Objectives: The purpose of this research work was to formulate and systemically evaluate in vitro performances of polymeric microspheres of nifedipine. Methods: Nifedipine microspheres containing two polymers, poloxamer 407 and carbopol 934, were prepared by single emulsion cross-linking technique. Glutaraldehyde was selected as the cross-linking agent. A Box–Behnken design was employed to study the effect of independent variables, polymer concentration (X1), stirring speed (X2), and glutaraldehyde concentration (X3) on the dependent variables particle size, drug entrapment efficiency, and flow properties of microspheres. Results: Results of preliminary trials indicate that the polymer concentration, glutaraldehyde concentration, and stirring speed affected various characteristics of microspheres. The formulated Microspheres were discrete, spherical, and free flowing. The optimized batch exhibited with the narrow particle size of 75 μm, good flow properties, and drug entrapment efficiency of 96%. Conclusion: The polymeric microspheres of nifedipine with excellent flowability and good entrapment efficiency were successfully developed. These can be useful in improving patient compliance and bioavailability of nifedipine.

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A synthetic dipeptide, pidotimod (3-L-pyroglutamyl-L-thiaziolidine-4-carboxylic acid, PTD) is an immunomodulator and it possesses anti-infective activity against variety of infections. The objective of this study was to explore into and identify pidotimod’s major degradation product. Pidotimod was degraded in ICH prescribed stress conditions. pidotimod was degraded 90% in 1.0 N NaOH at 80 ºC for 6 h and the degradation product (DP2) was determined using HPLC. The HPLC method was used to separate the primary and subsidiary degradation products and carried out on a C18 column with a mobile phase of ammonium acetate buffer (pH 4.5; 10 mM) and MeOH/ACN (90:10 v/v) at a ratio of 97:03 v/v at 40 ºC, flow rate of 1.0 mL/min, and detection at 215 nm. IR, NMR and LC-MS-MS were used to identify degradation product (DP2) as 3,8-dihydroxy-tetrahydro-bisthiazolo[3,4,4a,3′,4′- d]pyrazine-5,10-dione.