ITZ was 14-fold higher than that in fasted rats. In contrast, orally-dosed SMSD/ITZ in fed rats exhibited limited transition of pharmacokinetic behavior regardless of food intake due to the improvement in the dissolution behavior of ITZ even under fasted conditions. SMSD technology could be an efficacious dosage option for the consistent oral absorption and clinical outcomes of ITZ.

Improved Dissolution of Dipyridamole with the Combination of pH-Modifier and Solid Dispersion Technology.

The aim of this study was to develop a pH-independent release formulation of dipyridamole (DP) by the combined use of pH-modifier technology and solid dispersion (SD) technology employing enteric polymer, Eudragit® S100 (Eud). Tartaric acid (TA) was selected as an appropriate pH-modifier in terms of improving the dissolution behavior of DP under neutral conditions. Upon optimization of the ratio of TA to DP, SD of DP with Eud and TA (SD-Eud/DP/TA) was prepared by a freeze-drying method. Scanning electron microscopic images revealed that DP was dispersed in the polymer in SD-Eud/DP/TA, and DP in SD-Eud/DP/TA was in an amorphous state, supported by powder X-ray diffraction and differential scanning calorimetry analyses. The dissolution behavior of SD-Eud/DP/TA was not dependent on the pH of the medium, although SD-Eud/DP exhibited very limited dissolution behavior under neutral conditions. Spectroscopic analysis suggested that there might be inter-molecular interaction among DP, TA and enteric polymer in SD-Eud/DP/TA, possibly leading to the stable pH-independent dissolution behavior of SD-Eud/DP/TA. TA in SD-Eud/DP/TA promoted the degradation of DP, suggesting that improving the stability of DP in SD-Eud/DP/TA might be key for its practical use. From these results, pH-independent dissolution behavior of SD-Eud/DP/TA could be achieved by an enteric polymer-based solid dispersion with a pH-modifier.

Improved oral absorption profile of itraconazole in hypochlorhydria by self-micellizing solid dispersion approach.

The present study was aimed to evaluate the applicability of a self-micellizing solid dispersion (SMSD) system of itraconazole (ITZ) with the use of Soluplus® to achieve improved dissolution and stable oral absorption of ITZ under hypochlorhydric conditions. The SMSD of ITZ (SMSD/ITZ) was prepared by the freeze-drying method. Physicochemical properties of SMSD/ITZ were assessed in terms of morphology, crystallinity, particle size, thermal behavior, dissolution profile, and stability. The pharmacokinetic profile of SMSD/ITZ was evaluated in both normal rats and omeprazole-treated rats as a hypochlorhydric model. From the crystallinity assessment, ITZ in SMSD/ITZ might exist in an amorphous state. The dissolution behavior of SMSD/ITZ was markedly improved under both acidic and neutral conditions through the formation of nano-micelles with a diameter of 127nm. The degradation of ITZ in SMSD/ITZ was negligible after storage under accelerated conditions at 40°C or 40°C/75%RH for 4weeks. Under light exposure, ca. 33% of ITZ in SMSD/ITZ was degraded, suggesting the need for protection from light. Although the oral absorption of crystalline ITZ was negligible, SMSD/ITZ showed an improved pharmacokinetic profile in normal rats, with an absolute bioavailability (BA) of 2.9%, and even 6.3% in the hypochlorhydric model. From these findings, SMSD technology could be beneficial for improving the absorption profiles of weak basic drugs, even in hypochlorhydric patients.

Self-micellizing solid dispersion of cyclosporine A with improved dissolution and oral bioavailability.

The present study aimed to develop a self-micellizing solid dispersion (SMSD) of cyclosporine A (CsA) using an amphiphilic block copolymer, poly[MPC-co-BMA], to improve the biopharmaceutical properties of CsA. The cytotoxicity of poly[MPC-co-BMA] was assessed in rat intestinal IEC-6 cells, and the pMB was less cytotoxic than polysorbate 80, a non-ionic surfactant with a wide safety margin. SMSD/CsA was prepared using a wet-milling system, and its physicochemical properties were characterized in terms of morphology, crystallinity, dissolution, particle size distribution, and stability. The SMSD/CsA exhibited immediate formation of fine micelles with a mean diameter of ca. 180 nm when introduced into aqueous media. There was marked improvement in the dissolution behavior of the SMSD/CsA compared with amorphous CsA. Even after storage at 40°C/75% relative humidity, the dissolution behavior of aged SMSD/CsA seemed to be almost identical to that of its freshly prepared equivalent, and CsA in aged SMSD/CsA was still in amorphous form. After oral administration of SMSD/CsA (10 mg CsA/kg) in rats, enhanced CsA exposure was observed with increases of Cmax and BA by ca. 11- and 42-fold, respectively, compared with those of amorphous CsA. The poly[MPC-co-BMA]-based SMSD formulation system might be an efficacious dosage option for CsA to achieve improvements in oral bioavailability.