Preparation and evaluation of flutamide mucoadhesive microparticles loaded poloxamer suppositories

Formulation of oxybutynin chloride microparticle-loaded suppositories: in vitro characterization and in vivo pharmacokinetic study

Background

Oxybutynin chloride (OXC) is used to treat overactive urinary bladder. OXC is metabolized in the liver to N-desethyloxybutynin, which is mainly responsible for the anticholinergic side effects of OXC. Conventional oxybutynin suppositories formulated earlier have shown most common side effects, such as dry mouth, constipation and serious anticholinergic reaction. Hence the present research work deals with the formulation and characterization of OXC microparticle-loaded mucoadhesive suppositories which may remain adhered in the lower rectum and avoid first pass metabolism. The emulsification–ionic gelation method is employed to prepare OXC microparticles. Two formulation factors at three levels, i.e. polymer concentration and stirring speed, were selected. Sodium alginate (concentration 1–2%) and 1% w/v Carbopol 971P were used to prepare OXC microparticles. OXC microparticles were evaluated for various parameters such as production yield, entrapment efficiency, mucoadhesive strength, shape, size, zeta potential, Fourier Transform Infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, in vitro dissolution studies and stability studies. Suppositories loaded with OXC microparticles were prepared by the fusion method using Poloxamer 188 and propylene glycol and evaluated for various parameters like weight variation, disintegration time, in vitro dissolution study, stability study and pharmacokinetic study.

Results

Results of in vitro characterization revealed that optimized batch of OXC loaded microparticles exhibited production yield 94.024% entrapment efficiency 95.378% and mucoadhesion strength 95.544%, particle size range 764.04–894.13 µm, zeta potential − 14.5 mV, with 0.946 desirability. Consequences of DSC and XRPD evaluation shown that drug was effectively entrapped inside the microparticles. In vitro release studies revealed improvement in drug dissolution as a consequence of its entrapment into microparticles. SEM results showed that micelles were sphere-shaped. On rectal administration of OXC microparticles loaded suppository in male Sprague–Dawley Rats, the relative bioavailability was found 173.72%.

Conclusion

In vivo study elicits rapid increase in absorption of drug from microparticles loaded suppository when compared with the oral formulation and drug loaded suppository in rats. OXC microparticles loaded suppository is novel and promising drug delivery system for rectal administration and may avoid anticholinergic side effects of hepatic metabolite, N-desethyloxybutynin. These rectal drug delivery systems will be advantageous for efficient absorption of drugs and to avoid first pass metabolism.

Image Analysis: A Versatile Tool in the Manufacturing and Quality Control of Pharmaceutical Dosage Forms

In pharmaceutical sciences, visual inspection is one of the oldest methods used for description in pharmacopeias and is still an important part of the characterization and qualification of active ingredients, excipients, and dosage forms. With the development of technology, it is now also possible to take images of various pharmaceutical dosage forms with different imaging methods in a size range that is hardly visible or completely invisible to the human eye. By analyzing high-quality designs, physicochemical processes can be understood, and the results can be used even in the optimization of the composition of the dosage form and in the development of its production. The present study aims to show some of the countless ways image analysis can be used in the manufacturing and quality assessment of different dosage forms. This summary also includes measurements and an evaluation of, amongst others, a less studied dosage form, medicated foams.

A New Method To Identify Physically Stable Concentration of Amorphous Solid Dispersions (I): Case of Flutamide + Kollidon VA64

In this paper, a novel approach to determine stable concentration in API-polymer systems is presented. As a model, binary amorphous mixtures flutamide (FL) drug with a copolymer Kollidon VA64 (PVP/VA) have been used. It is worthwhile to note that finding an effective method to achieve this goal is a matter of great importance because physical stability of the amorphous pharmaceuticals is the key issue that is investigated worldwide. Due to the fact that molecular dynamics was found to be the crucial factor affecting physical stability of disordered pharmaceuticals, we examined it for both neat FL and its PVP/VA mixtures by means of broadband dielectric spectroscopy (BDS). Thorough investigation of the impact of polymeric additive on the molecular mobility of disordered FL reveals unusual, previously unreported behavior. Namely, simultaneously with the beginning of the recrystallization process, we observe some transformation from unstable supersaturated concentration of investigated mixture to the different, unknown concentration of FL-PVP/VA. Observed, during BDS experiment, transformation enables us to determine the limiting, highly physically stable concentration of FL in PVP/VA polymer (saturated solution), which is equivalent to FL + 41% wt. of PVP/VA. The described high physical stability of this unveiled system has been confirmed by means of long-term XRD measurements. According to our knowledge, this is the first time when such a behavior has been observed by means of BDS.