In Vitro Release Testing of Acyclovir Topical Formulations Using Immersion Cells

Formulation and optimisation of Ozenoxacin topical nano-emulgel including a comprehensive methodology to qualify and validate the critical parameters of an in-vitro release test method and ex-vivo permeation test

OBJECTIVE

The purpose of this study was to formulate, optimize Ozenoxacin topical nano-emulsion using factorial design followed by to prepare and evaluate nano-emulgel using validated in-vitro release testing (IVRT) technique for determination of Ozenoxacin release rate along with ex-vivo permeation testing (EVPT).Significance: Nano-emulgel is a proven delivery system for poorly soluble substances works by enhancing the solubility and bioavailability. Factorial design provides a systematic and efficient means to study the effect of multiple factors on responses. IVRT is an USP compendia technique utilized for performance analysis of semi-solid formulations.

METHODS

Nano-emulsion formulation optimization was done with factorial design, evaluated for globule size and % entrapment efficiency (EE). Nano-emulgels were characterized for assay, organic impurities, rheological behavior, IVRT, EVPT, and skin retention studies. IVRT validation was executed using vertical diffusion cells (VDCs).

RESULTS

Ozenoxacin nano-emulsion was optimized with 1:1 ratio of Oil: Smix, 3:1 ratio of Surfactant:Co-Surfactant, and 15000 RPM of homogenization speed which resulted 414.6 ± 5.2 nm globule size and 92.8 ± 2.1% entrapment efficiency. Results confirmed that IVRT and Reversed Phase - High Performance Liquid Chromatographic techniques were validated as per regulatory guidelines. In-vitro, ex-vivo drug release, and skin retention from the optimized nano-emulgel formulation was comparatively higher (∼1.5 times) than that from the innovator (OZANEXTM) formulation.

CONCLUSIONS

Based on these results, Ozenoxacin nano-emulgel can be considered an effective alternative and was found to be stable at 40 °C/75% RH and 30 °C/75% RH storage condition for 6 months.

QbD-assisted optimisation of liposomes in chitosan gel for dermal delivery of aceclofenac as synergistic approach to combat pain and inflammation

Aceclofenac (ACE) is a drug that was precisely devised to circumvent the shortcomings associated with diclofenac. However, ACE too corresponds to nonsteroidal anti-inflammatory drug (NSAID)-related adverse effects, but with a lower amplitude. The present investigation seeks to develop liposomes loaded with ACE adopting a central composite design (CCD) and formulate a chitosan-based hydrogel for synergistic anti-inflammatory efficacy and improved ACE dermal administration. On the basis of preliminary vesicle size, Poly Dispersity Index (PDI), and drug entrapment, the composition of lipid, cholesterol, and vitamin E TPGS were chosen as independent variables. The formulation composition met the specifications for an optimum liposomal formulation, with total lipid concentration (13.5% w/w), cholesterol concentration (10% w/w), and surfactant concentration (2% w/w). With particle size and PDI of 174.22 ± 5.46 nm and 0.285 ± 0.01 respectively, the optimised formulation achieved an entrapment effectiveness of 92.08 ± 3.56%. Based on the CCD design, the optimised formulation Acec-Lipo opt was chosen and was subsequently transformed to a chitosan-based gel formulation for in vitro drug release, penetration through the skin, in vivo analgesic therapeutic activity, and skin irritation testing. % age oedema inhibition was found to be greatest with the Acec-Lipo opt gel formulation, followed by Acec gel. These results reinforce the notion that the inclusion of chitosan resulted in a synergistic effect despite the same strength of the drug. The findings suggested that Acec-Lipo incorporated in chitosan gel for skin targeting might be an effective formulation for topical ACE administration in clinical subjects.

Impact of Apparatus and Adapter on In vitro Drug Release of Ophthalmic Semisolid Drug Products

PURPOSE

In vitro release testing (IVRT) is a widely used tool for evaluating the quality and performance of drug products. However, standardized sample adaptors or drug release apparatus setups for IVRT studies are still lacking for ophthalmic ointments. The aim of this study was to provide a better understanding of the impact of apparatus and sample adaptor setups on IVRT of ophthalmic ointments.

