HPMC is the most widely used cellulose-based polymer, and its properties vary depending on the ratio of methoxy and hydroxypropyl substitution. Accordingly, the uses for each dosage form are also varied, and they are generally used as binders, coating agents, or film formers in the manufacture of tablets or granules of oral dosage forms. In particular, in recent years, it has been variously used in drug delivery systems that increase the efficiency of drugs in vivo.
In this study, by using HPMC as a pharmaceutical formulation, a hydrogel for transdermal drug delivery and a spray-dried solid dispersion for solubilization of poorly soluble drugs for oral use were obtained.
For a novel hydrogel formulation as a transdermal drug delivery system, a hydrogel composed of carrageenan derived from seaweed and locust bean gum which are mainly used in hydrogels as natural polymers, and a hydrogel including HPMC were prepared. SEM analysis was performed to confirm the morphological characteristics and the drug release characteristics were compared. The hydrogel containing 60-70% HPMC based on the solid content of 5% increased adhesive strength compared to the hydrogel not containing HPMC and exhibited improved viscoelasticity of the gel. In addition, it exhibited an ESR of about 20 g per unit g, indicating the potential as a carrier capable of controlling the release of a drug with a highly hygroscopic hydrogel. The cumulative release amount for 30 minutes of niacinamide of a hydrogel composition containing HPMC was 0.13 mg/cm³ for the hydrogels containing 70% HPMC (Hydrogel 4, Hydrogel 9) and 0.28 mg/cm³ for the hydrogels containing 60% (Hydrogel 7). As the content of HPMC in the composition in mg/cm³ decreased, the cumulative release amount increased. As for the HPMC of the hydrogel, the lower the content, the greater the release amount and the higher the content of Gum Extract (GH), and the difference according to the content of Algae Extract (AE) did not show a tendency.
The purpose of spray dried solid dispersion study was to investigate the selectivity of polymers and the suitability of spray drying to enhance nifedipine solubility. Nifedipine alone or in combination with polymers was dissolved in a mixed solvent of methylene chloride and ethanol. The hydrophilic polymers used were PVP K-30, HPMC, HPMCP, Eudragit, and HPMCAS. Each solid dispersion was prepared using a laboratory spray dryer. The spray-dried solid dispersants were characterized by SEM, DSC, and XRPD analysis, and dissolution tests compared the dissolution rates of nifedipine solid dispersants and nifedipine. The results showed that all spray-dried solid dispersions were in an amorphous form. Dissolution tests were performed at pH 1.2 (artificial gastric juice) and pH 6.8 (artificial intestinal juice) to evaluate solid dispersion solubility. The solid dispersion containing HPMC showed a notably enhanced dissolution rate under both pH conditions. Interestingly, HPMCP and HPMCAS showed almost no enhancement of dissolution behavior at pH 1.2, but a significant increase (10 times or higher) over that of the pure polymer at pH 6.8. Solubility enhancement of poorly soluble drugs differs markedly among the polymers used for spray drying. From the results, HPMCP and HPMCAS are suitable as carriers for drugs with poor solubility that require acid resistance.
A drug delivery system formulation for dermal and oral study using excipients with stable bioavailability, including HPMC, and a study on the solubilization and transdermal delivery efficiency of poorly soluble drugs were conducted. Additional application studies through follow-up development that can design and control the release characteristics of various biomedicals and cosmeceutical products by applying this formulation are needed.