pOlmesartan medoxomil surface solid dispersion-based orodispersible tablets: formulation and in vitro characterization

Current Trends on Solid Dispersions: Past, Present, and Future

Solid dispersions have achieved significant interest as an effective means of enhancing the dissolution rate and thus the bioavailability of a range of weakly water-soluble drugs. Solid dispersions of weakly water-soluble drugs with water-soluble carriers have lowered the frequency of these problems and improved dissolution. Solid dispersion is a solubilization technology emphasizing mainly on, drug-polymer two-component systems in which drug dispersion and its stabilization is the key to formulation development. Therefore, this technology is recognized as an exceptionally useful means of improving the dissolution properties of poorly water-soluble drugs and in the latest years, a big deal of understanding has been accumulated about solid dispersion, however, their commercial application is limited. In this review article, emphasis is placed on solubility, BCS classification, and carriers. Moreover, this article presents the diverse preparation techniques for solid dispersion and gathers some of the recent technological transfers. The different types of solid dispersions based on the carrier used and molecular arrangement were underlined. Additionally, it summarizes the mechanisms, the methods of preparing solid dispersions, and the marketed drugs that are available using solid dispersion approaches.

Inhibition of Co-Crystallization of Olmesartan Medoxomil and Hydrochlorothiazide for Enhanced Dissolution Rate in Their Fixed Dose Combination

Olmesartan medoxomil (Olm) and hydrochlorothiazide (HCTZ) are fixed dose combination (FDC) for treatment of hypertension. They have hydrogen bonding sites and may interact during co-processing. The consequences of such interaction are not clear. This study investigated the possibility of this interaction during co-processing. The research was extended to inhibit deleterious interactions. The drugs were co-evaporated from ethanolic solution to maximize the chance of interaction. This was performed in the absence and presence of hydroxypropyl methylcellulose (HPMC) and/or aerosil. The products were characterized using Fourier transform infrared spectroscopy (FTIR), differential thermal analysis, and powder X-ray diffraction (PXRD) in addition to dissolution studies. Co-evaporation of Olm with HCTZ in the absence of excipients produced crystalline material with FTIR spectrum showing intermolecular hydrogen bonding. This material showed thermal pattern of new crystalline species. This was identified as Olm/HCTZ co-crystal by PXRD. This co-crystallization reduced the dissolution rate of both drugs. This co-crystallization was inhibited in the presence of HPMC, but the dissolution rate was not significantly enhanced accordingly. Co-processing in the presence of both HPMC and aerosil eliminated the co-crystallization and minimized the intermolecular drug-drug interaction with subsequent dissolution enhancement. The study introduced a composition for fixed dose combination of Olm and HCTZ with enhanced dissolution.

In vitro and in vivo effects of morin on the intestinal absorption and pharmacokinetics of olmesartan medoxomil solid dispersions

PURPOSE

In-situ evaluation to corroborate morin effects on the intestinal absorption and pharmacokinetic behavior of freeze-dried OLM-loaded solid dispersions with Caco-2 and in-vivo studies Methods: Intestinal transport and absorption studies were examined by Caco-2 permeability, in-situ single pass perfusion and closed-loop models along with in-vivo pharmacokinetic studies to evaluate and confirm the effect of P-gp-mediated activity of morin. We evaluated the intestinal membrane damage in the presence of morin by measuring the release of protein and lactate dehydrogenase (LDH) followed by using qualitative and quantitative morphometric analysis to describe the surface characteristics of intestinal epithelium.

RESULTS

Morin showed the highest P_eff value 13.8 ± 0.34 × 10^-6cm/s in jejunum than ileum (p < .01) at 100 µM with absorption enhancement of 1.31-fold together with enhanced (p < .01) secretory transport of 6.27 ± 0.27 × 10 ^-6cm/s in Caco-2 monolayer cells. Our findings noticed 2.37 (in-situ); 2.39 (in-vivo) and 1.43 (in-situ); 1.36 (in-vivo) fold increase in AUC_0-t with elevated C_max and shortened T_max for freeze-dried solid dispersion in the presence of morin as compared to pure OLM and freeze-dried solid dispersions without morin, respectively.

CONCLUSIONS

Our study demonstrated that increased solubilization through freeze-dried OLM-loaded solid dispersion together with efflux inhibition improved intestinal permeability to one system that might lead to novel solubilization and efflux pump inhibition as a novel alternative potential to increase oral absorption and bioavailability of OLM.