METHODS

Dexamethasone (DEX), a steroidal ingredient commonly used in ophthalmic drug products, was selected as a model drug. Ointments were prepared by mixing DEX in white petrolatum using a high shear mixer. A novel two-sided adapter was developed to increase the drug release surface area. DEX ointment was placed in one-sided or two-sided release adaptors coupled with 1.2 μm polyethersulfone membrane, and the drug release was studied in different USP apparatuses (I, II, and IV).

RESULTS

The sample adaptor setups had a minimal impact on cumulative drug release amount per area or release rate while USP IV apparatus with agitated flow enhanced drug release rates. The USP apparatus I with a two-sided semisolid adapter, which uses membranes on both sides, showed dramatically higher cumulative drug release and discriminative release profiles when evaluating ophthalmic formulations.

CONCLUSIONS

USP apparatuses and sample adaptors are critical considerations for IVRT. Two-sided semisolid adapter provides higher cumulative release, facilitating the discrimination between low drug content ophthalmic ointment formulations with good sensitivity and repeatability without affecting the drug release rate.

Development of an Optimal In vitro Release and Permeation Testing Method for Rectal Suppositories

Currently there are no compendial assays for testing drug release from rectal suppositories. It is therefore essential to study different in vitro release testing (IVRT) and in vitro permeation testing (IVPT) methods for identifying a suitable technique to compare in vitro drug release and to predict in vivo performance of rectal suppositories. In the present study, three different rectal suppository formulations of mesalamine (CANASA, Generic, and In-house) were studied for in vitro bioequivalence. All the different suppository products were characterized by performing weight variation, content uniformity, hardness, melting time, and pH tests. Viscoelastic behavior of the suppositories was also tested both in presence and absence of mucin. Four different IVRT techniques such as Dialysis, Horizontal Ussing Chamber, Vertical Franz cell, and USP apparatus 4. IVPT studies were performed using Horizontal Ussing chamber and Vertical Franz cell methods. Q1/Q2 equivalent products (CANASA, Generic) and a half-strength product were studied to understand the reproducibility, bio relevance, and discriminatory ability of the IVRT and IVPT methods. This study is the first of its kind where molecular docking studies were performed to determine the potential interactions of drug (mesalamine) with mucin, IVRT studies were conducted with and without the presence of mucin, and porcine rectal mucosa was used to perform IVPT tests. The USP 4 method and Horizontal Ussing chamber methods were found to be suitable IVRT and IVPT techniques, respectfully, for rectal suppositories. RLD (Reference Listed Drug) and Generic rectal suppositories were found to exhibit similar release rate and permeation profiles obtained from USP 4, and the IVPT studies, respectfully. Wilcoxon Rank Sum/Mann-Whitney rank test, conducted for the IVRT profiles obtained using USP 4 method, proved the sameness of RLD and Generic suppository products.

Novel modified vertical diffusion cell for testing of in vitro drug release (IVRT) of topical patches

The vertical diffusion cell is an in vitro laboratory device for the study of drug release and permeation of semi-solid topical formulations and topical patches. Both static and dynamic versions of the diffusion cell are used in practice, the operation of which can be automated. The device is available at a reasonable cost for smaller, mainly transdermal patches, the amount of sampling fluid is replenished at the same time as the sample, in the same amount as the amount sampled without automation of the system, and simultaneous replenishment of acceptor fluid by hydrostatic pressure helps keeping the acceptor chamber bubble-free.

Determination of Microstructural Impact on the Release of Drug from Hydroxypropyl Cellulose Gel by Validated In Vitro Release Test Method

Microstructure of a semisolid system is greatly influenced by the formulation composition and the processing parameters. Different polymers exhibit different three-dimensional structure and these have a great impact on the drug release properties. The current research focuses on studying the impact of hydroxypropyl cellulose gel microstructure on the release properties of chlorhexidine gluconate (CHX G). The two main investigating methods of microstructure were used namely, rheology and texture analysis to determine the differences in the formulations studied. The CHX G drug release study was performed using a developed and validated in vitro release test method, which is reproducible, discriminative, and robust to detect the formulation differences. The drug release results showed that there was appreciable difference in the release rates of the different formulations. The rheology and texture analysis data correlated well with the difference in the release rates. The formulations differences were further confirmed by a statistical approach using analysis of variance.