Effect of Lyophilization on Stability of PEG-Protein Conjugate: A Case Study with Peginterferon alfa-2b

Abstract The purpose of the present study was to develop stable lyophilized formulation of peginterferon alfa-2b which is acquiescent to the short lyophilization process. The present study evaluates the effect of buffering components and cryoprotectant(s) on depegylation of the peginterferon alfa-2b in combination with lyophilization process. Finally, a short lyophilization process was identified which can produce a stable pharmaceutical form of peginterferon alfa-2b without any depegylation during long-term storage. Formulations were analyzed mainly for depegylation by HP-size exclusion chromatography and in-vitro antiviral activity. Residual moisture content in the lyophilized product was also used as a key indicating parameter to check its role with respect to depegylation upon storage under various temperature conditions. It was observed that the peginterferon alfa-2b when formulated in presence of cryoprotectant like sucrose requires longer lyophilization process of about 5 days, irrespective of the buffering components used, to reduce the level of residual moisture content and thereby to produce the stable formulation without depegylation. A stable formulation in presence of high concentration of lactose as a cryoprotectant was developed which can withstand stresses exerted to protein-polymer conjugate during lyophilization phases without any significant depegylation. A short lyophilization process of about 48 hours can be utilized for peginterferon alfa-2b when formulated in presence of lactose as a cryoprotectant through which a stable lyophilized formulation can be produced as against longer process required when sucrose is used a cryoprotectant, which is essential from commercial point of view as lyophilization is a costly process.

Ocular surface findings in impression cytology after interferon a2b or mitomycin C in rabbits / Achados em citologia de impressão da superfície ocular após uso de interferon alfa-2b ou mitomicina C: estudo em coelho

ABSTRACT Objective: To describe ocular surface findings in impression cytology obtained from healthy rabbit conjunctiva treated with interferon alpha-2b eyedrop, and compare them to findings after use of mitomycin C 0.02%. Methods: An experimental study using a rabbit model was performed between September 2013 and October 2014 at the Faculdade de Medicina de Marília, Universidade Federal de São Paulo, Clínica de Olhos Moacir Cunha. Thirty New Zealand white rabbits were divided into 6 groups and received interferon alpha-2b or mitomycin C 0.02%. Impression cytology (IC) was performed prior to topical applications and at15, 30 and 60 days of use. The following variables were analyzed in impression cytology: goblet cells, cellularity, cell-to-cell adhesion, nucleus/cytoplasm ratio, nuclear chromatin, inflammatory cells keratinization, and cytomegaly. Results: The major findings in impression cytology after us of interferon alpha-2b included loss of goblet cells (50.8%), reduced cell-to-cell adhesion (26.2%), abnormal nucleus/cytoplasm ratio (20%) and reduced cellularity (15.4%). After use of mitomycin C 0.02%, the most common changes included loss of goblet cells (46.2%), abnormal nucleus/cytoplasm ratio (25.6%), less cell-to-cell adhesion (23.1%), and reduced cellularity (20.5%). There were no significant differences in any variable when comparing impression cytology after interferon alpha-2b and after mitomycin C 0.02%. Goblet cell loss was more pronounced at days 30 and 60, as compared to impression cytology at day 15 for both drugs. Conclusion: The loss of goblet cells, reduced cell-to-cell adhesion and cellularity, along with abnormal nucleus/cytoplasm ratio were the most common findings in impression cytology after use of interferon alpha-2b. These findings are similar to those described for use of mitomycin C 0.02%. ..

RESUMO Objetivo: Descrever os achados em citologia de impressão de conjuntiva sadia de coelho submetida ao uso de colírio de interferon alfa-2b e compará-los ao que foi encontrado após uso da mitomicina C 0,02%. Métodos: Estudo experimental realizado em modelo animal no período entre setembro de 2013 e outubro de 2014 nas dependências da Faculdade de Medicina de Marília, da Universidade Federal de São Paulo e da Clínica de Olhos Moacir Cunha. Trinta coelhos albinos da raça Nova Zelândia foram divididos em seis grupos e receberam interferon alfa-2b ou mitomicina C. A citologia de impressão foi realizada antes do início dos colírios e após 15, 30, 60 dias de seu uso. As seguintes variáveis foram analisadas na citologia de impressão: células caliciformes, celularidade, adesão intercelular, razão núcleo/citoplasma, cromatina, células inflamatórias, queratinização e citomegalia. Resultados: Os principais achados na citologia de impressão após o uso do interferon alfa-2b foram a redução de células caliciformes (50,8%), a diminuição da adesão intercelular (26,2%), a alteração da razão N/C (20%) e a redução da celularidade (15,4%). Após o uso da mitomicina C 0,02%, foram mais frequentes a redução das células caliciformes (46,2%), a alteração da razão N/C (25,6%), a adesão intercelular (23,1%) e a redução da celularidade (20,5%). Não houve diferença estatisticamente significante para nenhuma das variáveis estudas quando se compararam as citologias de impressão após interferon alfa-2b com as citologias de impressão após mitomicina C 0,02%. Independentemente da substância utilizada, as citologias colhidas 30 e 60 dias após início das drogas apresentaram maior redução de células caliciformes quando comparadas com as citologias de impressão colhidas após 15 dias. Conclusão: A redução das células caliciformes, a diminuição da adesão intercelular, a alteração da razão N/C e a diminuição da celularidade foram as alterações mais frequentes na citologia de impressão colhida após o uso de interferon alfa-2b. Os achados em citologias de impressão após o uso de interferon alfa-2b são semelhantes àqueles encontrados após o uso da mitomicina C 0,02%.